Dissection of left orbit from a lateral approach
										 Relation of muscle fascia to Tenon's capsule; insertion of lateral rectus and inferior oblique muscles
										The bone of the orbital margin has been resected and the fascia which covered the insertion of the lateral rectus and inferior oblique muscles cut and reflected. The continuity of the muscle fascia with the bulbar fascia (Tenon's capsule) is visible. The lacrimal gland has been cut away except for  a few lobules of its inferior portion. THe lateral expansion of the aponeurosis of the levator palpebrae superioris muscle crosses this area(4). A few muscle fibres from this muscle appear to end in a the fascia related to the lacrimal gland (4, upper pointer).

														 1
						.
					 Falx cerebri  2
						.
					 Levator palpebrae superioris muscle  3
						.
					 Supraorbital nerve and artery  4
						.
					 Upper pointer: Inferior lacrimal gland Lower pointer: Lateral horn of aponeurosis of levator palpebrae superioris muscle  5
						.
					 Area of blending of fascia of lateral rectus muscle with that of the bulh  6
						.
					 Supraorbital margin  7
						.
					 Tunica conjunctiva bulbar  8
						.
					 Sclera  9
						.
					 Insertion of lateral rectus muscle  10
						.
					 Lateral rectus muscle  11
						.
					 Tunica conjunctiva bulbar (elevated together with anterior extension of bulbar fascia)  12
						.
					 Inferior oblique muscle and related fascia  13
						.
					 Artery and nerve to inferior oblique muscle  14
						.
					 Orbital branch of infraorbital artery  15
						.
					 Infraorbital nerve within infraorbital canal (cut open)  16
						.
					 Upper pointer: Superior anterior alveolar nerve Lower pointer: Mucoperiosteum of maxillary sinus  17
						.
					 Superior ophthalmic vein  18
						.
					 Upper pointer: Superior rectus muscle Lower pointer: Ophthalmic artery  19
						.
					 Frontal nerve  20
						.
					 Sheath of optic nerve (optic canal opened)  21
						.
					 Upper pointer: Branch of oculomotor nerve (III) to superior rectus muscle Lower pointer: Nasociliary nerve  22
						.
					 Common annular tendon (cut open to show contents of "oculomotor foramen")  23
						.
					 Abducens nerve (VI) entering lateral rectus muscle  24
						.
					 Ciliary ganglion  25
						.
					 Short ciliary nerves (no distinct long ciliary branches of nasociliary nerve were present)  26
						.
					 Posterior ciliary artery (long)  27
						.
					 Sheath of optic nerve  28
						.
					 Inferior rectus muscle  29
						.
					 Sphenoid sinus and sphenopalatine ganglion  30
						.
					 Artery of pterygoid canal  31
						.
					 Infraorbital artery (cut off)


Dissection of left orbit from a lateral approach
										 Lateral rectus muscle reflected; ciliary nerves and ganglion
										The lateral rectus muscle has been cut in its midportion and the ends reflected to display structures located more centrally in the orbit. These have been exposed by removal of lobules of fat and delicate connective tissue.

														 1
						.
					 Inferior lacrimal gland  2
						.
					 Supraorbital margin  3
						.
					 Orbital fat pad  4
						.
					 Lateral rectus muscle (cut end reflected anteriorly)  5
						.
					 Eyeball covered by bulbar fascia  6
						.
					 Sheath of optic nerve  7
						.
					 Short ciliary nerves  8
						.
					 Posterior ciliary artery (long)  9
						.
					 Inferior ophthalmic vein (note large communicating vein between this vessel and the superior ophthalmic vein)  10
						.
					 Periorbita  11
						.
					 Infraorbital artery and vein  12
						.
					 Superior wall orbit and levator palpebrae superioris muscle  13
						.
					 Superior rectus muscle  14
						.
					 Lacrimalis artery and vein and superior ophthalmic vein  15
						.
					 Upper pointer: Anterior limit of superior orbital fissure Lower pointer: Recurrent meningeal branch of lacrimal artery (cut off)  16
						.
					 Left pointer: Abducens nerve entering lateral rectus muscle Right pointer: Muscular branch of ophthalmic artery  17
						.
					 Lateral rectus muscle (cut and reflected posteriorly)  18
						.
					 Ciliary ganglion  19
						.
					 Upper pointer: Inferior rectus muscle Lower pointer: Branch of oculomotor nerve (III) to inferior oblique muscle  20
						.
					 Maxillary nerve (V)  21
						.
					 Sphenoid sinus  22
						.
					 Internal maxillary artery


Dissection of left orbit from a lateral approach
										 Relation of orbital structures to brain stem and cranial nerves II-V
										The brain has been removed except for the brain stem, optic chiasm and optic tracts. The tentorium has been cut away and the cavernous sinus opened to show the course of cranial nerves related to the orbit with the exception of the abducens nerve which remains almost completely covered.

														 1
						.
					 Olfactory tract right (cut off at attachment to olfactory trigone)  2
						.
					 Optic chiasm and internal carotid artery (cut off)  3
						.
					 Upper pointer: Optic nerve (II) Lower pointer: Anterior clinoid process (attachment of tentorium visible)  4
						.
					 Superior rectus muscle  5
						.
					 Lacrimal artery  6
						.
					 Lateral rectus muscle  7
						.
					 Ophthalmic nerve (V1)  8
						.
					 Maxillary nerve (V2)  9
						.
					 Sphenoid sinus  10
						.
					 Internal maxillary artery  11
						.
					 Pterygoid process sphenoid bone (partially resected)  12
						.
					 Internal pterygoid muscle  13
						.
					 Buccinator muscle  14
						.
					 Posterior clinoid process  15
						.
					 Base of peduncle (cut across)  16
						.
					 Upper pointer: Lateral geniculate body Lower pointer: Optic tract  17
						.
					 Oculomotor nerve (III)  18
						.
					 Trochlear nerve (IV)  19
						.
					 Tentorial nerve (recurrent meningeal branch of ophthalmic nerve, which in this specimen grossly appears to be a branch of the trochlear nerve; the tentorium has been cut away from the nerve)  20
						.
					 Trigeminal nerve (V)  21
						.
					 Semilunar ganglion (trigeminal)  22
						.
					 Major superficial petrous nerve  23
						.
					 Mandibular nerve (V3)  24
						.
					 External acoustic meatus


Dissection of left orbit from a lateral approach
										 Relation of orbital contents to structures within pterygopalatine fossa
										The lateral wall and part of the roof (16) of the orbit have been cut away and a narrow rim of bone left at the orbital margin (3) for orientation. The position of the superior and inferior orbital fissures may still be identified posteriorly near the roof and floor of the orbit because of the nerves (22,23,24), blood vessels (20,26), smooth muscle (11) and fascia which have been retained. For the size and shape of the fissures in the bony orbit reference should be made to 37-1.

														 1
						.
					 Remnant of superior lacrimal gland  2
						.
					 Lacrimal artery and vein  3
						.
					 Supraorbital margin  4
						.
					 Cut end of anastomotic branch of lacrimal nerve with zygomatic nerve  5
						.
					 Lateral check ligament  6
						.
					 Lateral rectus muscle  7
						.
					 Inferior musclar branch of ophthalmic artery  8
						.
					 Area of blending of fascias of lateral and inferior rectus muscles and inferior oblique muscle  9
						.
					 Zygomaticofacial branch of zygomatic nerve  10
						.
					 Periorbita of floor of orbit  11
						.
					 Orbital muscle (Müller's muscle situated within inferior orbital fissure)  12
						.
					 Infraorbital artery  13
						.
					 Mucoperiosteum of maxillary sinus  14
						.
					 Superior posterior alveolar nerve  15
						.
					 Levator palpebrae superioris muscle  16
						.
					 Superior wall orbit (cut away)  17
						.
					 Superior rectus muscle  18
						.
					 Lacrimal nerve  19
						.
					 Superior ophthalmic vein  20
						.
					 Recurrent branch of lacrimal artery which communicated through superior orbital fissure with middle meningeal artery)  21
						.
					 Anterior clinoid process  22
						.
					 Trochlear nerve (IV)  23
						.
					 Ophthalmic nerve (VI) entering Superior orbital fissure  24
						.
					 Abducens nerve (VI)  25
						.
					 Branch of oculomotor nerve (III) to inferior oblique muscle  26
						.
					 Upper pointer: Branch of Inferior ophthalmic vein Lower pointer: Orbital branch of sphenopalatine ganglion  27
						.
					 Foramen rotundum  28
						.
					 Upper pointer: Zygomatic nerve Lower pointer: Cut surface of greater wing of sphenoid bone  29
						.
					 Maxillary nerve (V2)  30
						.
					 Pharyngeal branch of artery of pterygoid canal  31
						.
					 Internal maxillary nerve plexus  32
						.
					 Internal maxillary artery


Dissection of left orbit from a lateral approach
										 Contents of orbit in relation to cranial cavity, brain stem and cavernous sinus
										The left half of the calvaria has been removed and the cerebral hemispheres cut away to expose the optic chiasm (4, lower pointer) and the left optic tract(19) which passes posteriorly to the lateral geniculate body (17). The cavernous sinus has been opened and the contents of the pterygopalatine fossa dissected. The lacrimal gland (7) has been partially resected and structures within the orbit more fully exposed than in previous views. Details of the dissection of the cavernous sinus are to be found in reels 50-7 and 51-1 ff.

														 1
						.
					 Falx cerebri  2
						.
					 Anterior cranial fossa right  3
						.
					 Lesser wing sphenoid bone (covered by dura mater)  4
						.
					 Upper pointer: Internal carotid artery right Lower pointer: Optic chiasm  5
						.
					 Olfactory tracts  6
						.
					 Superior rectus muscle  7
						.
					 Superior lacrimal gland (partially removed)  8
						.
					 Lacrimal artery  9
						.
					 Lateral rectus muscle  10
						.
					 Oculomotor nerve (III) (branch to inferior oblique muscle)  11
						.
					 Zygomatic nerve  12
						.
					 Internal maxillary artery  13
						.
					 Lateral plate of pterygoid process  14
						.
					 Middle cranial fossa right  15
						.
					 Upper pointer: Temporal bone (squamous part) (in background) Lower pointer: Pineal body  16
						.
					 Base of peduncle (cut across at transition into internal capsule)  17
						.
					 Lateral geniculate body left  18
						.
					 Edge of tentorium cerebelli (brain stem protrudes upward through tentorial incisure)  19
						.
					 Upper pointer: Optic tract Lowerpointer: Mesencephalon (pointer on base of peduncle)  20
						.
					 Upper pointer: Oculomotor nerve (III) within subarachnoid space Lower pointer: Oculomotor nerve (II) within cavernous sinus  21
						.
					 Trochlear nerve (IV) within cavernous sinus  22
						.
					 Ophthalmic nerve (V) within cavernous sinus  23
						.
					 Semilunar ganglion (trigeminal)  24
						.
					 Upper pointer: Maxillary nerve (V) within cavernous sinus Lower pointer: Mandibular nerve (V)  25
						.
					 Middle meningeal artery (cut across)  26
						.
					 Mastoid cells (dissected)


Dissection of left orbit from a lateral approach
										 Lateral rectus muscle; communication of lacrimal and zygomatic nerves
										The periorbita has been resected and the bony walls of the orbit cut away more than previously. A thin layer of fat separated the lateral rectus muscle from the periorbita. This fat has been removed from along with that surrounding other structures within the orbit. The fascia of the lateral rectus muscle is intact, but is extremely thin through most of its extent. Anteriorly the fascia thickens rapidly and has a broad attachment to the orbital tubercle of the zygomatic bone to form the lateral check ligament (6).

