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1733

Fluoroscopic Swallowing Examination:
Radiologic Findings and Analysis of
Their Causes and Pathophysiologic
Mechanisms

Alberto I. Carbo, MD
Melanie Brown, CCC-SLP
Nour Nakrour, MD

Abbreviations: CP = cricopharyngeus, HLC =
hyolaryngeal complex, PES = pharyngoesopha­
geal segment, UES = upper esophageal sphincter

RadioGraphics 2021; 41:1733–1749

https://doi.org/10.1148/rg.2021210051

Content Codes:

From  the  Departments  of  Radiology  (A.I.C.,
N.N.) and Rehabilitation Services (M.B.), Ochs­
ner LSU Health, 1501 Kings Hwy, Shreveport,
LA  71103.  Presented  as  an  education  exhibit
at  the  2020  RSNA  Annual  Meeting.  Received
March 7, 2021; revision requested April 19 and
received May 14; accepted May 23. For this jour­
nal­based SA­CME activity, the authors, editor,
and  reviewers  have  disclosed  no  relevant  rela­
tionships.  Address  correspondence  to A.I.C.
(e­mail: acarbo1396@gmail.com).

©RSNA, 2021

SA-CME LEARNING OBJECTIVES

After completing this journal-based SA-CME
activity, participants will be able to:
	„Discuss the anatomy and imaging
phases of swallowing.

	„Describe abnormalities detected at
fluoroscopic swallowing examination.

	„Correlate the radiologic findings
with their causes and pathophysiologic
mechanisms.

See rsna.org/learning-center-rg.

Dysphagia is a common symptom in the general population, and its
prevalence increases with patient age. The deterioration of swallow­
ing function has many acute and chronic causes, including cerebro­
vascular and neuromuscular diseases, radiation, and surgery. In an
elderly population, diagnosis and treatment of swallowing abnor­
malities is a high priority because it improves the patient’s quality
of life and helps them to avoid medical complications. Fluoroscopic
swallowing examinations and modified barium swallow studies are
the most used and most reliable diagnostic procedures to evaluate
swallowing disorders. Functional anomalies include disturbances
of the oral preparatory, oral propulsory, and pharyngeal phases
of swallowing as premature spillage from the mouth, nasal regur­
gitation, delayed initiation of pharyngeal swallowing, incomplete
displacement of the hyolaryngeal complex, abnormal epiglottic
tilt, incomplete laryngeal closure, and pharyngeal dysmotilities.
Anatomic abnormalities of the pharynx include diverticula, be­
nign strictures, and tumors. The abnormalities diagnosed on the
basis of fluoroscopic examination have a variety of treatment strat­
egies, and the choice of treatment depends on the cause of the
anomaly and its pathophysiologic characteristics. The radiologist’s
interpretation of these characteristics is crucial to therapeutic de­
cision making and achieving the best patient outcomes.

Online supplemental material is available for this article.

©RSNA, 2021 • radiographics.rsna.org

Introduction
Oropharyngeal dysphagia is prevalent in 20% of the general popu­
lation and in 50% of nursing home residents in the United States
(1). As the average age of the population continues to increase,
there has been an increase in dysphagia and related complications.
Fluoroscopically guided swallowing examinations are the most used
technique for evaluation of deglutition disorders. The examination is
called modified barium swallow when the diagnostic study includes a
therapeutic test; in those cases, it is performed with the participation
of a swallowing therapist or speech­language pathologist (2).

Fluoroscopic examination of swallowing and modified barium
swallow should not be routine studies but should be custom­tailored
techniques designed by radiologists and swallowing therapists on
the basis of the patient’s clinical history and symptoms. Radiolo­
gists should supervise or participate in the procedures and contrib­
ute their knowledge to adapt the technique to unexpected findings
detected during examinations. They may decide during the study
to include the evaluation of organs such as the esophagus that may
explain or be associated with the patient’s symptoms. The radiologic

GASTROINTESTINAL IMAGING

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TEACHING POINTS
	„ Fluoroscopic examination of swallowing and modified barium
swallow should not be routine studies but should be custom-
tailored techniques designed by radiologists and swallowing
therapists  on  the  basis  of  the  patient’s  clinical  history  and
symptoms. Radiologists should supervise or participate in the
procedures and contribute their knowledge to adapt the tech-
nique to unexpected findings detected during examinations.
They may decide during the study to include the evaluation of
organs such as the esophagus that may explain or be associ-
ated with the patient’s symptoms.

	„ For evaluation of the function of the PES, radiologists should
correlate the following functional units: (a) the opening of the
PES, (b) the elevation of the HLC, and (c) the pharyngeal con-
traction.  Understanding  the  different  possible  mechanisms
that cause the abnormal function of the segment is essential
in deciding the best treatment strategies.

	„ As part of the fluoroscopic swallowing examination, a system-
atic evaluation of the air-filled structures and soft tissues of the
neck may provide information about the causative or associ-
ated abnormalities relating to the patient’s symptoms.

	„ The development of Zenker diverticula may involve anatomic
and  pathophysiologic  causes  that  include  an  area  of  wall
weakness, a distal obstruction due to the diminished opening
of the CP, and increased pharyngeal intraluminal pressure as a
consequence of mechanical obstruction of the outlet.

	„ The radiologic report should include all detected abnormali-
ties and should not be limited to description of the visualiza-
tion of penetration or aspiration. Because each abnormality
has  its  own  specific  therapeutic  approach,  the  description
of  radiologic  findings  and  their  correlation  with  the  patho-
physiologic mechanisms and possible causes should be stated
clearly in the report. A meticulous radiologic diagnosis facili-
tates the decision making of referring physicians and swallow-
ing therapists.

report should describe all the findings additional
to penetration or aspiration and present the facts
in a way that facilitates decision making by the
referring physicians and swallowing therapists.

This article reviews the anatomy and physiol­

ogy of swallowing, explains the indications for
and techniques of fluoroscopic examination,
describes abnormal radiologic findings, and dis­
cusses their pathophysiologic mechanisms.

The discussion includes the abnormalities
of the pharyngoesophageal segment (PES) as
diminished or delayed opening and early clos­
ing and the pathophysiology of the pharyngeal
residue after swallowing, penetration, and
aspiration. Complications of total laryngectomy
are examined, such as leakage, pseudoepiglot­
tis, anterior pharyngeal pouches, neopharyngeal
dysmotilities, strictures, and malfunctioning
of the tracheoesophageal prosthesis for voice
reconstitution. We describe the radiologic find­
ings of each abnormality and provide sample
images and a discussion of the possible mecha­
nisms, with consideration of the patient’s clinical
history.

Anatomy for Radiographic
Interpretation

The oral cavity is bounded by the hard and soft
palates superiorly, by the tongue inferiorly, and
opens to the oropharynx posteriorly. The nasophar-
ynx or epipharynx is bounded by the pharyngeal
walls posteriorly and laterally, by the skull base su­
periorly, and by the soft palate inferiorly. It opens
to the nasal cavity anteriorly and communicates
with the oropharynx inferiorly through the palato­
pharyngeal isthmus or velopharyngeal seal.

The oropharynx or mesopharynx is bounded
posteriorly and laterally by the pharyngeal walls
and constrictor muscles and inferiorly by the su­
perior surface of the epiglottis and the hyoid bone.
It communicates with the nasopharynx superiorly
and with the mouth anteriorly. The laryngophar-
ynx or hypopharynx is bounded by the pharyngeal
walls posteriorly and laterally and extends to the
lower border of the cricoid cartilage inferiorly. It
communicates with the oropharynx superiorly,
with the cervical esophagus inferiorly, and with the
laryngeal vestibule anteriorly (3–6) (Fig 1).

