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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4547_Библиотеки_им_академика_М_И_Перельмана
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Anatomy and Physiology 7
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Fig. 5 The cricoid cartilage
seen from the left (a) and
anteriorly (b). There are two
articulate surfaces for the
arytenoid cartilages (plain
arrows). There are also
articulate surfaces for the
cricoid cornu of the thyroid
cartilage (crossed arrows)
extends inferiorly and anteriorly in a gap between the
superior and middle pharyngeal constrictors. It partly
joins with the contralateral muscles and extends
inferiorly to insert on the edges of the epiglottis and
also on the posterior margin of the thyroid cartilage
(Figs. 21, 22).
The palatopharyngeal muscle is the biggest of the
elevators. It inserts on the posterior border of the hard
Fig. 6 The thyroid cartilage and cricoid cartilage with the
cricothyroid ligament (shaded)
palate and the palatine aponeurosis and on the pterygoid process. It extends inferiorly and inserts on the
back of the thyroid cartilage and also within the
constrictor musculature (Fig. 15).
musculature of the tongue. These muscle bundles join
and extend posteriorly. They make up the wall of the
pharynx and meet in the midline dorsally in the
pharyngeal raphe (Figs. 17, 18).
The middle pharyngeal constrictor extends from
the hyoid processes and from the stylohyoid ligament.
This ligament runs from the styloid process in the
skull base to the minor processes of the hyoid bone.
It then extends as a plate posteriorly and superiorly,
joining the muscles from the other side in the posterior midline in the pharyngeal raphe (Figs. 18, 19).
The inferior pharyngeal constrictor extends from
the cricoid cartilage, from the thyroid cartilage, and
also from the lateral thyrohyoid ligament (Figs. 17,
18, 19, 20). This muscle extends somewhat superiorly
and posteriorly surrounding the pharynx and joining
the muscle from the other side in a pharyngeal raphe
in the posterior midline. Inferiorly the pharyngeal
constrictors form a superiorly convex arch.
There are several muscles that elevate the pharynx.
The stylopharyngeal muscle extends from the styloid
process and its surroundings at the skull base and
2.2.4 The Pharyngoesophageal Segment
The pharyngeal constrictorsmake up the muscle wall of
thepharynxalmost from the skullbaseanddownintothe
esophagus. Inferiorly to the constrictors there is one
more muscle, namely, the cricopharyngeal muscle
(Zainoetal.1970;Fig. 20).Thismuscleismadeupofan
oblique portion, a transverse portion (which makes up
the bulk of the muscle), and a longitudinal portion of
muscle bundles inferiorly. The oblique part extends
obliquely, superiorly, and posteriorly from the lateral
part of the cricoid cartilage. It is close to the inferior
constrictor. Like the latter muscle, it is usually considered that the oblique muscles connect in the pharyngeal
raphe. This portion of the cricopharyngeal muscle is
anatomically and functionally the inferior (small) portion of the pharyngeal constrictors. The transverse or
semicircular portion extends posteriorly from the posterior and lateral part of the cricoid cartilage. Where the
two muscles merge in the posterior midline there is no
fibrous raphe. The two longitudinal muscles, also called
esophageal elevators,extendfrom the inferior portionof
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Fig. 7 a The thyroid
cartilage and epiglottis (seen
anteriorly) are connected with
the thyroepiglottic ligament.
b The hyoid bone (H) (seen
from the left) is connected to
the epiglottis via the
hyoepiglottic ligament (hl)
Fig. 8 Cricoid cartilage (seen anteriorly). The arytenoid
cartilages (plain arrows) and corniculate cartilages (crossed
arrows) are located on top
the cricoid cartilage and extend on each side of the
esophagus, where they jointhe longitudinal musculature
of the esophagus,which in turns comes from the median
part of the lamina of the cricoid cartilage. Normally the
inferior constrictor muscle overlaps the cricopharyngeal
muscle, which in turn overlaps the circular muscle of the
esophagus (Ekberg and Lindström 1987). However,
between the oblique and transverse part of the cricopharyngeal muscles there is a small triangular gap which
is a weak point called Killian’s opening or Laimer’s triangle. It is through this weak area that the Zenker
diverticulum extends. Laterally, there is a similar weak
point inferior to the transverse portion and above the
insertion of the longitudinal portion of the cricoid muscles. Through this gap the Killian–Jamieson diverticula
extend (Jamieson 1934).