														 1
						.
					 Supraorbital nerve  2
						.
					 Superior lacrimal gland  3
						.
					 Anastomotic branch of lacrimal nerve with zygomatic nerve  4
						.
					 Periorbita (split into two layers to enclose lacrimal gland)  5
						.
					 Lateral palpebral raphe  6
						.
					 Lateral check ligament  7
						.
					 Tunica conjunctiva  8
						.
					 Fascia forming suspensory ligament for eye  9
						.
					 Inferior oblique muscle  10
						.
					 Dura mater of anterior cranial fossa  11
						.
					 Superior rectus muscle  12
						.
					 Lacrimal artery and nerve  13
						.
					 Middle meningeal artery (anterior branch)  14
						.
					 Superior ophthalmic vein (lacrimal veins visible as tributaries)  15
						.
					 Lateral rectus muscle  16
						.
					 Branch of oculomotor nerve (III) to inferior oblique muscle  17
						.
					 Inferior ophthalmic vein (situated in periorbita which bridges across inferior orbital fissure)  18
						.
					 Zygomatic nerve  19
						.
					 Infraorbital nerve  20
						.
					 Orbital muscle (of Müller)


Dissection of left orbit from a lateral approach
										 Periorbita
										The bony wall of the middle cranial fossa has been removed so that the dura mater (9), which encloses the tip of the temporal lobe, is exposed. The dura has been retracted to reveal the lateral wall of the orbit, from which the bone has been cut. Windows cut in the bone of the anterior cranial fossa expose the dura mater (8) in two locations.

														 1
						.
					 Superior lacrimal gland  2
						.
					 Superior tarsus  3
						.
					 Zygomaticofrontal suture  4
						.
					 Conjunctiva  5
						.
					 Inferior oblique muscle  6
						.
					 Zygomaticofacial branch of zygomatic nerve  7
						.
					 Temporal fossa  8
						.
					 Dura mater of anterior cranial fossa  9
						.
					 Dura mater indented into middle cranial fossa  10
						.
					 Middle meningeal artery  11
						.
					 Upper pointer: Periorbita Lower pointer: Cut surface of greater wing of sphenoid at anterior limit of middle cranial fossa  12
						.
					 Middle cranial fossa  13
						.
					 Zygomaticotemporal branch zygomatic nerve  14
						.
					 Maxillary nerve within pterygopalatine fossa  15
						.
					 Orbital muscle (Müller's muscle)  16
						.
					 Zygomatic branch of deep anterior temporal artery (cut oft)  17
						.
					 Infraorbital artery


Dissection of left orbit from a lateral approach
										 Relation of lacrimal gland to periorbita and zygomatic nerve
										The roof and lateral wall of the orbit have been cut away. The bony orbital margin has been preserved and the anterior wall of the middle cranial fossa (great wing of sphenoid bone) has been left undisturbed.

														 1
						.
					 Dura mater within anterior cranial fossa  2
						.
					 Supraorbital margin  3
						.
					 Periorbita (partially cut away to reveal lacrimal gland)  4
						.
					 Superior lacrimal gland  5
						.
					 Zygomaticofrontal suture  6
						.
					 Zygomaticotemporal branches zygomatic nerve  7
						.
					 Superior tarsus  8
						.
					 Lacrimal nerve (terminal branches)  9
						.
					 Lashes  10
						.
					 Upper pointer: Margin of skin Lower pointer: Inferior tarsus  11
						.
					 Conjunctiva  12
						.
					 Zygomaticofacial branches of zygomatic nerve  13
						.
					 Temporal fossa (origin of temporalis muscle)  14
						.
					 Anastomotic branch lacrimal nerve with zygomatic nerve  15
						.
					 Orbital fat pad


Arteries of right orbital region of newborn
										 Lateromedial roentgenogram
										After thorotrast had been injected into the right common carotid artery the head was section in the midsagittal plane and the brain removed. Near the apex of the orbit numerous muscular and ciliary arteries are visible but the identity of these is difficult to establish except for a few muscular branches which continue as anterior ciliary arteries (5,9). Many of the vessels have been omitted from the drawing.

														 1
						.
					 Superficial temporal artery (in foreground)  2
						.
					 Superior wall orbit  3
						.
					 Lacrimal artery (along lateral wall of orbit)  4
						.
					 Frontal artery (along roof of orbit)  5
						.
					 Upper pointer: Arterial branch to medial rectus muscle Lower pointer: Ophthalmic artery (also see 7)  6
						.
					 Middle meningeal artery (in foreground)  7
						.
					 Ophthalmic artery (within optic canal)  8
						.
					 Region of numerous small arterial branches including posterior ciliary arteries (short) and long and muscular branches (these branches are derived from all major branches of the ophthalmic artery but are not included in the drawing)  9
						.
					 Arteries to inferior rectus muscle and inferior oblique muscle  10
						.
					 Upper pointer: Deep anterior temporal artery Lower pointer: Deep posterior temporal artery  11
						.
					 Internal maxillary artery (pterygopalatine portion)  12
						.
					 Internal maxillary artery (pterygoid portion)  13
						.
					 Transverse facial artery (in foreground)  14
						.
					 Supraorbital artery  15
						.
					 Frontal artery  16
						.
					 Frontal bone (anterior margin)  17
						.
					 Anterior ethmoidal artery  18
						.
					 Middle palpebral artery  19
						.
					 Superior tarsal arch (peripheral arcade, in communication with branch of lacrimal artery laterally)  20
						.
					 Superior tarsal arch (marginal arcade, incompletely injected laterally)  21
						.
					 Dorsal nasal artery (in background)  22
						.
					 Communication between lacrimal artery and transverse facial artery (in foreground)  23
						.
					 Palpebral rim  24
						.
					 Inferior tarsal arch  25
						.
					 Left pointer: Infraorbital margin Right pointer: Anterior margin of fossa of lacrimal sac (in background)  26
						.
					 Upper pointer: Infraorbital artery Lower pointer: Superior posterior alveolar artery  27
						.
					 Buccal artery


Dissection of right orbit from a superior approach
										 Ciliary ganglion and connections; nerve supply to medial, inferior and lateral rectus muscles
										The ophthalmic artery and its branches have been cut away to reveal the ciliary nerves (4) and ganglion (8) as well as the nerves which enter the rectus muscles. A distinct bulge occurs in each of the extraocular muscles just anterior to the point of entry of motor nerves into the muscle substance. A filament from the ophthalmic sympathetic plexus (10) joins the ciliary ganglion.

														 1
						.
					 Ophthalmic artery  2
						.
					 Anterior ethmoidal artery  3
						.
					 Inferior wall of orbit  4
						.
					 Short ciliary nerves  5
						.
					 Medial rectus muscle  6
						.
					 Branches of oculomotor nerve (III) to medial rectus muscle  7
						.
					 Superior oblique muscle (cut off)  8
						.
					 Ciliary ganglion  9
						.
					 Nasociliary nerve (cut off)  10
						.
					 Filament from ophthalmic nerve plexus to ciliary ganglion  11
						.
					 Ophthalmic artery  12
						.
					 Trochlear nerve (IV) (cut off)  13
						.
					 Ophthalmic nerve (cut off)  14
						.
					 Anterior clinoid process  15
						.
					 Sheath of optic nerve  16
						.
					 Upper pointer: Position of macula lutea in interior of eyeball (marked by 4) Lower pointer: Insertion of inferior oblique muscle  17
						.
					 Lateral check ligament  18
						.
					 Branch of oculomotor nerve (III) to inferior oblique muscle  19
						.
					 Inferior rectus muscle  20
						.
					 Lateral rectus muscle  21
						.
					 Temporalis muscle  22
						.
					 Branch of oculomotor nerve (III) to inferior rectus muscle  23
						.
					 Abducens nerve (VI)  24
						.
					 Branch of oculomotor nerve (III) to superior rectus muscle (cut off)  25
						.
					 Middle cranial fossa


Dissection of right orbit from a superior approach
										 Branches of ophthalmic artery
										The optic nerve has been cut and the eye turned anteriorly. The central end of the optic nerve has been displaced from the optic canal to illustrate the course of the ophthalmic artery in a separate dural investment inferior to the nerve. Branches of this artery within the orbit presented such a complex pattern that it was necessary to displace the artery medially from its original position to demonstrate their arrangement. Branches to structures in the superior part of the orbit have been cut off. In the accompanying drawing smaller arterial branches have been omitted for the sake of simplicity.

														 1
						.
					 Frontal artery  2
						.
					 Medial check ligament  3
						.
					 Posterior ciliary artery (long) (within sclera)  4
						.
					 Anterior ethmoidal artery  5
						.
					 Medial rectus muscle  6
						.
					 Posterior ciliary artery  7
						.
					 Inferior muscular branch of ophthalmic artery (branches pass to medial, inferior and lateral rectus muscles and inferior oblique muscle)  8
						.
					 Posterior ethmoidal artery  9
						.
					 Lacrimal artery (cut off)  10
						.
					 Ciliary ganglion  11
						.
					 Optic nerve (II) (elevated  12
						.
					 Ophthalmic artery entering optic canal  13
						.
					 Internal carotid artery  14
						.
					 Insertion of superior oblique muscle  15
						.
					 Lacrimal gland (inferior)  16
						.
					 Lateral check ligament  17
						.
					 Posterior ciliary arteries (short)  18
						.
					 Optic nerve (ll) within sheath  19
						.
					 Lateral rectus muscle  20
						.
					 Central artery of retina (continuity of artery interrupted in drawing but not in specimen)  21
						.
					 Posterior ciliary artery  22
						.
					 Origin of superior rectus muscle (cut off)  23
						.
					 Nerves entering orbit through superior orbital fissure


Dissection of right orbit from a superior approach
										 Ophthalmic artery; ciliary nerves and arteries; sheath of optic nerve; insertion of superior oblique muscle
										The superior rectus muscle has been cut and reflected to expose underlying structures. The fascia of the bulb (Tenon's capsule) has been partially cut away. Short ends of two vorticose veins (16) protrude from the sclera. In this specimen the ophthalmic artery passes beneath the optic nerve rather than above it. This is a rather common variation.

														 1
						.
					 Superior oblique muscle  2
						.
					 Bulbar fascia  3
						.
					 Sclera  4
						.
					 Anterior ethmoidal artery  5
						.
					 Upper pointer: Infratrochlear nerve Lower pointer: Anterior ethmoidal nerve  6
						.
					 Superior oblique muscle  7
						.
					 Medial rectus muscle  8
						.
					 Ophthalmic artery  9
						.
					 Sheath of optic nerve  10
						.
					 Branch of oculomotor nerve entering superior rectus muscle  11
						.
					 Superior rectus muscle (cut and reflected)  12
						.
					 Optic nerve (II)  13
						.
					 Aponeurosis of levator palpebrae superioris muscle  14
						.
					 Superior rectus muscle (pointer near junction of muscle with tendon of insertion)  15
						.
					 Insertion of superior oblique muscle  16
						.
					 Vorticose veins (cut off)  17
						.
					 Lateral check ligament  18
						.
					 Short ciliary nerves  19
						.
					 Lateral rectus muscle  20
						.
					 Lacrimal artery  21
						.
					 Posterior ciliary artery  22
						.
					 Abducens nerve (VI)


Dissection of right orbit from a superior approach
										 Superior rectus muscle and related fascia
										The levator palpebrae superioris muscle has been cut and reflected anteriorly. The fascia (18) of the inferior surface of this muscle blends with that of the superior rectus muscle in the region of the eye. In addition, the fascia of the superior rectus muscle spreads medially (5) and laterally (20) to fuse with the fascia from neighboring rectus muscles. The tendon of the superior oblique muscle has been lifted from its trochlea (3). Note that the reflected part of this tendon, which passes under the superior rectus muscle, is encased in dense fascia continuous with that already described.