Phases of Swallowing

Oral Preparatory Phase
The oral preparatory phase involves chewing the
food and mixing it with saliva. When the bolus
is considered “swallowable,” it is placed between
the upper surface of the tongue blade and the
palate. The tip of the bolus is held by a seal
formed by the tongue and the soft palate that
prevents premature leakage into the pharynx
before swallowing (7,8) (Fig 2A).

Oral Propulsory Phase
During the oral propulsory phase, the bolus is pro­
pelled into the oropharynx by means of an up­
ward and backward movement of tongue. During
the passage of the bolus, the soft palate elevates
to a right angle to oppose the contraction of the
posterior and lateral pharyngeal walls that form
the Passavant ridge to close the palatopharyngeal
isthmus and prevent the penetration of material
into the nasopharynx (Fig 2B).

Initiation of Pharyngeal Swallow
The next phase is the initiation of the pharyngeal
swallow, when the bolus passes the pharyngeal
pillars and enters into the oropharynx, triggering
the reflex that initiates the nonvoluntary pharyn­
geal phase of swallowing.

Pharyngeal Phase
In the pharyngeal phase, the hyolaryngeal complex
(HLC) elevates and shortens the pharynx, de­
flects the epiglottis, closes the larynx, and opens

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Carbo et al  1735

the PES (Fig 2C). Laryngeal closure starts in the
true vocal folds, followed by the false vocal folds,
and ends in the laryngeal vestibule. Concurrently,
the stripping contraction wave of the posterior
and lateral pharyngeal walls begins and propels
the bolus into the esophagus.

PES Opening Phase
The PES opening phase consists of (a) relaxation of
the upper esophageal sphincter (UES); (b) upward
and anterior traction of the cricoid cartilage, which
is attached to the HLC; and (c) opening of the
lumen by means of increased intrabolus pressure
by the thrust of the dorsum of the tongue and the
pharyngeal constrictors (Fig 2D) (9).

Esophageal Phase
The esophageal phase begins when the bolus is
propelled through the esophagus into the stom­
ach by means of esophageal peristalsis. Once
the bolus passes into the esophagus, (a) the
palatopharyngeal isthmus opens, reestablishing
the communication between the nasopharynx
and oropharynx and allowing the passage of air;
(b) the HLC returns to resting position; (c) the
larynx opens; (d) the epiglottis returns to upright
position; (e) the PES closes, and (f) respiration
resumes (Fig 2E).

Indications for Fluoroscopic
Swallowing Examinations
Common indications for fluoroscopically guided
swallowing examinations are oropharyngeal
dysphagia (swallowing difficulty); globus sensa­
tion; choking and coughing during swallowing;
prolonged intubation; cerebrovascular events (ie,
stroke); and surgery, trauma, or radiation treat­
ments to the head and neck (10).

Figure  1.
Illustration
shows the anatomy of
the pharynx.

Fluoroscopic Swallowing Examination
Technique
The equipment used includes a radiologic appa­
ratus with fluoroscopy and video recording with
slow motion, reverse, and stop­frame capabili­
ties (2,10–13). The patient should be upright
or seated in a comfortable position, with their
dentures in their mouth.

Lateral views are the most useful to evaluate
all phases of swallowing and to detect penetra­
tions into the airway. Oblique views are per­
formed to visualize the PES without the shoulder
in the way. Frontal views are used to diagnose
asymmetric swallowing abnormalities.

Use of short exposure times and high kilovolt­
age is recommended to improve image resolution
and minimize motion blurring of the bolus and
anatomic structures. For a functional examina­
tion, the contrast material used is barium sulfate
in a concentration of 40% to 60% weight/volume
(mass of solute/volume of solution). Multiple
barium viscosities such as thin liquid, nectar
thick, honey thick, paste, and solids are used at
the speech­language pathologist’s discretion.
Iodinated water­soluble contrast material is used
when leakages or perforations are suspected (13).
Videofluoroscopic recording is used to detect

functional abnormalities at 30 frames per sec­
ond. Compared with videofluoroscopic record­
ing, rapid­sequence digital images are acquired
at fewer frames per second, but the images have
better spatial resolution and are preferred for
anatomic details.

The personnel included in a modified barium
swallow examination are a radiographic technolo­
gist, a radiologist, and a speech­language patholo­
gist. The role of the speech­language pathologist
is to use strategies that may improve the efficiency

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Figure  2.
Illustrations  show  the
phases of swallowing, which include
the  oral  preparatory  phase  (A),
the oral propulsory phase (B), the
pharyngeal  phase  (C),  the  PES
phase  (D),  and  the  esophageal
phase (E).

and safety of swallowing, to educate patients about
their swallowing function, and to provide swallow­
ing recommendations on the basis of the radio­
graphic findings after study completion.

Evaluation of esophageal anatomy and motility

is important. The anatomic site that the patient
identifies as the source of the symptoms is not
a reliable indicator of the location of the cause.
Thus, radiologic examinations of patients with
dysphagia should include a morphologic and func­
tional evaluation of the esophagus and esophago­
gastric junction, which may be performed before
or after the swallowing examination.

Functional Abnormalities

Abnormalities of Oral Preparatory Phase
The motion of the tongue is essential for bolus
manipulation and the functions of chewing, mix­
ing food with saliva, and holding the bolus in the
mouth before swallowing. When the tongue is

dysfunctional, images may show uncoordinated
movements, fragmentation of the bolus, inability
to hold it, and drooling and leaking of contrast
material into the sulci of the cheeks and floor of
the mouth (Fig 3). Causes of tongue failure can
be secondary to atrophy, xerostomia, surgery, or
severe nerve or brain injuries (7,14,15).

Premature Spillage from Mouth into
Pharynx
The back of the tongue blade and the soft pal­
ate form the glossopalatal seal, which keeps the
bolus in the mouth before swallowing. Premature
spillage from the mouth into the pharynx may be
caused by unilateral or bilateral incompetence of
the seal, which may allow leakage of material into
the pharynx before a swallowing attempt, leading
to aspiration through an opened and unprotected
airway (Fig 4). Seal ineffectiveness can be a result
of weakness, atrophy, or poor muscular coordina­
tion of the tongue and soft palate due to aging,

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Carbo et al  1737

Figure 3.  Leakage into the floor of the mouth in a 77-year-old
woman. Lateral radiograph of the oral cavity after the swallow
shows that contrast material has leaked into the mouth floor
(large arrow) and the sulci of the cheeks (small arrows) because
of incompetence of the tongue.

Figure  4.  Leakage  from  the  mouth  into  the  pharynx  in  a
58-year-old woman. Lateral radiograph of the oral cavity and
pharynx  before  swallowing  shows  contrast  material  leaking
from the mouth bolus to the valleculae and hypopharynx (ar-
rows) due to incompetence of the glossopalatal seal.

surgery, radiation, or acute and chronic neuro­
logic illnesses. For example, patients with Parkin­
son disease may perform repetitive unsuccessful
attempts to swallow the bolus (10,14).

Delayed Initiation of Pharyngeal Swallow
When the bolus reaches the oropharynx, it
triggers the swallowing reflex that initiates the
nonvoluntary pharyngeal phase of swallowing.
The initiation of the pharyngeal swallow is rec­
ognized radiographically by the elevation of the
hyoid bone as a component of the HLC. Hyoid
elevation starts when the tip of the bolus crosses
the angle of the mandible. A delayed swallowing
initiation is identified when the contrast material
is seen in the pharyngeal lumen but the hyoid
bone remains in a resting position (Fig 5). Causes
include decreased pharyngeal sensory perception
due to injury of mucosal receptors or neurologic
damage secondary to aging, radiation, a cerebro­
vascular accident, or surgery (7,14).