2.3 The Larynx
During swallowing, the larynx acts like a valve that
closes off the airways from the foodway. The closure
of the larynx is achieved by the following mechanisms. The tilting down of the epiglottis is achieved in
a clear-cut two-step fashion. The first movement is
Anatomy and Physiology 9
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Fig. 10 The mandible and hyoid bone seen from below and
anteriorly. The geniohyoid (plain arrow) and stylohyoid
(crossed arrow) muscles are indicated
Fig. 9 The mandible (M), hyoid bone (H), and thyroid
cartilage (T) seen anteriorly. The mylohyoid (plain arrow)
and thyrohyoid (crossed arrow) muscles are indicated
from the upright resting position of the epiglottis to a
transverse position. This movement can be explained
as consequential to the elevation of the hyoid bone
and the approximation between the thyroid cartilage
and the hyoid bone. This movement of the epiglottis is
thereby the result of contraction of the muscles that
elevate the hyoid bone, namely, the stylohyoid, digastric, mylohyoid, and geniohyoid muscles. In addition,
the thyrohyoid muscle approximatesthe hyoid bone and
the thyroid cartilage. The epiglottis is laterally fixed by
the pharyngoepiglottic plicae and, during laryngeal
elevation and thyroid approximation to the hyoid bone,
is tilted to the transverse position with these plicae as
turning points. The second movement of the epiglottis
has been attributed either to the passing bolus which
should push the movable lip of the epiglottis further
down into the esophageal inlet or to the peristaltic
contraction in the pharyngeal constrictor musculature.
It is more probable that the second movement of the
epiglottis is accomplished by one of the muscles that
inserts on the epiglottis. These muscles are the stylopharyngeal, thyroepiglottic, and aryepiglottic muscles.
Noneof these muscleshavesucha directionthattheyare
able to tilt the epiglottis down from its upright resting
position. However, when the epiglottis has attained a
transverse position, the conditions may have changed.
Still, the stylopharyngeal muscle cannot possibly bring
about the second movement, and it is more likely that a
contraction in this muscle results in a tilting back of the
epiglottis to the upright position. It is possible that the
aryepiglottic muscle may be able to pull the epiglottis
downwards against the ‘‘ary’’ region, but never as far
down as into the esophageal inlet. When these two
muscles have been excluded, the thyroepiglottic muscle
remains as an able candidate to accomplish the tilting
down of the epiglottis. With the epiglottis in the transverse position this muscle has a favorable direction in
relation to the epiglottis. A contraction of the thyroepiglottic muscle is therefore very likely to pull the
epiglottis down over the ary region. Furthermore, it will
change the form of the epiglottis from a downward
convexformtoanupwardconvexform.Acontractionof
the aryepiglottic muscle in this new position of the epiglottis with its tip in the esophageal inlet will tighten the
laryngeal inlet in the same manner as the string in a
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Fig. 11 The tongue
musculature, hyoid bone (H),
and styloid process (SP).
a Genioglossus muscle,
b hyoglossus muscle,
c styloglossus muscle,
d composite drawing of the
three muscles shown in a–c
tobacco pouch. It is possible to distinguish two different
steps in the closure of the vestibule, both of which are
clearly separated from the closure of the rima glottidis.
In the first step the supraglottic space of the vestibule is
closedby the appositionof the lateralwalls.Thisclosure
of the supraglottic space is caused by contraction and
thickening of the superior portion of the thyroarytenoid
muscle. The compressed supraglottic space has an orientation in the sagittal plane.
In the second step the closure of the vestibule is
effected by a compression of the subepiglottic space
from below. This is caused by the posterior aspect of
the epiglottis with its superimposed fat cushion that is
gradually pressed against the prominence of the ary
region. The compressed subepiglottic space has an
orientation nearly in the horizontal plane, with its
anterior part more caudally than the posterior part.
The tilting down of the epiglottis is probably due to a
contraction of the thyroepiglottic muscles. A backward
bulging of the superior–anterior wall of the vestibule is
achieved by a folding of the median soft tissue linking
the thyroid cartilage to the hyoid bone. This tissue
comprises the epiglottic cartilage, the preepiglottic fat
cushion, and its bounding ligaments, namely, the thyroepiglottic, the median thyrohyoid, and the hyoepiglottic ligaments. In analogy with other folds in this
region the above structures have been designated ‘‘the
median thyrohyoid fold’’ (Fink 1976).
The described sequence of events in the closure of
the vestibule by a compression from below—the
supraglottic followed by the subepiglottic space—is
important as it implies a peristaltic-like mechanism
that can clear the vestibule of bolus material. After a
swallowing act, the vestibule is free from foreign
particles when it opens again.