														 1
						.
					 Corrugator supercilii muscle and frontal artery  2
						.
					 Supratrochlear nerve (cut off)  3
						.
					 Superior oblique muscle  4
						.
					 Tendon of superior oblique muscle  5
						.
					 Medial expansion of fascia of superior rectus muscle  6
						.
					 Bulbar fascia  7
						.
					 Cribriform plate ethmoid bone  8
						.
					 Medial rectus muscle  9
						.
					 Superior oblique muscle and trochlear nerve (IV)  10
						.
					 Nasociliary nerve  11
						.
					 Artery ethmoidalis posterior  12
						.
					 Ophthalmic artery  13
						.
					 Common annular tendon  14
						.
					 Optic nerve (II) and anterior clinoid process  15
						.
					 Optic chiasm  16
						.
					 Internal carotid artery and optic tract  17
						.
					 Levator palpebrae superioris muscle (reflected)  18
						.
					 Fascia beneath levator muscle (17)  19
						.
					 Lacrimal gland (inferior)  20
						.
					 Lateral expansion of fascia of superior rectus muscle  21
						.
					 Lateral check ligament  22
						.
					 Superior rectus muscle  23
						.
					 Lateral rectus muscle


Dissection of right orbit from a superior approach
										 Insertion of levator palpebrae superioris muscle, anterosuperior view
										The aponeurosis of insertion of the levator palpebrae superioris muscle (6) has been exposed. The superior part of the lacrimal gland has been cut away and the fascia removed from the aponeurosis. The upper eyelid (13) has been dissected to display the extension of this aponeurosis onto the anterior surface of the tarsus (12) as well as its attachment to the skin anterior to the tarsus (14). This insertion is also visible in reel 52-3. The insertion of the lateral "horn" of the aponeurosis into the orbital tubercle of the zygoma is visible at 11. The medial "horn" of the aponeurosis (23) extends downward toward the medial wall of the orbit. Variation in thickness of the bone of the lateral wall of the orbit is well shown in this view.

														 1
						.
					 Middle cranial fossa  2
						.
					 Sheath of optic nerve  3
						.
					 Lateral rectus muscle  4
						.
					 Superior rectus muscle  5
						.
					 Temporalis muscle (within temporal fossa)  6
						.
					 Levator palpebrae superioris muscle and its aponeurosis  7
						.
					 Lacrimal nerve  8
						.
					 Lateral check ligament  9
						.
					 Area for lacrimal gland  10
						.
					 Frontosphenoidal process of zygomatic bone  11
						.
					 Lateral horn of aponeurosis of levator palpebrae superioris muscle  12
						.
					 Aponeurosis of levator palpebrae superioris muscle extending to anterior surface of superior tarsus  13
						.
					 Superior palpebra  14
						.
					 Cutaneous insertion of fibers of aponeurosis of levator palpebrae superioris muscle (partially cut across)  15
						.
					 Ethmoidal cell (medial)  16
						.
					 Superior oblique muscle  17
						.
					 Medial rectus muscle  18
						.
					 Ophthalmic artery  19
						.
					 Ethmoidal cell (anterior)  20
						.
					 Frontal sinus  21
						.
					 Superior oblique muscle  22
						.
					 Fascia surrounding reflected part of tendon of superior oblique muscle  23
						.
					 Medial horn of aponeurosis of Ievator palpebrae superioris muscle  24
						.
					 Frontal artery  25
						.
					 Corrugator supercilii muscle


Dissection of right orbit from a superior approach
										 Relation of aponeurosis of levator palpebrae superioris muscle to tendon of superior oblique muscle and lacrimal gland
										The bone of the orbital margin has been resected and the fascia covering the levator palpebrae muscle removed. Subcutaneous structures of the supraorbital region (13-16) have been preserved along with the thickened rim of periorbita at the margin of the orbit (17). The superior orbital fissure (24) has been opened to display nerves which traverse it. The superior ophthalmic vein has been removed.

														 1
						.
					 Frontal sinus  2
						.
					 Superior oblique muscle  3
						.
					 Reflected part of tendon of superior oblique muscle (the thick fascia which surrounds the tendon blends with fascia of the levator and superior rectus muscles as well as with the bulbar fascia)  4
						.
					 Supratrochlear nerve  5
						.
					 Ophthalmic artery  6
						.
					 Fascia covering medial rectus muscle  7
						.
					 Anterior ethmoidal artery and nerve (entering anterior ethmoidal foramen)  8
						.
					 Superior oblique muscle  9
						.
					 Levator palpebrae superioris muscle  10
						.
					 Posterior ethmoidal artery (posterior ethmoidal nerve absent)  11
						.
					 Upper pointer: Common annular tendon Lower pointer: Trochlear nerve (IV)  12
						.
					 Optic nerve (II)  13
						.
					 Corrugator supercilii muscle  14
						.
					 Supraorbital artery (supraorbital branch of ophthalmic artery absent in this specimen)  15
						.
					 Supraorbital nerve  16
						.
					 Communicating branch between supraorbital nerve and facial nerve  17
						.
					 Periorbita at supraorbital margin  18
						.
					 Aponeurosis of levator palpebrae superioris muscle  19
						.
					 Superior lacrimal gland  20
						.
					 Superior rectus muscle  21
						.
					 Eyeball  22
						.
					 Lateral rectus muscle  23
						.
					 Lacrimal nerve  24
						.
					 Superior orbital fissure (opened)


Dissection of right orbit from a superior approach
										 General relations of structures within orbit; orbital fascia
										Bone has been cut away from the roof of the orbit and the ethmoidal sinuses opened. The periorbita has been resected and the orbital fat removed. The arrangement of muscle fascia anteriorly in the orbit is of particular interest. The muscles have not yet been stripped of intrinsic fascia, but this is so thin posteriorly that it is barely discernable except over the superior oblique muscle (12). The fascia becomes dense only where the muscles approach the eye. Here it spreads away from the muscle borders into neighboring areas.

														 1
						.
					 Frontal sinus (opened)  2
						.
					 Position of superior oblique muscle  3
						.
					 Branch of frontal nerve which communicates with infratrochlear nerve  4
						.
					 Fascia of superior oblique muscle  5
						.
					 Ophthalmic artery  6
						.
					 Olfactory nerve (I)  7
						.
					 Infratrochlear nerve  8
						.
					 Superior ophthalmic vein  9
						.
					 Olfactory bulb  10
						.
					 Anterior ethmoidal nerve  11
						.
					 Ethmoidal air cell (medial)  12
						.
					 Superior oblique muscle  13
						.
					 Upper pointer: Posterior ethmoidal artery Lower pointer: Ethmoidal cell (posterior)  14
						.
					 Trochlear nerve (IV)  15
						.
					 Roof of optic canal (upper root of lesser wing of sphenoid bone  16
						.
					 Dura mater and optic nerve (II)  17
						.
					 Anterior clinoid process  18
						.
					 Supratrochlear nerve  19
						.
					 Frontal nerve (supraorbital and frontal branches not separated)  20
						.
					 Fascia of levator palpebrae superioris muscle  21
						.
					 Levator palpebrae superioris muscle  22
						.
					 Fascia of superior rectus muscle  23
						.
					 Periorbita  24
						.
					 Superior rectus muscle  25
						.
					 Lacrimal nerve, artery, and vein  26
						.
					 Temporalis muscle  27
						.
					 Superior ophthalmic vein  28
						.
					 Frontal nerve


Palpebral arteries
										 Anterior view of right eyelids
										The margins of the lids, the tarsal plates and the conjunctival sac have been exposed. The orbital roof and levator palpebrae superioris muscle have been cut away and the orbital fat removed.

														 1
						.
					 Superior oblique muscle (tendon removed)  2
						.
					 Right pointer: Ophthalmic artery (in depths of dissection) Left pointer: Sclera  3
						.
					 Conjunctiva (outer surface)  4
						.
					 Upper pointer: Superior tarsal arch (peripheral arcade) Lower pointer: Superior tarsus  5
						.
					 Superior tarsal arch (marginal arcade)  6
						.
					 Skin of lid margin  7
						.
					 Lateral palpebral branch of lacrimal artery  8
						.
					 Superior tarsal branch of zygomatico-orbital artery (this vessel has only minute branches communicating with lacrimal artery (7)  9
						.
					 Orbital margin (cut across)  10
						.
					 Lateral palpebral raphe  11
						.
					 Lateral palpebral branch of zygomatico-orbital artery  12
						.
					 Inferior tarsal branch of zygomatico-orbital artery  13
						.
					 Inferior tarsus  14
						.
					 Upper pointer: Palpebral cunjunctiva (outer surface) Lower pointer: Sclera  15
						.
					 Orbicularis oculi muscle  16
						.
					 Orbital branch of transverse facial artery  17
						.
					 Infraorbital margin  18
						.
					 Orbital branch of infraorbital artery  19
						.
					 Frontal artery  20
						.
					 Supraorbital vein  21
						.
					 Small artery which enters osseous canal in frontal process of maxilla  22
						.
					 Dorsal nasal artery  23
						.
					 Upper pointer: Middle palpebral artery (superior) Lower pointer: Medial check ligament  24
						.
					 Middle palpebral artery (inferior)  25
						.
					 Arterial branch to lacrimal caruncle  26
						.
					 Medial palpebral ligament  27
						.
					 Area of origin of orbicularis oculi muscle  28
						.
					 Arterial branch to lacrimal sac  29
						.
					 Inferior tarsal arch (marginal and peripheral arcades are present but not as well defined as in upper eyelid)  30
						.
					 Left pointer: Anterior ciliary artery Right pointer: Inferior rectus muscle  31
						.
					 Inferior oblique muscle  32
						.
					 Angular vein  33
						.
					 Angular artery


Dissection of left orbit from an anterior approach
										 Lacrimal sac and nasolacrimal duct opened
										Valve-like mucosal folds (15) are visible in the nasolacrimal duct. The one which guards the opening of the duct into the inferior nasal meatus (valve of Hasner, 17) extends about 5 mm. below the opening of the bony nasolacrimal canal (16). The tendon of the superior oblique muscle has been exposed within the trochlea (4) and its relation to the insertion of the levator palpebrae superioris muscle displayed.

														 1
						.
					 Dura mater  2
						.
					 Supraorbital nerve and vein  3
						.
					 Supratrochlear nerve  4
						.
					 Tendon of superior oblique muscle  5
						.
					 Infratrochlear nerve and dorsal nasal artery  6
						.
					 Nasal bone  7
						.
					 Middle palpebral artery (inferior)  8
						.
					 Fornix lacrimal sac  9
						.
					 Frontal process of maxilla  10
						.
					 Site of entry of lacrimal canaliculi into lacrimal sac (sinus of Maier)  11
						.
					 Lacrimal sac (opened)  12
						.
					 Infraorbital margin  13
						.
					 Nasolacrimal duct (opened; upper pointer, cavity; lower pointer, outer surface)  14
						.
					 Middle nasal concha and middle nasal meatus  15
						.
					 Mucosal folds within nasolacrimal duct  16
						.
					 Inferior nasal concha (cut across to illustrate bony wall of nasolacrimal canal)  17
						.
					 Left pointer: Lacrimal folds Right pointer: Opening of nasolacrimal duct  18
						.
					 Mucosa of Inferior nasal concha (note venous plexus)  19
						.
					 Inferior nasal meatus  20
						.
					 Nasal septum  21
						.
					 Superior tarsalis muscle  22
						.
					 Superior tarsus  23
						.
					 Lacrimal puncta and ampulla of superior lacrimal duct  24
						.
					 Inferior Iacrimal punctum  25
						.
					 Medial ocular angle  26
						.
					 Inferior lacrimal duct  27
						.
					 Inferior conjunctival fornix  28
						.
					 Inferior oblique muscle  29
						.
					 Periosteal lining of nasolacrirnal canal  30
						.
					 Infraorbital foramen  31
						.
					 Superior anterior alveolar artery


Dissection of left orbit from an anterior approach
										 Lacrimal sac; bony nasolacrimal canal opened
										The lacrimal sac (6) has been uncovered by removal of the medial palpebral ligament and reflection of the lacrimal fascia (5). The lacrimal canaliculi converge toward a common opening through the lateral wall of the sac. The bony nasolacrimal canal and nasal fossa have been exposed by grinding away part of the maxilla and nasal bone. The periosteal lining of the nasolacrimal canal is undisturbed. A thin edge of the infraorbital margin remains at 13.