Nasal Regurgitation
The palatopharyngeal isthmus or seal should be
closed during the bolus transportation from the
mouth into the oropharynx. Nasal regurgitation
is diagnosed radiographically by evaluating pas­
sage of the contrast material through a nonclosed
seal into the nasopharynx (Fig 6). Nasal penetra­
tion can occur during transfer of the bolus from
the mouth to the pharynx due to incompetence
of the isthmus or after swallowing when the
seal is open and there is regurgitation from the
distal pharynx or esophagus due to an associated
distal dysfunction or mechanical obstruction.
The causes of an incompetent seal and nasal

Figure  5.  Delayed  initiation  of  the  pharyngeal  swal-
low in a 55-year-old man. Lateral radiograph shows the
bolus in the oropharynx and hypopharynx (*), with the
hyoid bone still in resting position (arrow) due to a de-
layed triggering of the swallowing reflex.

radiation, surgery, or a cerebrovascular accident.
Atrophy of the tongue or soft palate can lead
to compensatory hypertrophy of the opposite
muscle (10,14).

Delayed or Slow Oral Propulsory Phase
When the bolus is judged to be “swallowable,”
it is placed in a midline depression in the upper
surface of the tongue blade until it is transferred
into the pharynx. A delayed initiation of tongue
propulsion or a slow transportation of the bolus
to the pharynx can be secondary to weakness or
the inability of the tongue to function because of

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Figure  8.  Frozen  pharynx  in  a
68-year-old  woman  with  a  his-
tory  of  radiation  therapy.  Lateral
radiograph shows absent contrac-
tions and rigidity of the pharyngeal
walls  during  the  passage  of  bolus
and penetration of contrast mate-
rial into the larynx (arrow).

Figure 6.  Nasal regurgita-
tion  in  a  62-year-old  man.
Lateral  radiograph  shows
contrast  material  penetrat-
ing  into  the  nasopharynx
from  the  oropharynx  (*)
during  bolus  displacement
because  of  insufficient  clo-
sure  of  the  palatopharyn-
geal isthmus.

Figure  7.  Limited  elevation  of
the  hyolaryngeal  complex  in  a
74-year-old  man.  Lateral  radio-
graph  during  swallowing  shows
that  the  hyoid  bone  (blue  arrow)
did  not  reach  the  mandible  at  its
maximum displaced position, as is
expected  in  healthy  patients.  The
limited  displacement  may  be  due
to  scarring  of  pharyngeal  elevator
muscles from radiation treatment.
Associated  findings  are  a  poor
pharyngeal contraction, an incom-
plete  closure  of  the  larynx  with
contrast  material  penetration  (red
arrow), and a diminished opening
of the PES (yellow arrow).

regurgitation include atrophy and insufficient
elevation of the soft palate due to neurologic
diseases, radiation, surgery, or congenital issues
such as a cleft palate or a fistula (7,14,16). An
oronasal fistula must be ruled out during the
examination.

Slow or Incomplete Displacement
of HLC
A full upward and forward displacement of the
HLC is necessary to elevate and shorten the
pharynx, deflect the epiglottis, close the larynx,
and open the PES. The HLC is fully elevated
when the hyoid bone is seen at the level of the
inferior margin of the mandible. Slow or incom­
plete elevation of the HLC is due to weakness of
the suprahyoid muscles and pharyngeal elevators
(Fig 7). Muscular weakness is a consequence of
atrophy and fibrosis secondary to aging, radia­
tion, and neurologic or cerebrovascular diseases
(14).

Weakness of Tongue and Pharyngeal
Contraction
Adequate thrust of the dorsum of the tongue
and the pharyngeal walls is required to increase
intrabolus pressure and propel the bolus into the

Figure  9.  Hypotony  of  the  left
pharyngeal  wall  in  a  59-year-old
woman. Frontal radiograph of the
pharynx during swallowing shows
bulging of the left pharyngeal wall
(arrowhead)  and  an  asymmetric
tilt  of  the  epiglottis  (arrow).  Find-
ings  were  due  to  a  nerve  injury
during  surgery  for  resection  of  a
tumor in the base of the skull.

esophagus. Unilateral or bilateral weakness or
atrophy of the muscles may prevent a timely and
complete bolus displacement. In severe cases
of atony, as with a “frozen pharynx,” the bolus
mostly moves by means of gravity (Fig 8). Lack
of appropriate contraction leaves residue in the
pharynx after swallowing and increases the risk
of aspiration. Reduced pharyngeal contraction
may be caused by muscular or neurologic dam­
age due to radiation, surgery, or neurovascular
diseases. Weakness can be bilateral or unilateral
(Fig 9) (7,10,14,15).

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Carbo et al  1739

push the bolus and a distal relaxation to al­
low its passage. At fluoroscopy, abnormalities
of pharyngeal peristalsis are recognized by
the presence of nonpropulsive contractions
that interrupt bolus passage and fragment the
contrast material in the pharyngeal lumen (Fig
10). Residue left in the pharyngeal lumen after
swallowing can lead to aspiration. The paralysis
can be bilateral because of injury of the pharyn­
geal innervation that is secondary to radiation,
inflammatory changes, or neurologic diseases
or unilateral because of peripheral nerve injury
during surgery (7,14).

Limited Tilt of Epiglottis
During swallowing, the tilt of the epiglottis pro­
tects the entrance of the laryngeal vestibule and
deflects the bolus into the lateral food pathways
(pyriform sinuses). As a consequence, an insuf­
ficient or absent epiglottic tilt may obstruct the
passage of the bolus and risk penetration of
material into the laryngeal inlet during swallow­
ing (Fig 11). Causes of inadequate epiglottic tilt
include insufficient displacement of the HLC,
pharyngeal or laryngeal tumors, or fibrosis due to
radiation (7,14).

Delayed or Incomplete Laryngeal Closure
Laryngeal closure starts with and continues as
HLC displacement. It starts in an inferior to
superior direction, beginning in the true vocal
folds, followed by the false vocal folds, and end­
ing in the laryngeal vestibule to expel penetrated
material back into the hypopharynx. Closure of
the laryngeal vestibule is recognized at fluoros­
copy as the narrowing and disappearance of the
air column in the laryngeal lumen during the
HLC elevation. A delayed, slow, or incomplete
closure of the larynx during swallowing may lead
to aspiration (Fig 12). Failure of laryngeal closure
may result from insufficient HLC elevation, cer­
vical surgery, laryngeal fibrosis due to radiation,
or weakness of the supraglottic adductors due to
edema or fibrosis (14,17).

Incomplete Opening of PES
The UES is a high­pressure zone at the PES that
is formed by muscular fibers of the thyropharyn­
geus, cricopharyngeus (CP), and circular fibers
of the proximal esophagus. The PES is normally
closed to prevent inhaled air from passing into the
esophagus and gastroesophageal reflux from enter­
ing into the airway. It opens during swallowing to
allow passage of the bolus, vomiting, or eructation.
Opening the PES involves (a) neural relaxation of
the tonically contracted UES muscles, (b) normal
distensibility of the segment, (c) traction forces
imparted by the opening of the UES muscles, and

Figure  10.  Nonpropulsive  pharyngeal  contrac-
tions in a 66-year-old man. Lateral radiograph of
the pharynx during swallowing shows narrowing
of the pharyngeal lumen (arrowheads) when the
hyoid bone is still elevated (blue arrow). Because
of  premature  pharyngeal  closure,  some  contrast
material  was  trapped  in  the  oropharynx  (*)  and
penetrated the laryngeal vestibule (red arrow).