The thyroepiglottic muscle and the aryepiglottic
muscles pull the epiglottis downwards over the laryngeal inlet (Fig. 22). The aryepiglottic muscle runs
within thearyepiglottic folds from the ary cartilage in a
superior andanterior direction and inserts on thelateral
border of the epiglottis (Fig. 22). Within the larynx
there are several muscles, namely, the dorsal cricoarytenoid muscles, the lateral cricoarytenoid muscles,
and the arytenoid muscle (Figs. 23, 24). The dorsal
cricoarytenoid muscle runs from the posterior surface
of the cricoid cartilage superiorly and laterally to insert
on the lateral and inferior corner of the arytenoid
cartilage. The lateral arytenoid muscle runs from the
lateral part on the cricoid cartilage superiorly and
posteriorly to insert in the same area as the prior
described muscle. The arytenoid muscle runs between
the two arytenoid cartilages and has a pars recta and
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Fig. 12 Internaltonguemusculature.Thetongueseenaanteriorlyandbfrom theleft.TLtransverse lingual muscles, VLverticallingual
muscles, LS longitudinal superficial muscle, LP longitudinal deep muscle, GP glossopharyngeal muscle, SG styloglossus muscle
Fig. 13 Levatorvelipalatinimuscle(shaded). The pictureshows
the skull base with choanae (dark) as well as the carotid canal
(CC). The uvula (UV) and the faucial arcs (FA) are indicated
also a pars obliqua (Fig. 24). The thyroarytenoid
muscle runsfrom theinside of the lamina of the thyroid
cartilage and runs dorsally and laterally to insert on the
arytenoid cartilage (Fig. 25a). It creates a muscle plate
that laterally covers the larynx and the inlet to the larynx. The inferior portion is more bulky and it is made
up of a lateral part and a vocal part. This latter is often
Fig. 14 Tensor veli palatini muscle (shaded). The picture
shows the skull base with choanae (dark) as well as the carotid
canal. The pterygoid process (P) and the hamulus of the
pterygoid process (H) are indicated, as are the uvula (UV) and
the faucial arcs (FA)
called the vocalis muscle within the vocal folds. The
somewhat weaker and superior portion of the thyroarytenoid muscle is sometimes called the ventricularis
muscle because it forms the ventricular fold. The thyroarytenoid muscle closes the rima glottidis and at
the same time compresses the inferior portion of the
laryngeal vestibule which we callthe supraglottic space.
The cricothyroid muscle is a strong muscle that runs
between the cricoid and thyroid cartilages. The pars
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Fig. 16 The pharyngeal arches seen anteriorly. The locations of
the palatopharyngeal and glossopharyngealmusclesare indicated
muscle. This fold is called the pharyngoepiglottic
fold. The two valleculae are separated in the midline
by a mucosal fold, the median glossoepiglottic fold
(Figs. 26, 27).Thetongue base and valleculae contain a
rich network of lymphatic tissue. The vallecula may
also contain vessels in the submucosa, which causes a
weblike appearance (Ekberg et al. 1986). Further infe-
Fig. 15 The palatopharyngeal muscle seen posteriorly. SB
skull base, TB tubal cartilage, CO choanae, SP soft palate, UV
uvula, TC thyroid cartilage
riorly (Fig. 27) there is a fold reaching from the lateral
border of the epiglottis to the ary region. The folds
surround the inlet of the laryngeal vestibule. This is the
aryepiglottic fold which harbors the aryepiglottic
recta of this muscle runs superiorly and posteriorly
from the cricoid cartilage and inserts on the thyroid
cartilage. The pars obliqua of the muscle runs from the
cricoid cartilage superiorly and posteriorly to insert on
the inferior cornu of the thyroid cartilage (Fig. 25b).
muscle. There are two small protuberances caudally/
inferiorly due to the cuneiform tubercle superiorly and
the corniculate tubercle inferiorly. Between the two
corniculate tubercles there is a cleft called the interarytenoidincisure.Thearyepiglotticfoldismadeupofthe
aryepiglottic muscle posteriorly and the thyroepiglottic
muscle anteriorly. The lamina of the cricoid cartilage
2.4 The Mucosal Surface
causes an impression of the pharyngeal lumen. On both
sides of these impressions there are two recesses called
The previous sections have described a framework of
the piriform sinuses.
bones, cartilages, ligaments, and muscles, constituting
the oral cavity, larynx, and pharynx. Inside this
framework is the mucous membrane (Figs. 26, 27).
3 Anatomy of the Esophagus
The posteriorpart of the tongue reaches all thewayto
the vallecula. This corresponds to the level of the hyoid
bone. There is a pocket on each side of the midline, the
vallecula. Posteriorly and laterally the valleculae are
bordered by a mucosal fold above the stylopharyngeal
The esophagus can be divided into different parts
according to the surrounding anatomical structures
(Fig. 28). The superior part, the pharyngoesophageal
segment (functional term), also called the upper
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Fig. 17 The pharyngeal
musculature seen posteriorly.
a Palatopharyngeal muscles
and elevator of the pharynx.
b Constrictor muscles.