														 1
						.
					 Infratrochlear nerve  2
						.
					 Fibers of origin of orbicularis oculi muscle  3
						.
					 Nasal bone  4
						.
					 Frontal process of maxilla  5
						.
					 Lacrimal fascia (cut away)  6
						.
					 Lacrimal sac  7
						.
					 External nasal branches anterior ethmoidal nerve  8
						.
					 Lateral nasal cartilage  9
						.
					 Cut edge of maxilla  10
						.
					 Periosteum lining nasal fossa  11
						.
					 Medial bony wall of nasolacrimal canal  12
						.
					 Periosteal lining of nasolacrimal canal  13
						.
					 Infraorbital margin  14
						.
					 Nasal cavity  15
						.
					 Mucosal lining of nasal septum (dissected)  16
						.
					 Septal cartilage  17
						.
					 Mucosal lining of lateral wall of nose (dissected)  18
						.
					 Inferior nasal concha (line of attachment to wall of nasal fossa)  19
						.
					 Middle palpebral artery  20
						.
					 Superior lacrimal duct (opened)  21
						.
					 Lacrimal puncta  22
						.
					 Upper pointer: Lacrimal caruncle Lower pointer: Inferior lacrimal duct (opened)  23
						.
					 Inferior conjunctival fornix  24
						.
					 Inferior oblique muscle  25
						.
					 Fascia of inferior oblique muscle  26
						.
					 Orbital fat pad  27
						.
					 Anterior superior alveolar artery  28
						.
					 Infraorbital artery and nerve


Dissection of left orbit from an anterior approach
										 Bulbar conjunctiva; lacrimal canaliculi opened
										The palpebral conjunctiva has been removed from both eyelids to expose the conjunctival fornices and bulbar conjunctiva. The tarsal plates, medial and lateral palpebral ligaments and lacrimal canaliculi remain in place. The canaliculi have been opened (5,9) to reveal their ampullae.

														 1
						.
					 Supratrochlear nerve  2
						.
					 Superior oblique muscle  3
						.
					 Middle palpebral artery  4
						.
					 Lacrimal fascia overlying lacrimal sac (some fibers of origin of the orbicularis oculi muscle remain)  5
						.
					 Ampulla of superior lacrimal duct (opened)  6
						.
					 Superior lacrimal duct  7
						.
					 Medial palpebral ligament  8
						.
					 Medial ocular angle  9
						.
					 Ampulla inferior lacrimal duct (opened)  10
						.
					 Infraorbital margin  11
						.
					 Inferior oblique muscle  12
						.
					 Fascia of levator palpebrae superioris muscle  13
						.
					 Aponeurosis of levator palpebrae superioris muscle (cut off)  14
						.
					 Superior tarsalis muscle (cut across)  15
						.
					 Superior conjunctival fornix  16
						.
					 Bulbar conjunctiva  17
						.
					 Superior tarsus  18
						.
					 Lacrimal nerve  19
						.
					 Skin supporting cilia of lower lid  20
						.
					 Inferior tarsus  21
						.
					 Bulbar conjunctiva  22
						.
					 Fascia forming suspensory ligament of eye


Dissection of left orbit from an anterior approach
										 Tarsal plates; lacrimal canaliculi; fascia supporting eye
										The supporting tarsal muscle (16) has been detached from the margin of the tarsus and resected to uncover the conjunctival membrane (17). The orbital septum has been cut away to expose the trochlea encased in dense fascia. The fascia (24) which encloses the inferior oblique muscle (12) extends laterally to the orbital tubercle of the zygoma and medially to the posterior lacrimal crest. It also blends with the fascia of the inferior rectus muscle and with the fascia of the bulb. The sling-like support thus formed for the eye is often referred to as the suspensory ligament (of Lockwood).

														 1
						.
					 Supraorbital nerve  2
						.
					 Supratrochlear nerve and superior oblique muscle  3
						.
					 Infratrochlear nerve  4
						.
					 Nasofrontal vein  5
						.
					 Middle palpebral artery  6
						.
					 Orbital fascia converging toward attachment to posterior lacrimal crest  7
						.
					 Origin of superior part of orbicularis oculi muscle  8
						.
					 Superior lacrimal duct  9
						.
					 Medial palpebral ligament  10
						.
					 Medial ocular angle  11
						.
					 Inferior lacrimal duct  12
						.
					 Inferior oblique muscle  13
						.
					 Supraorbital margin  14
						.
					 Fascia of levator palpebrae superioris muscle  15
						.
					 Aponeurosis of levator palpebrae superioris muscle  16
						.
					 Superior tarsalis muscle (cut across)  17
						.
					 Conjunctiva  18
						.
					 Superior tarsus and tarsal (Meibomian) glands  19
						.
					 Zygomaticofrontal suture  20
						.
					 Lateral palpebral artery  21
						.
					 Lacrimal nerve  22
						.
					 Inferior tarsus  23
						.
					 Conjunctiva  24
						.
					 Upper pointer: Suspensory ligament of eye (see text above) Lower pointer: fat pad of orbit


Dissection of left orbit from an anterior approach
										 Inferior lacrimal part of orbicularis oculi muscle
										The muscle fibers have been separated to show their inward extension toward the lacrimal fascia. This portion of the orbicularis muscle together with its counterpart in the upper eyelid is known as Horner's muscle. The underlying orbital septum (18) is not as distinctly membranous here as it is in the upper part of the orbit.

														 1
						.
					 Infratrochlear nerve  2
						.
					 Middle palpebral artery  3
						.
					 Orbital septum  4
						.
					 Origin of superior part of orbicularis oculi muscle  5
						.
					 Medial palpebral ligament  6
						.
					 Nasomaxillary suture  7
						.
					 Origin of inferior part of orbicularis oculi muscle  8
						.
					 Artery in periosteum  9
						.
					 Lateral nasal cartilage  10
						.
					 Deep vein (unnamed)  11
						.
					 Medial horn of aponeurosis of levator palpebrae superioris muscle  12
						.
					 Medial part of superior tarsalis muscle (Müller's muscle, composed here of connective tissue with no evident smooth muscle fibers)  13
						.
					 Superior tarsus  14
						.
					 Upper pointer: Superior lacrimal duct Lower pointer: Position of lacrimal puncta  15
						.
					 Medial ocular angle (medial canthus)  16
						.
					 Lacrimal part orbicularis. oculi muscle  17
						.
					 Middle palpebral artery  18
						.
					 Orbital septum  19
						.
					 Infraorbital margin


Dissection of left orbit from an anterior approach
										 Relation of orbital septum to aponeurotic and smooth muscle insertions of levator palpebrae superioris muscle
										The aponeurosis of the levator palpebrae superioris muscle has been cut back so that the entire extent of the tarsal muscle is visible. Smooth muscle fibers are less evident in the extreme lateral and medial parts of this layer. The orbital septum does not appear to be a complete membrane in the lateral and inferior parts of the orbit, but rather consists of fibrous bands intermingled with lobules of fat. The layer of connective tissue which extended betweeen the orbicularis oculi muscle and the orbital septum has been completely removed.

														 1
						.
					 Supraorbital nerve, artery, and vein  2
						.
					 Remnant of origin of corrugator supercilli muscle  3
						.
					 Orbital septum (detached from aponeurosis of levator palpebrae muscle)  4
						.
					 Supratrochlear nerve  5
						.
					 Upper pointer: Position of trochlea Lower pointer: Infratrochlear nerve  6
						.
					 Nasofrontal vein emerging from orbit  7
						.
					 Area of origin of upper part of orbicularis oculi muscle  8
						.
					 Middle palpebral artery  9
						.
					 Superior canaliculus  10
						.
					 Medial palpebral ligament  11
						.
					 Nasal bone  12
						.
					 Fibers of orbicularis oculi muscle (cut across near origin)  13
						.
					 Nasomaxillary suture  14
						.
					 Frontal process of maxilla  15
						.
					 Small artery along periosteum  16
						.
					 Zygomaticomaxillary suture  17
						.
					 Supraorbital margin of orbit  18
						.
					 Fascia of levator palpebrae superioris muscle  19
						.
					 Aponeurosis of Ievator palpebrae superioris muscle  20
						.
					 Zygomatic process frontal bone  21
						.
					 Superior tarsalis muscle (muscle of Müller)  22
						.
					 Superior tarsus and tarsal (Meibomian) glands  23
						.
					 Lateral palpebral artery  24
						.
					 Inferior tarsus  25
						.
					 Orbital branch (aberrant) from external maxillary artery  26
						.
					 Orbital septum  27
						.
					 Zygomatico-facial branch of zygomatic nerve  28
						.
					 Zygomatic bone


Dissection of left orbit from an anterior approach
										 Muscle fibers near medial angle of eyelids
										Note that no fibers attach to the anterior surface of the medial palpebral ligament.

														 1
						.
					 Infratrochlear nerve  2
						.
					 Muscle fibers which joined frontalis muscle  3
						.
					 Periosteum covering nasal bone  4
						.
					 Area of origin of superior part of orbicularis oculi muscle  5
						.
					 Area of origin of inferior part of orbicularis oculi muscle  6
						.
					 Lacrimal part orbicularis oculi muscle  7
						.
					 Medial palpebral ligament  8
						.
					 Angular head of levator labii superioris muscle (cut across)  9
						.
					 Frontal nerve  10
						.
					 Corrugator supercilii muscle  11
						.
					 Supratrochlear nerve  12
						.
					 Orbital septum (note its downward extension deep to the orbicularis muscle toward an attachment on the posterior lacrimal crest)  13
						.
					 Aponeurosis of levator palpebrae superioris muscle (upper pointer, cutaneous insertion; lower pointer, tarsal insertion)  14
						.
					 Superior tarsus  15
						.
					 Middle palpebral artery  16
						.
					 Superior palpebral nerves  17
						.
					 Lacrimal duct  18
						.
					 Lacrimal lake  19
						.
					 Medial ocular angle


Dissection of left orbit from an anterior approach
										 Orbital septum; tarsal plates; insertion of levator palpebrae superioris muscle
										The aponeurosis of the levator palpebrae superioris muscle has been partially elevated to illustrate its insertion (18) into the anterior surface of the tarsus. Laterally the aponeurosis has been reflected (16) to expose the tarsal muscle (17), a layer of smooth muscle which extends between the superior margin of the tarsal plate and the deep surface of the aponeurosis of the levator palpebrae muscle. This layer is known as M|ller's muscle.

														 1
						.
					 Corrugator supercilii muscle  2
						.
					 Supraorbital nerve  3
						.
					 Supratrochlear nerve  4
						.
					 Infratrochlear nerve  5
						.
					 Angular vein  6
						.
					 Middle palpebral artery (cut across)  7
						.
					 Dorsal nasal artery emerging from orbit  8
						.
					 Lacrimal part of orbicularis oculi muscle (cut across)  9
						.
					 Medial palpebral ligament  10
						.
					 Small artery in periosteum  11
						.
					 Origin of inferior portion of orbicularis oculi muscle  12
						.
					 Angular head of levator labii superioris muscle  13
						.
					 Branches of facial nerve which supply above muscle  14
						.
					 Supraorbital margin and zygomatico-orbital artery  15
						.
					 Orbital septum  16
						.
					 Aponeurosis of levator palpebrae superioris muscle  17
						.
					 Superior tarsal muscle (muscle of Müller)  18
						.
					 Insertion of aponeurosis of levator palpebrae superioris muscle into superior tarsus  19
						.
					 Superior palpebral nerve  20
						.
					 Superior tarsus (Meibomian glands visible)  21
						.
					 Lacrimal nerve and artery  22
						.
					 Inferior tarsus  23
						.
					 Fat beneath orbicularis oculi muscle  24
						.
					 Branch of facial nerve to orbicularis oculi muscle  25
						.
					 Branch of external maxillary artery which enters orbit  26
						.
					 Inferior palpebral branch of infraorbital nerve


Dissection of left orbit from an anterior approach
										 Branches of trigeminal and facial nerves in orbital and infraorbital regions
										Portions of the orbicularis oculi muscle remain over the medial parts of the eyelids but have been reflected in various ways to show underlying structures. The zygomatic muscle (24) and zygomatic head of the quadratus labii superioris muscle (26) have been partially removed.