Incomplete  epi-
Figure  11.
glottis tilt in a 72-year-old man.
Lateral  radiograph  shows  a
swelling  epiglottis  in  upward
position  during  the  bolus  pas-
sage (arrow). As a consequence
of the insufficient tilt of the epi-
glottis,  a  partial  obstruction  of
bolus  displacement  and  pen-
etration  of  contrast  material
into the laryngeal vestibule (*)
are visible.

Figure 12.
Insufficient closure
of  the  laryngeal  lumen  during
swallowing  in  a  69-year-old
woman.  Lateral  radiograph  of
the  pharynx  during  swallow-
ing shows an opened laryngeal
vestibule  with  penetration  of
contrast  material.  Additional
findings  are  deformity  of  the
epiglottis  (*),  poor  pharyngeal
contractions, and a stricture of
the PES (arrow) due to chemo-
therapy and radiation therapy.

Lack of Synchronization of Pharyngeal
Contractions
Peristalsis is a wave­like involuntary contraction
of the gastrointestinal tract with the purpose
of transporting the bolus. It consists of strip­
ping contractions of the proximal muscles to

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Diagnosis and Treatment of Pharyngoesophageal Segment Dysmotilities

PES Dysmotility

PES Opening

Mechanism

Therapeutic Objective

Maneuvers

Delayed PES opening due
to slow HLC displace­
ment

Full opening only

when the HLC is
completely elevated

Delayed PES opening

Full opening only

Delayed initiation
of pharyngeal
swallow
UES spasm

when UES is relaxed

Improve speed of swal­
lowing initiation

Bolus stimulation

Abbreviate the UES

Increase bolus vol­

relaxation

ume and thickness

due to impaired UES
relaxation

Incomplete PES opening
due to nonrelaxation of
CP (CP achalasia)

Incomplete PES opening
due to lack of elasticity
of the CP (fibrosis)
Incomplete PES opening
due to partial displace­
ment of HLC

Incomplete PES opening
due to weak pharyngeal
contraction

Early PES closure due to
premature HLC return

Early PES closure due
to premature UES
contraction

Incomplete

CP nonrelaxation

Improve CP relaxation Endoscopic dilation
Botulinum toxin A

Incomplete

CP lack of elastic­
ity (fibrosis)

PES dilation

Incomplete

Weakness of HLC

Strengthening of HLC

elevators

elevators

Incomplete

Weak pharyngeal
muscular con­
tractions

Improvement of pha­
ryngeal contraction

Full opening only

Weakness of HLC

Increase and extend the

when the HLC is
completely elevated

elevators

HLC elevation

Full opening only

UES spasm

Delay the UES con­

when the UES is
relaxed

traction

injection
CP myotomy
Effortful swallow
Endoscopic dilation
CP myotomy
Mendelsohn
Effortful swallow
Shaker
Base of tongue exer­

cises

Tongue hold
Mendelsohn
Increase bolus vol­

ume and thickness;
Mendelsohn
Increase bolus vol­

ume and thickness

PES dilation

Sources.— References 9,10,14,18–26.

(d) intrabolus pressure generated by contraction
of the pharynx.

Primary causes of incomplete opening of the
UES during the passage of the bolus are (a) in­
complete relaxation of the UES (achalasia) or lack
of coordination with the pharyngeal contraction
(dyskinesia), (b) abnormal elasticity and dis­
tensibility of the CP as result of degeneration of
muscle fibers and replacement with fibroadipose
tissue, (c) noncomplete displacement of the HLC
during swallowing, and (d) insufficient intrabolus
pressure to open the lumen due to impairment of
the tongue and pharyngeal constrictor muscles
(Table) (7,9,14,18–26). Narrowing of the PES
prevents the free and complete passage of the
bolus into the esophagus, resulting in incomplete
clearance and residue in the pyriform sinuses,
with potentially postdeglutitive aspiration.

On a lateral view, the diminished opening of the

PES is recognized by a posterior protrusion (CP
bar) between C3 and C6 during the trans­sphinc­
teric passage of the bolus (Fig 13). For evaluation
of the function of the PES, radiologists should
correlate the following functional units: (a) the
opening of the PES, (b) the elevation of the HLC,
and (c) the pharyngeal contraction. Understand­
ing the different possible mechanisms that cause

the abnormal function of the segment is essential
in deciding the best treatment strategies.

Delayed Opening of PES
During swallowing, the PES opens completely
upon the arrival of the bolus to allow it to pass
into the esophagus. Delayed opening of the PES
is a consequence of delayed elevation of the HLC
or retarded relaxation of the UES (Table). When
the delayed opening is due to slow or retarded
relaxation of the UES, the hyoid bone is already
elevated when the PES is still closed (Fig 14).
Because the PES remains closed on the arrival of
the bolus, there is a transient luminal obstruction
that augments the pressure and distends the lu­
men of the proximal pharynx, increasing the risk
of aspiration (9,14).

Early Closure of PES
The PES should only close after the bolus has
passed completely into the esophagus. A prema­
ture closure of the PES can be due to an early
contraction of the UES before the HLC returns
to resting position and the bolus pass is finished
(Fig 15) or a premature return of the HLC to
resting position (Fig 16) (Table). An early closure
of the PES can block the bolus and leave residue

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Carbo et al  1741

Figure  13.  Diminished  opening  of  the  PES  in
a 44-year-old woman with gastroesophageal re-
flux.  Lateral  radiograph  of  swallowing  shows  a
transverse  filling  defect  in  the  posterior  wall  of
the PES, called the CP bar (yellow arrow), when
the hyolaryngeal complex is fully elevated (blue
arrow). The luminal narrowing obstructs the pas-
sage of the bolus and distends the proximal pha-
ryngeal lumen.

Figure  14.  Delayed  opening
of  the  PES  due  to  retarded  relax-
ation  of  the  UES  in  a  71-year-old
woman. Lateral radiograph shows
the bolus tip at the PES entrance,
which  remains  closed  (yellow  ar-
row),  even  when  the  hyoid  bone
is  fully  elevated  (blue  arrow).  On
subsequent  images  (not  shown),
the PES opened completely, allow-
ing the full passage of the bolus.

Figure 15.  Early closure of the PES due to
premature closing of the UES in a 62-year-
old  man.  (A)  Lateral  radiograph  shows  a
normal PES opening during the passage of
the  bolus.  (B)  Delayed  lateral  radiograph
shows an early closing of the PES (arrow-
heads),  while  the  hyoid  bone  is  still  ele-
vated (arrow in A and B). The early closure
of  the  PES  interrupts  the  passage  of  the
bolus, leaving residue in the hypopharynx
(*), with increased risk of aspiration.

in the pyriform sinuses after swallowing, leading
to aspiration when the airway reopens (9,14).

Residue in Valleculae and Pyriform
Sinuses after Swallowing
After swallowing, no materials or contrast ma­
terial should remain in the pharyngeal lumen.
Residue in the vallecullae, pyriform sinuses,
or pharyngeal walls may lead to postswallow­
ing aspiration when respiration is resumed (Fig
17A–17C). After swallowing, pooling of contrast
material in the valleculae can result from impaired
backward movement of the dorsum of the tongue
or insufficient epiglottic tilt. Residue in the pyri­
form sinuses may result from impaired pharyngeal
contraction, PES dysmotilities, or mechanical
obstruction. Unilateral pooling can be secondary
to paralysis of the lateral pharyngeal wall due to a
nerve or muscle injury (Fig 17D) (14).

Penetration.—No contrast material should
penetrate the laryngeal vestibule before, during,
or after swallowing. Penetration is diagnosed at
fluoroscopy when contrast material is seen in the
laryngeal lumen. During swallowing, penetrated
material should be extruded back into the phar­
ynx by laryngeal contraction (ie, flash penetration).
In severe cases, contrast material may remain
in the laryngeal vestibule, reach the vocal folds,
and pass into the trachea. Whenever possible, the
mechanism responsible for penetration should be
recognized during the examination and stated in
the report to allow decision making on the best
therapeutic approach. Preswallowing penetrations
are usually a consequence of delayed initiation
of the swallowing reflex. Penetrations during
swallowing can be due to one or multiple abnor­
malities such as incomplete or slow elevation of
the HLC, epiglottis tilt, incomplete closure of the

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Figure 16.  Early closure of the PES due to premature
return  of  the  hyolaryngeal  complex  in  a  55-year-old
woman.  (A)  Lateral  radiograph  shows  normal  open-
ing of the PES during swallowing, with the hyoid bone
fully  elevated  (blue  arrow).  An  incidental  finding  is  a
penetration  during  swallowing  (red  arrow).  (B)  De-
layed  lateral  radiograph  of  the  same  swallow  shows
an early closure of the PES (arrowhead) due to a pre-
mature return of the HLC, which is evidenced by the
low position of the hyoid bone (blue arrow). The early
closure  of  the  PES  interrupted  the  complete  passage
of the bolus and left residue in the hypopharynx (*).

Figure 17.  Residue in the valleculae and pyriform sinuses after swallowing. (A) Lateral radiograph of the pharynx in a 72-year-
old man after swallowing shows contrast material pooling in the valleculae (V) and pyriform sinuses (PS). (B) Frontal radiograph
in a 40-year-old man after spinal fixation shows bilateral residue in the valleculae (green arrows) and pyriform sinuses (red arrows).
(C) Lateral radiograph in a 67-year-old woman after swallowing shows the penetration of residual contrast material (arrowhead) into
the larynx from the pyriform sinuses (*). (D) Frontal radiograph in a 72-year-old man after right-sided skull base surgery shows residue
in the right pyriform sinus (arrow) due to unilateral deficiency of the pharyngeal contraction.

laryngeal vestibule, or motility disorders of the
pharynx or PES. Pharyngeal residue is respon­
sible for penetrations after swallowing (14).

Aspiration.—Aspiration is diagnosed when con­
trast material is seen in the tracheal lumen, below
the vocal cords (Fig 18). Aspiration is a more
severe complication than penetration and may be
minimal, moderate, or massive when the con­
trast material reaches the carina and bronchus.
Aspirated materials in the trachea may generate
a protective cough to expel them back into the
pharynx or may be nonsensate (ie, silent). A de­
layed or absent cough reflex is valuable informa­
tion by which to estimate severity, because silent
aspirators have a greater risk of developing pneu­
monia. In addition to the causes of penetration,
a delayed or insufficient closure of the vocal folds
due to edema, radiation fibrosis, or surgery of the
vocal cord adductors may contribute to aspira­
tion. External­beam radiation treatment for neck

cancer is a frequent cause of aspiration because it
may impair all phases of swallowing.

Anatomic Abnormalities

Radiography of the Neck
As part of the fluoroscopic swallowing exami­
nation, a systematic evaluation of the air­filled
structures and soft tissues of the neck may
provide information about the causative or as­
sociated abnormalities relating to the patient’s
symptoms. The patient should be evaluated for
(a) soft palate atrophy due to radiation or sur­
gery or compensatory hypertrophy due to tongue
atrophy (Fig E1); (b) tongue atrophy due to
aging, radiation, or surgery (Fig E2); (c) epiglot­
tis enlargement due to acute radiation (Fig E3),
infection, and tumors or atrophy due to radia­
tion; (d) swelling of prevertebral soft tissues due
to chemotherapy, radiation, or surgery (Fig E4)
and tumors, abscesses, or hematomas; (e) air

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Carbo et al  1743

Figure  18.  Aspiration  in  a  77-year-old  man.
Lateral  view  of  swallowing  shows  contrast  ma-
terial penetration into the laryngeal vestibule (*)
and  aspiration  into  the  tracheal  lumen  (red  ar-
row) through the vocal folds (white arrows).

Figure  19.  Web  in  a  66-year-old
woman.  Lateral  radiograph  of  the
pharynx during swallowing shows a
thin horizontal linear filling defect in
the anterior wall of the hypopharynx
that obstructs the lumen (arrow).

Figure  21.  Pharyngeal  tumor  in
a  78-year-old  man.  Swallowing  ex-
amination  shows  an  irregular  lumi-
nal  narrowing  of  the  pharynx,  with
posterior displacement due to a large
infiltrating mass (arrows).

Figure  20.  Radiation  stricture  in
a  77-year-old  man.  Lateral  radio-
graph of swallowing shows a short
severe luminal stricture in the phar-
ynx due to scarring (arrow), with a
mild proximal luminal distention.

in the prevertebral soft tissues due to trauma
(Fig E5), gastrointestinal perforations (Fig E6),
diverticula (Fig E7), or in other locations as
postsurgical leakage (Fig E8); (f) soft­tissue­
attenuation obstructive masses in the lumen of
pharynx (Fig E9), larynx (Fig E10), or PES (Fig
E11); (g) pharyngeal deformities as a nonclosed
PES at rest due to fibrosis because of radiation
therapy (Fig E12) or esophageal dilations due to
achalasia (Fig E13) or scleroderma; (h) abnor­
mal soft­tissue calcifications; and (i) bone and
postsurgical abnormalities.

Pharyngeal Strictures
Webs are thin mucosal folds that are frequently
seen in the anterior wall or circumference of the
hypopharynx or proximal esophagus. Webs are
associated with gastroesophageal reflux and syn­
dromes such as Plummer­Vinson or epidermolysis
ampullosa and are seen as 2–4­mm­thick trans­
verse linear filling defects in the hypopharynx and
cervical esophagus that may partially obstruct the
lumen and passage of the bolus (Fig 19) (27).

Radiation strictures are a delayed complication

of radiation due to vascular damage, ischemia,
and collagen deposition, with subsequent fibrosis
and scarring (Fig 20) (27,28).

Cervical esophageal tumors can be seen radio­
graphically as irregular or lobulated filling defects
protruding into the lumen of the pharynx or
larynx on radiographs or swallowing examina­
tions (Fig 21) (27). Cervical tumors are more ac­
curately detected and staged with cross­sectional
imaging such as CT, MRI, or PET.

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Figure  22.  Zenker  diverticulum  in  two  patients.  (A)  Illustration  shows  a  diverticulum  (green  arrow)
emerging from a triangular-shaped area in the posterior wall of the hypopharynx (blue and yellow ar-
rows), which was formed superiorly by the oblique fibers of the thyropharyngeus and inferiorly by hori-
zontal fibers of the cricopharyngeus. (B) Lateral radiograph during swallowing in a 74-year-old woman
shows  a  diverticulum  in  the  posterior  wall  of  the  hypopharynx  (red-orange  arrow)  above  the  CP  bar
(yellow arrow). (C) Frontal radiograph in a 79-year-old man after swallowing contrast material shows
the diverticulum mildly displaced to the left side of the patient (*) and residue in both pyriform sinuses
(arrows).