														 1
						.
					 Supratrochlear nerve  2
						.
					 Infratrochlear nerve  3
						.
					 Upper pointer: Fascia over superior tarsus Lower pointer: Medial palpebral artery (branch which communicates with supraorbital artery displaced inferiorly)  4
						.
					 Ascending branches of dorsal nasal artery  5
						.
					 Dorsal nasal artery emerging from orbit  6
						.
					 Anastomotic branch between infratrochlear nerve and facial nerve  7
						.
					 Angular vein (divided)  8
						.
					 Orbicularis oculi muscle (reflected upward)  9
						.
					 Angular head of levator labii superioris muscle  10
						.
					 Inferior palpebral branches of infraorbital nerve  11
						.
					 External nasal branch infraorbital nerve  12
						.
					 Alar branch of angular artery  13
						.
					 Infraorbital head of levator labii superioris muscle  14
						.
					 Communications between buccal branches of facial nerve and superior labial branches of infraorbital nerve  15
						.
					 Superior labial branches of infraorbital nerve  16
						.
					 Orbital septum  17
						.
					 Zygomaticotemporal branch zygomatic nerve and zygomatico-orbital artery  18
						.
					 Superior tarsus and lacrimal nerve  19
						.
					 Temporalis muscle  20
						.
					 Layer of fat beneath orbicularis oculi muscle  21
						.
					 Zygomaticofacial branch of zygomatic nerve  22
						.
					 Communication between zygomatic branch facial nerve and inferior palpebral branch of infraorbital nerve  23
						.
					 Malar surface zygomatic bone  24
						.
					 Zygomaticus muscle (cut across)  25
						.
					 Zygomatico-maxillary suture  26
						.
					 Zygomatic head of levator labii superioris muscle  27
						.
					 Buccal branches of facial nerve  28
						.
					 Masseter muscle  29
						.
					 Parotid duct (cut across)  30
						.
					 Buccinator muscle


Dissection of left orbit from an anterior approach
										 Orbital septum; corrugator supercilii muscle
										The orbicularis oculi muscle has been cut away and the connective tissue beneath removed to expose nerves, vessels and fascial structures of the upper lid. The layer of fat (18) originally extended medially between the orbicularis muscle (5) and the orbital septum (16).

														 1
						.
					 Frontalis muscle  2
						.
					 Corrugator supercilii muscle  3
						.
					 Supratrochlear nerve  4
						.
					 Infratrochlear nerve  5
						.
					 Orbicularis oculi muscle (divided and partially removed)  6
						.
					 Medial palpebral artery (note branch which passes superiorly to communicate with supraorbital artery)  7
						.
					 Cut end of lacrimal part orbicularis oculi muscle (superior portion of Horner's muscle)  8
						.
					 Medial palpebral ligament  9
						.
					 Nasal bone (covered by periosteum)  10
						.
					 External nasal branch anterior ethmoidal nerve  11
						.
					 Angular artery and vein  12
						.
					 Frontalis muscle  13
						.
					 Branch supraorbital nerve (communicates in part with temporal branch of facial nerve)  14
						.
					 Frontal nerve (note contribution to palpebral nerves)  15
						.
					 Supraorbital margin of orbit (periosteum intact)  16
						.
					 Orbital septum  17
						.
					 Superior palpebral branches of frontal, supratrochlear, and infratrochlear nerves  18
						.
					 Layer of fat beneath orbicularis oculi muscle  19
						.
					 Aponeurosis of levator palpebrae superioris muscle  20
						.
					 Superior tarsus  21
						.
					 Lacrimal nerve


Dissection of left orbit from an anterior approach
										 Insertion of levator palpebrae superioris muscle
										The orbicularis oculi muscle has been incised vertically and retracted to expose deeper structures in the upper eyelid. The insertion of the aponeurosis of the levator palpebrae superioris muscle into the deep surface of the orbicularis oculi muscle is visible at 16. Some of the fibers of this aponeurosis continue to insert into the skin of the eyelid. A thin layer of fascia covers the tarsal plate (18).

														 1
						.
					 Ascending branches of infratrochlear nerve  2
						.
					 Frontalis muscle  3
						.
					 Descending branch of infratrochlear nerve  4
						.
					 Procerus muscle  5
						.
					 Angular artery and nasal branch of angular vein  6
						.
					 Middle palpebral ligament  7
						.
					 Junction of nasal bone with lateral nasal cartilage  8
						.
					 Transverse part of nasalis muscle (left half reflected)  9
						.
					 Nasal branch of angular artery  10
						.
					 Angular head of levator labii superioris muscle  11
						.
					 External nasal branch of anterior ethmoidal nerve  12
						.
					 Corrugator supercilii muscle  13
						.
					 Layer of fat between orbicularis oculi muscle and orbital septum (not yet exposed)  14
						.
					 Superficial temporal artery  15
						.
					 Orbital part orbicularis oculi muscle (retracted)  16
						.
					 Aponeurosis levator palpebrae superioris muscle  17
						.
					 Palpebral part of orbicularis oculi muscle (retracted)  18
						.
					 Superior tarsus  19
						.
					 Lacrimal nerve  20
						.
					 Margin of skin supporting cilia  21
						.
					 Palpebral part of orbicularis oculi muscle  22
						.
					 Orbital part orbicularis oculi muscle  23
						.
					 Zygomaticus muscle


Dissection of left orbit from an anterior approach
										 Orbicularis oculi muscle; superficial nerves and blood vessels
										The skin and subcutaneous tissue have been removed except for a narrow margin retained at the edges of the eyelids.

														 1
						.
					 Ascending branches of supratrochlear nerve  2
						.
					 Ascending branches of dorsal nasal artery  3
						.
					 Frontalis muscle  4
						.
					 Ascending branches of infratrochlear nerve  5
						.
					 Descending branches of infratrochlear nerve  6
						.
					 Procerus muscle  7
						.
					 Medial palpebral ligament  8
						.
					 Angular artery  9
						.
					 Transverse part of nasalis muscle  10
						.
					 Angular head of levator Iabii superioris muscle  11
						.
					 Nasal branch of angular artery  12
						.
					 Corrugator supercilii muscle (insertion cut off by removal of skin of eyebrow)  13
						.
					 Branch supraorbital nerve  14
						.
					 Temporal branch facial nerve  15
						.
					 Orbital part orbicularis oculi muscle  16
						.
					 Palpebral part of orbicularis oculi muscle  17
						.
					 Skin supporting lashes at lid margin  18
						.
					 Lateral palpebral raphe (ligament)  19
						.
					 Zygomaticofacial branch of zygomatic nerve  20
						.
					 Inferior palpebral branch of infraorbital nerve


Eye and eyelids
										 Surface features, right eye
										The eyelids have been opened more widely than normal to expose the entire extent of the cornea.

														 1
						.
					 Lashes  2
						.
					 Posterior palpebral limbus  3
						.
					 Lirnbus of cornea (annulus conjunctivae located at limbus)  4
						.
					 Sclera and bulbar sheath  5
						.
					 Lateral palpebral commissure  6
						.
					 Lateral ocular angle  7
						.
					 Minor annulus of iris  8
						.
					 Major annulus of iris  9
						.
					 Posterior palpebral limbus  10
						.
					 Anterior palpebral limbus  11
						.
					 Supercilium  12
						.
					 Upper pointer: Superior orbitopalpebral fold Lower pointer: Superior palpebra  13
						.
					 Pupil  14
						.
					 Superior lacrimal papila and puncta  15
						.
					 Lacrimal lake  16
						.
					 Lacrimal caruncle  17
						.
					 Medial palpebral commissure  18
						.
					 Medial ocular angle  19
						.
					 Inferior lacrimal papila (punctum not clearly visible)  20
						.
					 Inferior palpebra


Scalp
										 Superficial nerves and blood vessels of scalp, posterior view
										The superficial layers of the scalp have been dissected to illustrate the distribution of the occipital nerves and artery as well as the underlying musculature. The complex pattern of smaller veins and arteries of the scalp was not demonstrated in this specimen.

														 1
						.
					 Galea aponeurotica  2
						.
					 Occipitalis muscle  3
						.
					 Superior auricular muscle  4
						.
					 Auricle  5
						.
					 Posterior auricular muscle  6
						.
					 Posterior auricular lymph nodes  7
						.
					 Lymph vessel  8
						.
					 Lesser occipital nerve  9
						.
					 Occipital lymph nodes  10
						.
					 Occipital major nerve  11
						.
					 Occipital branch of occipital artery (lateral branch)  12
						.
					 Cutaneous branches of third occipital nerve  13
						.
					 Third occipital nerve  14
						.
					 Superficial fascia  15
						.
					 Superficial fascia  16
						.
					 Scalp  17
						.
					 Occipital branch of occipital artery (medial branch)


Scalp
										 Superficial nerves and blood vessels of scalp, anterolateral view
										Arteries, veins and nerves which lie in the tela subcutanea have been exposed. Branches of the supraorbital nerve (1) lie mostly beneath the galea aponeurotica and consequently are exposed only near their terminations.

														 1
						.
					 Branches of supraorbital nerve  2
						.
					 Superficial temporal vein (posterior branch)  3
						.
					 Superficial temporal vein (anterior branch)  4
						.
					 Location of temporalis muscle beneath galea aponeurotica and temporal fascia  5
						.
					 Frontal branch superficial temporal artery  6
						.
					 Parietal branch superficial temporal artery  7
						.
					 Auriculotemporal nerve  8
						.
					 Superficial temporal artery  9
						.
					 Superficial fascia  10
						.
					 Galea aponeurotica  11
						.
					 Frontalis muscle  12
						.
					 Frontal vein  13
						.
					 Frontal artery (supraorbital artery faintly visible beneath frontalis muscle in a parallel, more lateral position)  14
						.
					 Supraorbital vein  15
						.
					 Anastomosis of superficial veins with middle temporal vein  16
						.
					 Angular vein  17
						.
					 Superior tarsus and orbicularis oculi muscle (cut away)


Floor of cranial cavity
										 Structures inferior to left middle cranial fossa (continued); maxillary and mandibular nerves
										Structures lying within the pterygopalatine, infratemporal and temporal fossae have been dissected. The bone of the lateral wall of the orbit has been cut away but smooth muscle bridging the inferior orbital fissure (8) has been left in situ. The anterior (15) and posterior (17) deep temporal nerves are shown as they pass into the temporal muscle (20). The masseteric nerve (18) passes laterally across the external pterygoid muscle (16) to enter the mandibular notch. An articular branch of this nerve is visible. (18, lower pointer). Other dissections of branches of the mandibular nerve to the muscles of mastication are to be found in 64-7 ff.

														 1
						.
					 Dura mater  2
						.
					 Upper pointer: Mucosal lining of sphenoid sinus Lower pointer: Olfactory bulb  3
						.
					 Upper pointer: Ophthalmic artery Lower pointer: Optic nerve (II)  4
						.
					 Oculomotor nerve (III)  5
						.
					 Ophthalmic nerve (VI)  6
						.
					 Periorbita  7
						.
					 Maxillary nerve passing through foramen rotundum  8
						.
					 Upper pointer: Orbital muscle (smooth muscle within inferior orbital fissure) Lower pointer: Inferior part of orbit  9
						.
					 Lateral rectus muscle  10
						.
					 Zygomatic nerve  11
						.
					 Pterygopalatine fossa  12
						.
					 Superior posterior alveolar branches superior alveolar nerves  13
						.
					 Infraorbital artery  14
						.
					 Pterygoid venous plexus (partially removed)  15
						.
					 Deep temporal nerve anterior  16
						.
					 External pterygoid muscle (superior fascicle)  17
						.
					 Deep temporal nerve posterior  18
						.
					 Upper pointer: Masseteric nerve Lower pointer: Articular branch of masseteric nerve  19
						.
					 Middle meningeal artery (anterior branch)  20
						.
					 Temporalis muscle (medial surface)  21
						.
					 Upper pointer: Hypophysis (midsagittal section) Lower pointer: Sella turcica (bone removed anteriorly to display sphenoid sinus)  22
						.
					 Upper pointer: Abducens nerve (VI) Lower pointer: Internal carotid artery  23
						.
					 Major portion of trigeminal nerve (V)  24
						.
					 Internal carotid nerve plexus  25
						.
					 Semilunar ganglion and minor portion trigeminal nerve  26
						.
					 Upper pointer: Sphenoid bone (cut across at junction of body and pterygoid process) Lower pointer: Venous plexus of foramen ovale (bony wall removed)  27
						.
					 Major superficial petrosal nerve  28
						.
					 Upper pointer: Lesser superficial petrosal nerve Lower pointer: Middle meningeal artery (cut across)  29
						.
					 Upper pointer: Facial nerve (VII) (within internal acoustic meatus) Lower pointer: Cochlea  30
						.
					 Upper pointer: Vestibulocochlear nerve (VIII) (vestibular part) Lower pointer: Vestibule  31
						.
					 Geniculate ganglion facial nerve  32
						.
					 Chorda tympani  33
						.
					 Semicircular canal lateral  34
						.
					 Incus  35
						.
					 Tympanic cavity  36
						.
					 Upper pointer: Capitulum condyloid process of mandible Lower pointer: Articular disc of mandible (partially cut away)  37
						.
					 External acoustic meatus


Floor of cranial cavity
										 Structures inferior to left middle cranial fossa, superior view
										The bone has been cut away from central and lateral regions of the middle cranial fossa. The cavities of the left middle and inner ear have been opened.