Zenker Diverticula
Zenker diverticula are outpouchings lined by squa­
mous epithelial mucosa and submucosa and are
often surrounded by fibrous tissue, with absent
muscular fibers. They are located in an area of
muscular weakness called the Killian dehiscence
or the triangle of Laennec in the posterior wall of
the hypopharynx and are limited by the oblique
fibers of the thyropharyngeous superiorly and
laterally and by the horizontal fibers of the CP
inferiorly (Fig 22A).

The development of Zenker diverticula may
involve anatomic and pathophysiologic causes that
include an area of wall weakness, a distal obstruc­
tion due to the diminished opening of the CP,
and increased pharyngeal intraluminal pressure as
a consequence of mechanical obstruction of the
outlet. Strong evidence now shows that acquired
Zenker diverticula are, in most cases, second­
ary to a poorly compliant but normally relax­
ing CP muscle that cannot fully distend during
the process of sphincter opening. The increased
resistance to flow during swallowing in an attempt
to overcome the distal obstruction markedly in­
creases the forces required to drive the passage of
the bolus. Increased intrabolus pressure imparted
to the area of relative muscular weakness (Killian
dehiscence) over many years gives rise to a poste­
rior herniation of the pouch (27,29,30).

Fluoroscopically, the diverticulum is seen
during and after swallowing as an outpouching

arising from the posterior hypopharyngeal wall
above the prominence of the CP bar (Fig 22B).
In frontal views, a small diverticulum is seen in
the midline, but when it becomes larger, it may
relocate laterally, more frequently to the left side
(Fig 22C). After swallowing, the content of the
diverticulum may empty back into the hypo­
pharynx, increasing the risk of postswallowing
aspiration.

Pseudo-Zenker diverticula are saclike collections
of contrast material that are trapped in the same
location as that of the Zenker diverticula (27).
They are seen only after swallowing when the
pharyngeal lumen is collapsed and not when the
lumen is fully distended (Fig 23).

Killian-Jamieson Diverticula
Killian-Jamieson diverticula are outpouchings from
the anterior lateral wall of the cervical esophagus
through a gap between the inferior margin of the
cricoid cartilage and CP and the lateral wall of
the suspensory ligament of the esophagus (Fig
24A) (27). They are seen during swallowing stud­
ies as lateral or anterior outpouchings below the
level of the CP (Fig 24B).

Complications of Total Laryngectomy

Surgical Technique
Total laryngectomy is indicated for advanced or
nonradiosensitive laryngeal or cervical tumors.

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Carbo et al  1745

Figure  23.  Pseudo-Zenker  diverticulum  in  a
69-year-old  woman.  Lateral  radiograph  of  the
pharynx after swallowing shows an outpouching
in the location of the Zenker diverticula (arrow).
The  outpouching  was  not  identified  when  the
pharyngeal lumen was fully distended during the
passage of the bolus (not shown).

Figure  24.  Killian-Jamieson  diverticulum  in  a  72-year-old
man. (A) Illustration shows a diverticulum emerging from the
anterolateral wall of the cervical esophagus (arrow) below the
CP muscle. (B) Frontal radiograph during swallowing shows a
right lateral diverticulum (arrow).

The surgical technique consists of removal of the
hyoid bone, thyroid and cricoid cartilages, epiglot­
tis, and vocal folds (Fig 25A), followed by recon­
struction and closure of the anterior defect with
mucosa, pharyngeal muscles, and skin (Fig 25B).
Finally, optional vocal restoration can be achieved
through creation of a fistula between the trache­
ostoma and the esophagus, with placement of a
silastic prosthesis of varying length and diameter
in the fistula to allow the one­way passage of air
for speech rehabilitation (Fig 25C). In patients
with the tracheoesophageal fistula, the evaluation
of prosthesis position and function and PES motil­
ity during phonation should be included as part of
the swallowing evaluation (31–33).

Anastomotic Leakage
Anastomotic leakage is a frequent complication
in the early postoperative period. Risk factors
include oral infection, salvage total laryngec­
tomy, and prior radiation therapy. Leakages are
detected at a swallowing examination as blind
outpouchings outside the neopharyngeal lumen
(sinus tracts) or as an extraluminal tract of con­
trast material that communicates with the skin
(Fig 26) (27,34,35).

Pseudoepiglottis
A pseudoepiglottis is an enlargement of the folds at
the base of the tongue due to the pull of pharyn­
geal constrictors when a patient attempts to swal­
low. The abnormality is seen as an anterior linear
defect at the base of tongue and the entrance of

neopharynx that resembles an epiglottis (Fig 27).
The fold is more prominent when the patient
swallows and may narrow the entrance of the
neopharynx and obstruct the bolus transit from
the mouth. Increased intrabolus pressure proxi­
mal to the obstruction contributes to the forma­
tion of a proximal pocket, where residue and food
may accumulate (27).

Anterior Pharyngeal Pouches
Anterior pharyngeal pouches are pockets or out­
pouchings located at the anterior wall between
the base of tongue and the neopharynx entrance.
The mechanism of formation is multifactorial,
including a localized weakness due to absence
of a muscular layer and/or increased intrabolus
pressure against a more distal mechanical or
functional obstruction. Radiologic images show
an anterior outpouching at the entrance of the
neopharynx with contrast material pooling after
the swallow (Fig 28). If the pouch enlarges con­
siderably, it may extend into the skin, creating a
pharyngo­cutaneous fistula (36).

Neopharyngeal Dysmotilities
Neopharyngeal dysmotilities may be secondary to
resection of the laryngeal and pharyngeal struc­
tures that support the tongue and pharyngeal
muscles and/or due to damage of the pharyngeal
muscles and nerves by the tumor, surgery, or
radiation therapy. Dysmotilities are seen on im­
ages from swallowing studies as a limited thrust
of the base of tongue and/or pharyngeal walls,

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Figure 25.  Surgical technique for laryngectomy. (A) Illus-
tration shows the anatomic structures that will be removed
as the hyoid bone, epiglottis, thyroid cartilage including the
vocal folds, cricoid cartilage, and first tracheal ring. (B) Illus-
tration shows the closure of the anterior wall with mucosa,
muscles, and skin for the reconstruction of the neopharynx.
(C) Illustration shows the creation of a tracheoesophageal
fistula, with placement of a one-way prosthesis (arrow) for
voice reconstitution.

with weakening of the pharyngeal propulsion,
impaired coordination of peristalsis, reversed
peristalsis, and outflow resistance across the
PES (Fig 29). Because of neopharyngeal dys­
motility, bolus transit time is prolonged, and
pharyngeal clearance is incomplete, with stasis
and residue (27,36).

total

Figure  26.  Sinus  tract  in
a  78-year-old  man.  Lateral
radiograph  of  swallowing
after
laryngectomy
shows  a  leakage  from  the
proximal  neopharynx  into
the  anterior  soft  tissues  of
the neck (arrow).

Dysfunctions of PES
Dysfunctions of the PES should be evaluated
during and after swallowing during voice gen­
eration. Fluoroscopically, they are seen as an
insufficient or delayed opening or early closing
of the PES (Fig 30). These findings may be a
consequence of impaired pharyngeal propul­
sion or increased resistance at the bolus passage
through the PES due to resection of the cri­
coid cartilage or fibrosis secondary to radiation
therapy (27,36).

Benign Strictures
Benign strictures of the neopharyngeal lumen are
secondary to surgical scarring and/or chemo­

therapy and radiation therapy. The strictures may
partially or completely obstruct the bolus flow,
distending the proximal lumen and retaining ma­
terial the patient swallows (Fig 31) (37).