														 1
						.
					 Mucosa of sphenoid sinus (bony wall removed)  2
						.
					 Optic nerve (II)  3
						.
					 Periorbita (in areas adjacent to this the bony roof of the orbit has been partially cut away to reveal an extensive network of veins within the substance of the bone)  4
						.
					 Oculomotor nerve (III) and trochlear nerve (IV)  5
						.
					 Maxillary nerve (V2) passing into foramen rotundum  6
						.
					 Ophthalmic nerve (Vl)  7
						.
					 Greater wing of sphenoid (cut across near junction with body of sphenoid bone)  8
						.
					 Mandibular nerve (V3) passing into foramen ovale  9
						.
					 Periosteum covering contents of pterygopalatine fossa (exposed by cutting away overlying bone)  10
						.
					 Periosteum of infratemporal fossa (fibers of origin of external pterygoid muscle are visible)  11
						.
					 Foramen ovale (periosteal lining intact)  12
						.
					 Thickened margin of dura mater along crest which separates anterior from middle cranial fossa  13
						.
					 Middle meningeal artery  14
						.
					 Temporalis muscle  15
						.
					 Sella turcica  16
						.
					 Internal carotid artery  17
						.
					 Trigeminal nerve (V)  18
						.
					 Major superficial petrous nerve and middle meningeal artery  19
						.
					 Cochlea  20
						.
					 Facial nerve (VII) (pointer at junction of internal acoustic meatus and facial canal)  21
						.
					 Upper pointer: Vestibule Lower pointer: Semicircular canal (lateral)  22
						.
					 Upper pointer: Anterior part of tympanic cavity Lower pointer: Incus  23
						.
					 Articular disc of mandible  24
						.
					 Tympanic antrum  25
						.
					 Periosteum of external acoustic meatus


Floor of cranial cavity
										 Middle cranial fossa; dissection of left cavernous sinus (continued); internal carotid artery; hypophysis sectioned in midsagittal plane
										Communicating branches between the sympathetic plexus on the internal carotid artery and the abducens nerve have been exposed and the ophthalmic sympathetic nerve (2) traced onto the ophthalmic artery. The course of the internal carotid artery (13) is seen in relation to the sella turcica (12).

														 1
						.
					 Hypophyseal branch of internal carotid artery right  2
						.
					 Ophthalmic artery and ophthalmic nerve plexus  3
						.
					 Optic nerve (II) (anterior clinoid process cut away)  4
						.
					 Upper pointer: Oculomotor nerve (III) Lower pointer: Trochlear nerve (IV)  5
						.
					 Ophthalmic nerve entering superior orbital fissure  6
						.
					 Lacrimal nerve  7
						.
					 Superior ophthalmic vein (bone of lateral wall of orbit cut away)  8
						.
					 Posterior clinoid process  9
						.
					 Upper pointer: Infundibulum Lower pointer: Posterior pituitary (hypophysis)  10
						.
					 Anterior pituitary (hypophysis)  11
						.
					 Basilar venous plexus  12
						.
					 Sella turcica (dura mater stripped away posteriorly to expose small veins and artery)  13
						.
					 Internal carotid artery  14
						.
					 Abducens nerve (VI)  15
						.
					 Cavernous nerve plexus  16
						.
					 Branch of internal carotid artery to semilunar ganglion and meninges of cavernous sinus  17
						.
					 Sphenopetrosal ligament  18
						.
					 Semilunar ganglion


Floor of cranial cavity
										 Middle cranial fossa; dissection of left cavernous sinus (continued); portio minor of trigeminal nerve; abducens nerve; carotid plexus
										The trigeminal nerve has been turned laterally to expose its motor root (18), the fibrous tissue partially closing the foramen lacerum (16), and the relations of the carotid artery and cavernous plexus of nerves (14).

														 1
						.
					 Circular sinus and hypophysis  2
						.
					 Internal carotid artery and optic nerve (II)  3
						.
					 Internal carotid artery within cavernous sinus  4
						.
					 Oculomotor nerve (III)  5
						.
					 Trochlear nerve (IV)  6
						.
					 Upper pointer: Branch of internal carotid artery to meninges and semilunar ganglion Lower pointer: Communication between internal carotid sympathetic plexus and ophthalmic nerve  7
						.
					 Ophthalmic nerve (V1)  8
						.
					 Cavernous sinus near junction with superior ophthalmic vein  9
						.
					 Maxillary nerve (V2)  10
						.
					 Posterior longitudinal ligament  11
						.
					 Posterior clinoid process  12
						.
					 Petroclinoid ligament  13
						.
					 Upper pointer: Abducens nerve (VI) Lower pointer: Apex of pyramid  14
						.
					 Cavernous nerve plexus  15
						.
					 Dura mater forming medial wall of trigeminal (Meckel's) cave  16
						.
					 Dura mater bridging across sphenopetrous fissure  17
						.
					 Semilunar ganglion  18
						.
					 Minor portion trigeminal nerve (V)  19
						.
					 Greater superficial petrosal nerve  20
						.
					 Major portion of trigeminal nerve (V) (reflected laterally)  21
						.
					 Lesser superficial petrosal nerve


Floor of cranial cavity
										 Middle cranial fossa; dissection of left cavernous sinus (continued); semilunar ganglion; petrosal nerves
										More veins have been cut away to expose the three divisions of the trigeminal nerve (8,10,20) the abducens nerve (14) and the petrosal nerves (19,21).

														 1
						.
					 Circular sinus  2
						.
					 Tuberculum sellae  3
						.
					 Oculomotor nerve (III)  4
						.
					 Band of dura mater extending between anterior and posterior clinoid processes  5
						.
					 Internal carotid artery  6
						.
					 Optic foramen  7
						.
					 Trochlear nerve (IV)  8
						.
					 Ophthalmic nerve (V1)  9
						.
					 Superior orbital fissure  10
						.
					 Maxillary nerve (V2) entering foramen rotundum  11
						.
					 Basilar venous plexus and posterior clinoid process  12
						.
					 Posterior longitudinal ligament (cut off)  13
						.
					 Ligamentous band of dura mater extending from tip of petrous part of temporal bone to sphenoid bone (petrodinoid ligament)  14
						.
					 Abducens nerve (VI)  15
						.
					 Major portion of trigeminal nerve (V)  16
						.
					 Meckel's cave  17
						.
					 Filament of cavernous nerve plexus  18
						.
					 Semilunar ganglion (trigeminal)  19
						.
					 Upper pointer: Thin lamina of bone which covers carotid canal Lower pointer: Major superficial petrous nerve  20
						.
					 Mandibular nerve (V3)  21
						.
					 Lesser superficial petrosal nerve  22
						.
					 Middle meningeal artery (cut off)


Floor of cranial cavity
										 Middle cranial fossa; dissection of left cavernous sinus, superolateral view
										The dura mater to the left of the midline has been cut away. Structures which pass through the cavernous sinus are partially exposed. The continuity of the venous spaces in this sinus with those in the circular and basilar sinuses is illustrated. Latex-filled veins have been cleared away from the internal carotid artery at 15.

														 1
						.
					 Internal carotid artery right and optic nerve  2
						.
					 Anterior clinoid process  3
						.
					 Position of superior orbital fissure  4
						.
					 Trochlear nerve (IV)  5
						.
					 Ophthalmic nerve (V)  6
						.
					 Cavernous sinus  7
						.
					 Inner surface of an unusual venous sinus which passed posteriorly into the superior petrosal sinus (see also Section I, 42)  8
						.
					 Middle cranial fossa  9
						.
					 Branch of internal carotid artery to hypophysis  10
						.
					 Trigeminal nerve (V) entering Meckel's cave  11
						.
					 Circular sinus and infundibulum  12
						.
					 Dorsum sellae  13
						.
					 Oculomotor nerve (III) and posterior clinoid process  14
						.
					 Basilar venous plexus  15
						.
					 Internal carotid artery (cavernous part)  16
						.
					 Cavernous nerve plexus  17
						.
					 Area of communication of cavernous nerve plexus with oculomotor, trochlear and ophthalmic nerves  18
						.
					 Dura mater enclosing trigeminal nerve  19
						.
					 Greater part of trigeminal nerve (V)  20
						.
					 Cut edge of tentorium cerebelli  21
						.
					 Semilunar ganglion (trigeminal)


Floor of cranial cavity
										 Structures in region of sella turcica; origin of ophthalmic arteries, superior view
										The optic nerves have been transected and elevated. To the left of the midline the dura mater has been cut away to display the cavernous sinus (8), basilar plexus of veins (11) and dorsum sellae (20).

														 1
						.
					 Olfactory tract  2
						.
					 Optic nerve (II) (elevated)  3
						.
					 Ophthalmic artery and anterior clinoid process  4
						.
					 Diaphragm of sella  5
						.
					 Ophthalmic nerve (VI)  6
						.
					 Trochlear nerve (IV)  7
						.
					 Posterior communicating artery and oculomotor nerve (III)  8
						.
					 Cavernous sinus  9
						.
					 Tentorium cerebelli (cut away)  10
						.
					 Semilunar ganglion (trigeminal)  11
						.
					 Basilar venous plexus  12
						.
					 Boundary between anterior and middle cranial fossae  13
						.
					 Arachnoid matter (extending into optic canal)  14
						.
					 Tuberculum sellae  15
						.
					 Branch of internal carotid artery right to hypophysis  16
						.
					 Hypophysis (visible through diaphragmatic foramen)  17
						.
					 Infundibulum (cut across)  18
						.
					 Oculomotor nerve entering cavernous sinus (note sac-like eversion of dura mater similar to Meckel's cave)  19
						.
					 Posterior clinoid process  20
						.
					 Dorsum sellae  21
						.
					 Orifice in margin of tentorium cerebelli to accommodate trochlear nerve (IV)


Floor of cranial cavity
										 Structures inferior to anterior and middle cranial fossae; orbit and sinuses opened
										Views of the dissection of the contents of the orbit from this approach are found in 54-1 ff.

														 1
						.
					 Frontal sinus  2
						.
					 Infundibulum leading into nasofrontal duct  3
						.
					 Upper pointer: Frontal nerve Lower pointer: Levator palpebrae superioris  4
						.
					 Posterior ethmoidal nerve (usually a branch of the ophthalmic nerve in this case the fibers accompany the trochlear nerve)  5
						.
					 Posterior ethmoidal artery in posterior ethmoidal foramen  6
						.
					 Lacrimal nerve and superior ophthalmic vein  7
						.
					 Periorbita (area of fusion with common annular tendon)  8
						.
					 Maxillary nerve (V2)  9
						.
					 Trochlear nerve (IV)  10
						.
					 Oculomotor nerve (III)  11
						.
					 Abducens nerve (VI)  12
						.
					 Vidian nerve of pterygoid canal (below floor of sphenoid sinus)  13
						.
					 Semilunar ganglion (trigeminal)  14
						.
					 Mandibular nerve (V3)  15
						.
					 Cavernous nerve plexus  16
						.
					 Ethmoidal cell (anterior)  17
						.
					 Anterior ethmoidal nerve  18
						.
					 Cribriform plate ethmoid bone  19
						.
					 Anterior ethmoidal artery (in anterior ethmoidal foramen)  20
						.
					 Ethmoidal cell (posterior)  21
						.
					 Posterior ethmoidal vein  22
						.
					 Upper pointer: Aperture of sphenoid sinus Lower pointer: Sphenoid sinus  23
						.
					 Optic nerve (ll)  24
						.
					 Internal carotid artery  25
						.
					 Upper pointer: Circular sinus Lower pointer: Hypophysis (left half removed)  26
						.
					 Sella turcica  27
						.
					 Dorsum sellae  28
						.
					 Basilar venous plexus


Floor of cranial cavity
										 Structures inferior to anterior and middle cranial fossae
										Bone has been removed to expose structures underlying the floor of the anterior part of the cranial vault.

														 1
						.
					 Mucosa of frontal sinus  2
						.
					 Orbital part of frontal bone  3
						.
					 Position of anterior ethmoidal foramen (opened)  4
						.
					 Olfactory bulb  5
						.
					 Periorbita  6
						.
					 Mucosa of ethmoidal cell (posterior)  7
						.
					 Position of maxillary sinus (in depths of view)  8
						.
					 Maxillary nerve (V)  9
						.
					 Oculomotor nerve (III)  10
						.
					 Part of pterygoid venous plexus  11
						.
					 Deep temporal nerve posterior  12
						.
					 Ophthalmic nerve (VI)  13
						.
					 External pterygoid muscle  14
						.
					 Abducens nerve (VI)  15
						.
					 Crista galli  16
						.
					 Mucosa of sphenoid sinus  17
						.
					 Middle cranial fossa  18
						.
					 Optic nerves (II)  19
						.
					 Internal carotid artery (right and left)  20
						.
					 Hypophysis (left half cut away)  21
						.
					 Sella turcica  22
						.
					 Dorsum sellae


Floor of cranial cavity
										 Anterior cranial fossa; terminal nerve; olfactory bulb and tract, superior view
										The dura mater has been removed from the bone to the left of the midline except in the region of the cribriform plate. Ther terminal nerve (3) was cut at the point of its penetration through the arachnoid membrane covering the gyrus rectus on the inferior surface of the frontal lobe.

														 1
						.
					 Position of foramen caecum frontal bone  2
						.
					 Anterior meningeal artery  3
						.
					 Terminal nerve  4
						.
					 Olfactory bulb (several of the numerous olfactory nerves are visible passing from the bulb into the cribriform plate)  5
						.
					 Olfactory tract  6
						.
					 Lesser wing sphenoid bone  7
						.
					 Anterior clinoid process  8
						.
					 Upper pointer: Crista galli Lower pointer: Cut edge of falx cerebri  9
						.
					 Dura mater covering orbital part of frontal bone  10
						.
					 Optic nerves (ll)  11
						.
					 Left pointer: Ophthalmic artery Right pointer: Internal carotid artery


Floor of cranial cavity
										 Cranial fossae and sites of exit of cranial nerves, posterior view
										The dura mater has been stripped from the left half of the posterior fossa to open venous sinuses. Views of the atlantooccipital ligaments are to be found in 80-2 ff.

														 1
						.
					 Upper pointer: Olfactory tract Lower pointer: Optic nerve (II)  2
						.
					 Sella turcica  3
						.
					 Left pointer: Venous sinus (unnamed) Middle pointer: Trochlear nerve (IV) Right pointer: Oculomotor nerve (III)  4
						.
					 Upper pointer: Trigeminal nerve (V) Lower pointer: Superior petrosal sinus  5
						.
					 Upper pointer: Facial nerve (VII) (intermediate nerve lies just below pointer) Lower pointer: Acoustic nerve (VllI)  6
						.
					 Glossopharyngeal nerve (IX)  7
						.
					 Vagus nerve (X)  8
						.
					 Accessory nerve (XI)  9
						.
					 Transverse sinus (sigmoid part)  10
						.
					 Vertebral artery  11
						.
					 Occipital artery (retracted laterally)  12
						.
					 Dorsal root cervical nerve II  13
						.
					 Anterior cranial fossa  14
						.
					 Lesser wing sphenoid bone (covered by dura mater)  15
						.
					 Upper pointer: Middle meningeal artery Lower pointer: Middle cranial fossa  16
						.
					 Basilar venous plexus (connecting inferiorly with inferior petrosal sinus)  17
						.
					 Abducens nerve (VI)  18
						.
					 Posterior cranial fossa  19
						.
					 Hypoglossal nerve (Xll)  20
						.
					 Posterior meningeal artery  21
						.
					 Spinal cord  22
						.
					 Arch of axis


General orientation views of dissection
										 Midsagittal section of head and neck, right lateral view
										A close-up view of the larynx of this specimen is to be found in 83-6.

														 1
						.
					 Scalp  2
						.
					 Calvaria  3
						.
					 Upper pointer: Falx cerebri Lower pointer: Superior sagittal sinus  4
						.
					 Right pointer: Great cerebal vein Left pointer: Straight sinus  5
						.
					 Upper pointer: Mesencephalon Lower pointer: Cerebral aqueduct  6
						.
					 Confluence of the sinuses  7
						.
					 Upper pointer: Fourth ventricle Lower pointer: Pons  8
						.
					 Cerebellum  9
						.
					 Medulla oblongata  10
						.
					 Margins of foramen magnum  11
						.
					 Cerebellomedullary cistern (cisterna magna)  12
						.
					 Posterior arch atlas  13
						.
					 Upper pointer: Anterior arch atlas Lower pointer: Dens axis  14
						.
					 Spinous process axis  15
						.
					 Intervertebral disc  16
						.
					 Spinal cord  17
						.
					 Laryngeal part of pharynx  18
						.
					 Left pointer: Fornix Right pointer: Corpus callosum  19
						.
					 Upper pointer: Third ventricle Lower pointer: Interpeduncular cistern  20
						.
					 Upper pointer: Optic chiasm Lower pointer: Hypophysis  21
						.
					 Frontal sinus  22
						.
					 Sphenoid sinus  23
						.
					 Nasal cavity  24
						.
					 Nasal septum (partially cut away)  25
						.
					 Upper pointer: Bony auditory tube Lower pointer: Nasal part pharynx  26
						.
					 Hard palate  27
						.
					 Upper pointer: Oral cavity Lower pointer: Soft palate  28
						.
					 Tongue  29
						.
					 Oral part pharynx  30
						.
					 Mandible  31
						.
					 Geniohyoid muscle  32
						.
					 Hyoid bone  33
						.
					 Epiglottis  34
						.
					 Larynx (plica vocalis)  35
						.
					 Trachea


Exploration of the brain from its basal aspect
										 Ansa lenticularis
										This view is a close-up of the previous one but the specimen is now turned at right angles so that the midline is at the bottom. Details of the ansa lenticularis (13) in its course around the medial edge of the cerebral peduncle are revealed. Some fibers of this group are also seen as they pass inward between fascicles of the peduncle and these join others above the peduncle to form the fasciculus lenticularis (H2 field of Forel) in the subthalamic region.

														 1
						.
					 Lateral geniculate body  2
						.
					 Optic tract (cut and retracted posteriorly)  3
						.
					 Cerebral peduncle  4
						.
					 Posterior cerebral artery (cut across)  5
						.
					 Pons  6
						.
					 Superior cerebellar artery  7
						.
					 Oculomotor nerve (III)  8
						.
					 Mamillary body  9
						.
					 Putamen  10
						.
					 Internal capsule  11
						.
					 Globus pallidus (external division)  12
						.
					 Anterior commissure  13
						.
					 Ansa lenticularis  14
						.
					 Artery of Heubner  15
						.
					 Diagonal band of Broca  16
						.
					 Radiating fibers of rostral lamina of corpus callosum  17
						.
					 Anterior perforated substance  18
						.
					 Anterior cerebral artery (cut across)  19
						.
					 Olfactory trigone  20
						.
					 Optic nerve (II)


Exploration of the brain from its basal aspect
										 Relations of internal capsule, lentiform nucleus and ansa lenticularis
										The anterior half of the lentiform nucleus has been cut away to expose the internal capsule. Broken ends of fibres seen protruding from the capsule joined the external medullary lamina which is visible on the cut surface of the lentiform nucleus. The upper part of the external capsule remains in place. The mass of fibers (15) passing across the cerebral peduncle consists mainly of efferent fibers from the medial division of the globus pallidus which loop around the medial margin of the peduncle. Some of these fibers penetrate between bundles of the peduncle (or internal capsule) to form the fasciculus lenticularis internally. The optic tract is divided and turned posteriorly.

														 1
						.
					 Frontal part of operculum  2
						.
					 Recurrent artery of Heubner  3
						.
					 Middle cerebral artery (retracted laterally)  4
						.
					 External capsule (cut across)  5
						.
					 Internal capsule  6
						.
					 Superior longitudinal fasciculus  7
						.
					 Lentiform nucleus (putamen)  8
						.
					 Geniculocalcarine tract  9
						.
					 Head of caudate nucleus  10
						.
					 Fibers radiating from rostral lamina of corpus callosum  11
						.
					 Orbital gyrus (dissected)  12
						.
					 Olfactory tract  13
						.
					 Optic chiasm  14
						.
					 Posterior part of anterior commissure  15
						.
					 Ansa lenticularis  16
						.
					 Cerebral peduncle  17
						.
					 Optic tract (retracted posteriorly)  18
						.
					 Posterior cerebral artery (cut across)  19
						.
					 Pons


Exploration of the brain from its basal aspect
										 External capsule, lentiform nucleus and deeper course of striate arteries
										The main trunk of the middle cerebral artery has been retracted far laterally, the medullary center of the insula removed and the claustrum scraped away. The external capsule has been partially removed, the remaining portion being turned laterally to expose the lentiform nucleus. The course of the lateral striate arteries into the lentiform nucleus is visible.

														 1
						.
					 Orbital gyrus  2
						.
					 Middle cerebral artery (divided and turned laterally)  3
						.
					 Superior longitudinal fasciculus  4
						.
					 Frontal part of operculum  5
						.
					 External capsule (reflected laterally)  6
						.
					 Lentiform nucleus (putamen)  7
						.
					 Lateral striate artery  8
						.
					 Amygdaloid nucleus (partially removed)  9
						.
					 Stria terminalis  10
						.
					 Geniculocalcarine tract (cut across close to its origin from lateral geniculate body)  11
						.
					 Inferior occipitofrontal fasciculus  12
						.
					 Longitudinal fissure (cerebral)  13
						.
					 Olfactory trigone  14
						.
					 Recurrent branch of anterior cerebral artery  15
						.
					 Anterior perforated substance  16
						.
					 Tuber cinereum  17
						.
					 Choroidal artery (anterior)  18
						.
					 Interpeduncular fossa  19
						.
					 Posterior cerebral artery (divided)  20
						.
					 Hippocampus (cut across)


Exploration of the brain from its basal aspect
										 Medullary substance of insula
										The cortex of the insula has been removed to expose the medullary substance immediately beneath it. The brain is now viewed from a slightly different angle but the configuration of branches of the middle cerebral artery is easily compared with the previous stage of dissection. The temporal lobe is not cut away further nor is the inferior occipitofrontal bundle altered. The choroid plexus is removed from the opened inferior horn of the lateral ventricle.