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Carbo et al  1747

Figure  27.  Pseudoepiglot-
tis  in  a  78-year-old  man  who
underwent  a  total  laryngec-
tomy. Lateral radiograph dur-
ing swallowing shows a linear
horizontal filling defect in the
anterior  wall  of  the  proximal
neopharynx  that  resembles
the  epiglottis  and  partially
obstructs  the  passage  of  the
bolus (arrow).

Figure
28.  Anterior
pharyngeal  pouch  in  a
72-year-old woman. Lat-
eral  radiograph  shows
contrast material pooling
in an outpouching at the
base of the tongue at the
entrance of the neophar-
ynx (*).

Figure 29.  Neopharyngeal dysmotility in a 70-year-old man. Se-
quential lateral radiographs of swallowing show a premature clo-
sure of the neopharynx during the passage of the bolus (arrows in
B), with residue in the proximal lumen.

Figure  30.  PES  dysmotility  in  a
72-year-old woman. Lateral radio-
graph  of  swallowing  shows  PES
narrowing  during  the  passage  of
the bolus (arrow).

Complications of Tracheoesophageal
Fistula and Prosthesis
A malpositioned or a too­large prosthesis may
protrude into the lumen of the tracheostoma and
obstruct it (Fig 32A). When the prosthetic flange
is located in the esophageal lumen instead of being
attached to the wall, the flange may cause obstruc­
tion and interference in the passage of the bolus
and in phonation (Fig 32B). A too­short prosthesis
may lead to closure of the fistula, with associated
inflammatory changes. Esophageal contents can
pass around the prosthesis (ie, periprosthetic) and
into the tracheostoma during swallowing, because
the diameter of the prosthesis is too narrow com­
pared with that of the stoma (Fig 32C) or through
the prosthesis because of malfunction (Fig 32D).
The prosthesis should be removed and replaced
after diagnosis of these complications (38–41).

Conclusion
Swallowing is a complex mechanism that involves
at least 37 pairs of striated muscles, five cranial
nerves, and multiple supportive anatomic struc­
tures that are controlled by the central nervous
system (10). As we have discussed in this article,
numerous anatomic and functional abnormali­
ties can impair swallowing and can be detected at
fluoroscopy.

The presence or supervision of a radiologist
during the examination may contribute to cor­
relation of the perceived abnormalities with the
patient’s symptoms and prior treatments and
imaging studies. On the basis of this preliminary
analysis, the radiologist can decide, in conjunc­
tion with the speech­language pathologist, if ad­
ditional images or structures should be included
in the examination before the patient leaves the
radiography department.

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Figure  31.  Postradiation  stric-
ture in a 75-year-old man. Lateral
radiograph  of  swallowing  after
total laryngectomy shows a stric-
ture in the neopharynx (arrows),
with proximal pharyngeal dilata-
tion (*).

Figure 32.  Complications of a tracheoesophageal prosthesis in four patients. (A) Oblique radiograph of swallowing in an 81-year-
old  woman  shows  migration  of  the  prosthesis  (red  arrows)  into  the  lumen  of  the  tracheostoma  (green  double-headed  arrow).
(B)  Oblique  radiograph  in  a  74-year-old  man  after  swallowing  shows  the  esophageal  flange  of  the  prosthesis  (arrows),  which  is
malpositioned in the lumen of the proximal esophagus instead of being attached to the wall. (C) Oblique radiograph in a 79-year-
old patient after swallowing shows contrast material leaking from the esophagus into the tracheal lumen through the surrounding
cephalad margin of the prosthesis (arrows). (D) Oblique radiograph in a 72-year-old man shows contrast material dripping into the
trachea through the lumen of prosthesis (arrow).

The radiologic report should include all de­
tected abnormalities and should not be limited to
description of the visualization of penetration or
aspiration. Because each abnormality has its own
specific therapeutic approach, the description
of radiologic findings and their correlation with
the pathophysiologic mechanisms and possible
causes should be stated clearly in the report. A
meticulous radiologic diagnosis facilitates the
decision making of referring physicians and swal­
lowing therapists.

Information obtained from swallowing exami­
nations is useful to determine the oral capabilities
of the patient and whether they should initiate,
maintain, or discontinue oral intake without risk­
ing development of pneumonia. A good­quality
examination and report not only improve early
diagnosis and treatment of a patient’s swallowing
disorders but also reduce morbidity, mortality,
length of hospital stay, and health care costs.

Acknowledgment.—The  authors  wish  to  acknowledge  Lory
Tubbs, MA, for her contribution with the illustrations.

References

1.  Allen J, Belafsky P. Symptom indices for dysphagia assess­
ment and management. In: Shaker R, Belafsky P, Postma
GN, Easterling C, eds. Principles of deglutition: a multidis­
ciplinary text for swallowing and its disorders. New York,
NY: Springer Science Business Media, 2013; 357–379.
2.  Logeman JA. Instrumental techniques for the study of swal­
lowing. In: Evaluation and treatment of swallowing disorders:
imaging studies. 2nd ed. Austin, Tex: Pro­ed, 1998; 54–61.
3.  Rubesin  SE.  Pharyngeal  morphology.  In:  Ekberg  O,  ed.
Dysphagia. Diagnosis and treatment. 2nd ed. Cham, Swit­
zerland: Springer International, 2019; 351–384.

4.  Ekberg O, Nylander G. Anatomy and physiology. In: Ekberg
O, ed. Dysphagia. Diagnosis and treatment. 2nd ed. Cham,
Switzerland: Springer, 2019; 3–20.

5.  Logeman JA. Anatomy and physiology of normal deglutition.
In: Evaluation and treatment of swallowing disorders. 2nd
ed. Austin, Tex: Pro­ed, 1998; 13–52.

6.  Belafsky  PC,  Lintzenich  CR.  Development,  Anatomy,
and Physiology of the Pharynx. In: Shaker R, Belafsky P,
Postma GN, Easterling C, eds. Principles of deglutition: a
multidisciplinary text of swallowing and its disorders. New
York, NY: Springer, 2013; 165–173.

7.  Jones B. Abnormalities of pharyngeal function. In: Gore RM,
Levine MS, eds. Textbook of Gastrointestinal Radiology.
4th ed. Philadelphia, Pa: Saunders­Elsevier, 2014; 222–236.
8.  Matsuo  K,  Palmer  JB.  Oral  phase  preparation  and  pro­
pulsion: anatomy, physiology, rheology, mastication, and
transport. In: Shaker R, Belafsky P, Postma GN, Easterling

RG  •  Volume 41  Number 6

Carbo et al  1749

C, eds. Principles of deglutition. A multidisciplinary text
of swallowing and its disorders. New York, NY: Springer,
2013; 117–132.

9.  Lang  IM.  Development,  anatomy  and  physiology  of  the
upper esophageal sphincter and pharyngoesophageal junc­
tion. In: Shaker R, Belafsky P, Postma GN, Easterling C,
eds. Principles of deglutition: a multidisciplinary text for
swallowing  and  its  disorders.  New  York,  NY:  Springer,
2013; 235–255.

10.  Rubesin SE. Principles of performing a “modified barium
swallow”  examination.  In:  RSNA  Categorical  Course  in
Diagnostic  Radiology:  Gastrointestinal.  Oak  Brook,  Ill:
Radiological Society of North America, 1997; 7–19.
11.  Logeman JA. Evaluation of swallowing disorders. In: Evalu­
ation and treatment of swallowing disorders. 2nd ed. Austin,
Tex: Pro­ed, 1998; 168–190.