														 1
						.
					 Meninges (at former limit of temporal lobe)  2
						.
					 Medullary substance of insula  3
						.
					 Uncinate fasciculus (cut across)  4
						.
					 Frontal part of operculum  5
						.
					 Roof of inferior horn, lateral ventricle  6
						.
					 Lateral geniculate body  7
						.
					 Choroidal branch of posterior cerebral artery  8
						.
					 Hippocampus  9
						.
					 Middle cerebral artery  10
						.
					 Optic tract  11
						.
					 Inferior occipitofrontal fasciculus  12
						.
					 Cerebellum (cut across)


Exploration of the brain from its basal aspect
										 Inferior occipitofrontal fasciculus, limen insulae and arteries of choroid plexus
										More tissue of the temporal lobe and hippocampus has been removed. The relation of the inferior occipitofrontal fasciculus to both the insula and the inferior horn of the lateral ventricle is demonstrated. The uncinate bundle is cut off as it courses deep to the limen insulae. The anterior choroidal artery is seen as it penetrates the choroid plexus of the inferior horn of the lateral ventricle. The choroidal branch of the posterior cerebral artery is visible as its passes across the inferior surface of the lateral geniculate body.

														 1
						.
					 Middle cerebral artery  2
						.
					 Limen insulae  3
						.
					 Uncinate fasciculus (cut across)  4
						.
					 Inferior occipitofrontal fasciculus  5
						.
					 Long insular gyrus  6
						.
					 Amygdaloid nucleus  7
						.
					 Choroidal artery (anterior)  8
						.
					 Inferior horn of lateral ventricle  9
						.
					 Frontal part of operculum  10
						.
					 Choroid plexus  11
						.
					 Choroidal branch of posterior cerebral artery  12
						.
					 Lateral geniculate body  13
						.
					 Hippocampus (cut across)  14
						.
					 Fusiform gyrus  15
						.
					 Internal carotid artery  16
						.
					 Optic tract  17
						.
					 Posterior communicating artery  18
						.
					 Cerebral peduncle  19
						.
					 Posterior cerebral artery  20
						.
					 Trigeminal nerve (V)  21
						.
					 Pons


Exploration of the brain from its basal aspect
										 Contents of lateral fissure exposed by partial resection of temporal lobe
										The temporal lobe has been further cut away to expose the insula, the frontal operculum and branches of the middle cerebral artery lying in the lateral fissure. The arachnoid membrane and pia mater which covered a part of the resected temporal lobe are left in situ. The hypophysis has been removed.

														 1
						.
					 Meninges (arachnoid and pia mater encephali)  2
						.
					 Orbitofrontal branch of middle cerebral artery  3
						.
					 Anterior temporal artery  4
						.
					 Insula  5
						.
					 Frontal part of operculum  6
						.
					 Middle cerebral artery  7
						.
					 Striate artery  8
						.
					 Artery of precentral sulcus  9
						.
					 Inferior occipitofrontal fasciculus (cut obliquely)  10
						.
					 Inferior horn of lateral ventricle  11
						.
					 Tapetum  12
						.
					 Medial temporal gyrus  13
						.
					 Inferior temporal gyrus  14
						.
					 Inferior temporal sulcus  15
						.
					 Fusiform gyrus  16
						.
					 Orbital branch of anterior cerebral artery  17
						.
					 Olfactory tract  18
						.
					 Choroidal artery (anterior)  19
						.
					 Optic tract  20
						.
					 Mamillary body  21
						.
					 Cerebral peduncle  22
						.
					 Hippocampus (cut across)  23
						.
					 Pons  24
						.
					 Trigeminal nerve (V)  25
						.
					 Collateral fissure  26
						.
					 Basilar artery  27
						.
					 Olive


Exploration of the brain from its basal aspect
										 Close-up view of arteries entering anterior perforated substance
										The hypophysis and optic chiasm are retracted toward the pons. The right posterior communicating artery (17) is divided and the internal carotid artery displaced forward to demonstrate the recurrent branch of the anterior cerebral artery (artery of Heubner) and the perforating branches of the anterior choroidal artery.

														 1
						.
					 Orbital gyrus  2
						.
					 Middle cerebral artery  3
						.
					 Lateral striate branch of middle cerebral artery  4
						.
					 Entrance to insula  5
						.
					 Anterior perforated substance  6
						.
					 Choroidal artery (anterior)  7
						.
					 Amygdaloid nucleus  8
						.
					 Oculomotor nerve (III)  9
						.
					 Cerebral peduncle  10
						.
					 Choroid plexus lateral ventricle  11
						.
					 Hippocampus  12
						.
					 Olfactory tract  13
						.
					 Longitudinal fissure (cerebral)  14
						.
					 Straight gyrus  15
						.
					 Orbital branch of anterior cerebral artery  16
						.
					 Internal carotid artery  17
						.
					 Posterior communicating artery (divided)  18
						.
					 Anterior cerebral artery  19
						.
					 Recurrent artery of Heubner  20
						.
					 Optic chiasm  21
						.
					 Optic nerve (II)  22
						.
					 Optic tract  23
						.
					 Hypophysis  24
						.
					 Pons  25
						.
					 Basilar artery


General orientation views of dissection
										 Deep dissection of head and neck, left lateral view; brain removed
										The left half of the calvaria has been removed and the cerebral hemispheres cut away to expose the left optic tract (2) encircling the cerebral peduncle (26). The close-up views which illustrate more details of this dissection are to be found as follows

														 1
						.
					 Falx cerebri  2
						.
					 Optic tract  3
						.
					 Lateral rectus muscle (lateral wall of orbit cut away)  4
						.
					 Superior tarsus  5
						.
					 Ophthalmic nerve in cavernous sinus  6
						.
					 Upper pointer: Maxillary nerve Lower pointer: Sphenopalatine artery  7
						.
					 Nasal cavity (opened)  8
						.
					 Upper pointer: Buccal nerve (crossing internal maxillary artery) Lower pointer: Lateral plate of pterygoid process  9
						.
					 Maxilla (partially cut away)  10
						.
					 Buccinator muscle (cut away to expose tongue)  11
						.
					 Upper pointer: Tongue Lower pointer: Medial incisor (sectioned)  12
						.
					 Sublingual gland  13
						.
					 Mandible (cut across)  14
						.
					 Mylohyoid muscle  15
						.
					 Anterior belly digastric muscle  16
						.
					 Common carotid artery  17
						.
					 Thyroid cartilage  18
						.
					 Inferior pharyngeal constrictor muscle  19
						.
					 Cricothyroid muscle  20
						.
					 Vagus nerve (X)  21
						.
					 Trachea  22
						.
					 Common carotid artery (cut across)  23
						.
					 Sternoclavicular articulation  24
						.
					 Junction of tentorium cerebelli with falx cerebri  25
						.
					 Lambdoidal suture  26
						.
					 Upper pointer: Lateral geniculate body Lower pointer: Base of peduncles  27
						.
					 Semilunar ganglion (CN V)  28
						.
					 Upper pointer: External acoustic meatus (auricle removed) Lower pointer: Mastoid cells (dissected)  29
						.
					 Auriculotemporal nerve  30
						.
					 Facial nerve (VII)  31
						.
					 External carotid artery  32
						.
					 Posterior belly of digastric muscle  33
						.
					 Upper pointer: Inferior alveolar nerve Lower pointer: Lingual nerve  34
						.
					 Internal pterygoid muscle  35
						.
					 Hypoglossal nerve (XII)  36
						.
					 Longus capitis muscle  37
						.
					 Cervical nerve IV  38
						.
					 Longissimus cervicis muscle  39
						.
					 Anterior scalene muscle  40
						.
					 Middle scalene muscle  41
						.
					 Posterior scalene muscle  42
						.
					 Brachial plexus (cut across through roots)  43
						.
					 Subclavian artery (cut off)  44
						.
					 Rib I (periosteum removed to show small area of rib)


General orientation views of dissection
										 Deep facial dissection, left lateral view; internal maxillary artery
										The bony lateral wall of the orbit has been completely removed except for a narrow bridge at the orbital margin. The dura mater of the anterior (4) the middle (6) cranial fossae is visible through openings cut in the skull. The internal maxillary artery (11) has been exposed by removal of much of the left half of the mandible as well as the temporal and internal pterygoid muscles. Close-up views which illustrate more details of this dissection are to be found as follows

														 1
						.
					 Coronal suture  2
						.
					 Superior temporal line  3
						.
					 Frontal bone  4
						.
					 Dura mater encephali (in anterior cranial fossa)  5
						.
					 Superior lacrimal gland  6
						.
					 Middle meningeal artery and dura mater encephali (in middle cranial fossa)  7
						.
					 Lateral rectus muscle  8
						.
					 Zygomatic nerve  9
						.
					 Zygomatic bone (partially cut away)  10
						.
					 Buccal nerve  11
						.
					 Internal maxillary artery (note plexus venosus pterygoideus)  12
						.
					 Auriculotemporal nerve  13
						.
					 Internal pterygoid muscle (area for insertion on angle of mandible appears as broad crescentic white portion at inferior end of muscle)  14
						.
					 Buccinator muscle  15
						.
					 Mental nerve (emerging from mental foramen)  16
						.
					 Mandible  17
						.
					 Anterior belly digastric muscle  18
						.
					 Mylohyoid muscle (reflected laterally)  19
						.
					 Thyroid cartilage  20
						.
					 Parietal bone  21
						.
					 Area of origin of temporalis muscle  22
						.
					 Middle temporal artery  23
						.
					 Occipital bone (squamous part)  24
						.
					 Lambdoidal suture and intersutural bone  25
						.
					 Upper pointer: Cut end of zygomatic arch Lower pointer: Articular disc for mandible  26
						.
					 Upper pointer: External acoustic meatus Lower pointer: Styloid process temporal bone  27
						.
					 Mastoid cells (cut open)  28
						.
					 Splenius capitis muscle  29
						.
					 Facial nerve (VII)  30
						.
					 Posterior belly of digastric muscle  31
						.
					 Mylohyoid nerve  32
						.
					 Lingual nerve (pointer in area of submandibular ganglion)  33
						.
					 Common facial vein  34
						.
					 Hypoglossal nerve (Xll)  35
						.
					 Internal jugular vein  36
						.
					 Common carotid artery (pointer at bifurcation)  37
						.
					 Anterior scalene muscle


General orientation views of dissection
										 Deep facial dissection, lateral view; temporal muscle; course of facial nerve through parotid gland
										The masseter muscle has been completely removed and the zygomatic arch cut away. The parotid gland and duct have been preserved. The superficial part of the gland has been dissected to expose the course of the facial nerve (23) from the stylomastoid foramen through the substance of the gland. The sternocleidomastoid muscle has been cut from its cranial attachments. Close-up views which illustrate more details of this dissection are to be found as follows

														 1
						.
					 Parietal bone  2
						.
					 Coronal suture  3
						.
					 Frontal bone  4
						.
					 Temporalis muscle  5
						.
					 Upper pointer: Cut end of zygomatic arch Lower pointer: Muscle tendon arising from deep surface of zygomatic arch, inserting with temporalis muscle but innervated by a branch of the masseteric nerve  6
						.
					 Zygomatic bone  7
						.
					 Position of coronoid process of mandible  8
						.
					 Attachment of tendon of masseter muscle to zygomatic bone  9
						.
					 Upper pointer: Accessory parotid gland Lower pointer: Parotid duct  10
						.
					 Infraorbital nerve  11
						.
					 Buccinator muscle  12
						.
					 Angle of mandible  13
						.
					 External maxillary artery  14
						.
					 Submandibular gland  15
						.
					 Lambdoidal suture  16
						.
					 Occipitalis muscle  17
						.
					 Occipital branch of posterior auricular nerve  18
						.
					 Superficial temporal artery  19
						.
					 Greater occipital nerve  20
						.
					 Lesser occipital nerve  21
						.
					 Upper pointer: External acoustic meatus Lower pointer: Mastoid process  22
						.
					 Splenius capitis muscle (pointer in area previously covered by sternocleidomastoid muscle)  23
						.
					 Facial nerve (VII) and parotid gland  24
						.
					 Trapezius muscle (cut off)  25
						.
					 Superior deep cervical lymph nodes  26
						.
					 Posterior facial vein  27
						.
					 Accessory nerve (XI)  28
						.
					 Internal jugular vein (visible in opening cut through carotid sheath)