12.  Rubesin SE. Pharynx: normal anatomy and examination
techniques.  In:  Gore  RM,  Levine  MS,  eds.  Textbook
of  Gastrointestinal  radiology.  4th  ed.  Philadelphia,  Pa:
Saunders­Elsevier, 2014; 207–221.

13.  Skucas  J.  Imging  contrast  agents.  In:  Gore  RM,  Levine
MS, eds. Textbook of Gastrointestinal Radiology. 3rd ed.
Philadelphia, Pa: Saunders­Elsevier, 2008; 3–17.

14.  Logeman JA. Disorders of deglutition. In: Evaluation and
treatment  of  swallowing  disorders.  2nd  ed.  Austin,  Tex:
Pro­ed, 1998; 71–119.

15.  Pokieser  P,  Scharitzer  M.  The  clinical  and  radiological
approach to dysphagia. In: Ekberg O, ed. Dysphagia. Diag­
nosis and treatment. 2nd ed. Cham, Switzerland: Springer
International, 2019; 285–315.

16.  Buchholz DW, Bosma JF, Donner MW. Adaptation, com­
pensation, and decompensation of the pharyngeal swallow.
Gastrointest Radiol 1985;10(3):235–239.

17.  Lazarus C. Dysphagia Secondary to the Effects of Chemo­
therapy and Radiation therapy. In: Shaker R, Belafsky P,
Postma GN, Easterling C, eds. Principles of deglutition. A
multidisciplinary text of swallowing and its disorders. New
York, NY: Springer, 2013; 431–444.

18.  Dantas RO. Cricopharyngeal bar. In: Shaker R, Belafsky P,
Postma GN, Easterling C, eds. Principles of deglutition. A
multidisciplinary text of swallowing and its disorders. New
York, NY: Springer, 2013; 509–514.

19.  Massey  BT.  Crocopharyngeal  achalasia.  In:  Shaker  R,
Belafsky  P,  Postma  GN,  Easterling  C,  eds.  Principles  of
deglutition. A multidisciplinary text of swallowing and its
disorders. New York, NY: Springer, 2013; 515–528.
20.  Easterling C, Shaker R. Upper esophageal sphincter opening
muscle dysfunction. In: Shaker R, Belafsky P, Postma GN,
Easterling C, eds. Principles of deglutition. A multidisci­
plinary text of swallowing and its disorders. New York, NY:
Springer, 2013; 529–538.

21.  Mei L, Sanvanson P. Upper esophageal sphincter restrictive
disorders. In: Bardan E, Shaker R, eds. Gastrointestinal mo­
tility disorders. Cham, Switzerland: Springer, 2018; 79–907.
22.  Lazarus CL, Logemann JA, Pauloski BR, et al. Swallow­
ing disorders in head and neck cancer patients treated with
radiotherapy  and  adjuvant  chemotherapy.  Laryngoscope
1996;106(9 Pt 1):1157–1166.

23.  Born  LJ,  Harned  RH,  Rikkers  LF,  Pfeiffer  RF,  Quigley
EM. Cricopharyngeal dysfunction in Parkinson’s disease:
role in dysphagia and response to myotomy. Mov Disord
1996;11(1):53–58.

24.  Theurer JA, Johnston JL, Taves DH, et al. Swallowing after
right hemisphere stroke: oral versus pharyngeal deficits. Can
J Speech Lang Pathol Audiol 2008;32:114–122.

25.  Lazarus  C,  Logemann  JA.  Swallowing  disorders  in
closed  head  trauma  patients.  Arch  Phys  Med  Rehabil
1987;68(2):79–84.

26.  McCullough  GH,  Kim  Y.  Effects  of  the  Mendelsohn
maneuver on extent of hyoid movement and UES opening
post­stroke. Dysphagia 2013;28(4):511–519.

27.  Rubesin SE. Structural abnormalities of the pharynx. In:
Gore RM, Levine MS, eds. Textbook of gastrointestinal
radiology.  4th  ed.  Philadelphia,  Pa:  Saunders­Elsevier,
2014; 235–265.

28.  Lazarus C. Dysphagia secondary to the effects of chemo­
therapy and radiation therapy. In: Shaker R, Belafsky P,
Postma GN, Easterling C, eds. Principles of deglutition: a
multidisciplinary text for swallowing and its disorders. New
York, NY: Springer Science Business Media, 2013; 431–443.
29.  Cook IJ. Zenker’s diverticulum. In: Shaker R, Belafsky P,
Postma GN, Easterling C, eds. Principles of deglutition: a
multidisciplinary text for swallowing and its disorders. New
York, NY: Springer Science Business Media, 2013; 495–508.
30.  Morrison MP, Postma GN. Surgical treatment of Zenker’s
diverticulum. In: Shaker R, Belafsky P, Postma GN, Easter­
ling C, eds. Principles of deglutition: a multidisciplinary text
for swallowing and its disorders. New York, NY: Springer
Science Business Media, 2013; 847–858.

31.  Agrawal N, Goldenberg D. Primary and salvage total laryngec­
tomy. Otolaryngol Clin North Am 2008;41(4):771–780, vii.
32.  Schindler A, Mozzanic F, Barbiera F. Dysphagia evaluation
and treatment after head and neck surgery and/or chemo­
radiotherapy of head and neck malignancy. In: Shaker R,
Belafsky  P,  Postma  GN,  Easterling  C,  eds.  Principles  of
deglutition:  a  multidisciplinary  text  for  swallowing  and
its  disorders.  New  York,  NY:  Springer  Science  Business
Media, 2013; 649–668.

33.  Giannitto C, Preda L, Zurlo V, et al. Swallowing disorders
after  oral  cavity  and  pharyngolaryngeal  surgery  and  role
of imaging. Gastroenterol Res Pract 2017;2017:7592034.
34.  Wippold FJ II. Postoperative pharynx. In: Gore RM, Levine
MS,  eds.  In:  Textbook  of  gastrointestinal  radiology.  3rd
ed. Philadelphia, Pa: Saunders­Elsevier, 2008; 257–271.
35.  Balfe DM, Koehler RE, Setzen M, Weyman PJ, Baron RL,
Ogura JH. Barium examination of the esophagus after total
laryngectomy. Radiology 1982;143(2):501–508.

36.  Anderson S, Hogan D, Panizza B. Causes and consequences
of  anterior  pharyngeal  pouch  after  total  laryngectomy.  J
Laryngol Otol 2014;128(Suppl 2):S39–S42.

37.  Nguyen NP, Smith HJ, Sallah S. Evaluation and manage­
ment of swallowing dysfunction following chemoradiation
for  head  and  neck  cancer.  Curr  Opin  Otolaryngol  Head
Neck Surg 2007;15(2):130–133.

38.  Logemann JA. Swallowing disorders after treatment of oral
and oropharyngeal cancer. In: Evaluation and treatment of
swallowing disorders. 2nd ed. Austin, Tex: Pro­Ed, 1998;
251–278.

39.  Pope TL, Shaffer HA Jr, Johns ME, et al. Radiologic evalu­
ation  of  the  Blom­Singer  prosthesis  for  vocal  restoration
after  laryngectomy.  Presented  at  the  Annual  Meeting  of
the American Society of Head and Neck Radiology, Los
Angeles, CA, May 1981.

40.  Pauloski BR, Rademaker AW, Logemann JA, Colangelo
LA. Speech and swallowing in irradiated and nonirradiated
postsurgical oral cancer patients. Otolaryngol Head Neck
Surg 1998;118(5):616–624.

41.  Zhang T, Szczesniak M, Maclean J, et al. Biomechanics of
pharyngeal deglutitive function following total laryngectomy.
Otolaryngol Head Neck Surg 2016;155(2):295–302.

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