(Drawing by Sigurdur
V. Sigurjonsson)
Fig. 18 The pharynx seen from the left. (Drawing by Sigurdur
V. Sigurjonsson)
Fig. 19 The hyoid bone, thyroid cartilage, and cricoid carti-
lage with muscles and membranes seen from the left
esophageal segment (anatomical term), corresponds
to the cricopharyngeal muscle and surrounding pharynx and cervical esophagus. This is also called
introitus esophagi or Killian’s mouth. From here to
the impression of the aorta is the paratracheal
esophagus (Fig. 28). This is located close to the
membranous part of the trachea. The aorta makes a
short impression from the left into the aortic lumen.
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Fig. 21 The pharyngeal musculature seen posteriorly and with
Fig. 20 The cricopharyngeal muscle seen from posteriorly and
from left. (Drawing by Sigurdur V. Sigurjonsson. From Ekberg
and Nylander 1982)
the right side of the pharynx cut open so that it can be seen from
inside. The three constrictor muscles are overlapping. The
stylopharyngeal muscle runs from the styloid process inferiorly
to insert on the epiglottis, thyroid cartilage, and pharyngeal wall
through a gap between the superior and middle constrictors.
(Drawing by Sigurdur V. Sigurjonsson)
Inferiorly to this and above the left main bronchus is
the aortobronchial portion, which is a short, relatively
wide segment. The left main bronchus makes a short
impression in the esophagus from the left. The cardial
are both sympathetic and parasympathetic nerves.
There is a close proximity between the vagus nerve
and the esophagus, especially inferiorly.
portion is that segment of the esophagus which is
located close to the left atrium of the heart. A schematic drawing of the gastroesophageal region is given
in Fig. 29.
4 Neuroanatomy and Physiology
of Swallowing
The esophagus is made up of three layers, the
mucosa, the submucosa, and the muscularis (Fig. 30).
The mucosa is made of squamous cell epithelium.
Under the epithelium there is a submucosal layer of
musculature as everywhere else in the alimentary
canal. The mucosa also contains glands and vessels.
The mucosa has a tendency to create longitudinal
mucosal folds.
The esophagus has two layers of muscles, an inner
circular and an outer longitudinal muscle layer. The
longitudinal muscles insert on the posterior aspect of
the lamina of the cricoid cartilage. The upper third of
the esophagus is made up of striated musculature,
whereas the lower two thirds is smooth muscles. The
transitional zone, however, has a varying position.
The circular muscle layer is thinner cranially and
increases in thickness distally. Between the two
muscle layers there are a multitude of neurons in a
plexus formation (Auerbach’s plexus). In this there
There are several reviews on the neuroanatomy and
neurophysiologyof swallowing, the mostcontemporary
by Miller (1999). Several of the cranial nerves are
involved in the control of swallowing (Perlman and
Christensen 1997). Oral sensation is transmitted in the
trigeminal nerve. Efferent information in the trigeminal
nervegoestothe mylohyoidmuscle,the anteriorbellyof
the digastric muscle, and the four muscles of mastication: the masseter, temporalis, and pterygoid muscles.
Taste sensation is mediated in the facial nerve.
Efferent control from the facial nerve goes to the
salivary glands and to muscles of facial expression,
the stylohyoid and platysma muscles, as well as the
posterior belly of the digastric muscle.
The glossopharyngeal nerve conveys taste information from the posterior part of the tongue. It also
conveys sensation from the pharynx. It innervates
only the stylopharyngeal muscle efferently.
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Fig. 22 The stylopharyngeal
muscle and epiglottic
musculature seen posteriorly
(a), posteriorly and from the
right (b), and from the right
(c). (Drawing by Sigurdur
V. Sigurjonsson. From Ekberg
and Sigurjonsson 1982)
Fig. 23 The cricoid
cartilage, arytenoid cartilage,
and muscles seen from the left
(a) and posteriorly (b)
Fig. 24 The cranial portion of the cricoid cartilage, the
arytenoid cartilage, and muscles seen posteriorly
The vagus nerve is the most important nerve for
swallowing. It innervates the pharyngeal and laryngeal
mucosa. The recurrent laryngeal nerve conveys sensation from below the vocal folds and also the esophagus.
Efferent control in the vagus nerve comes from the
ambiguus nucleus (striated muscle) and the posterior
nucleusof the vagus nerve (smooth muscles and glands).
The hypoglossal nerve provides efferent control of
all the intrinsic and some of the extrinsic muscles of
the tongue.
The locations of the central swallowing pathways
include several cortical and subcortical regions. One
such area is located immediately in front of the precentral sulcus cortex. Stimulation in this area evokes
mastication followed by swallowing. It is likely that
the cortical and subcortical areas merely modify
swallowing as pharyngeal and esophageal swallowing
can be evoked also in the absence of these areas. This
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Fig. 25 a The larynx cut
open in the midline and seen
from the left. b The larynx
seen anteriorly and from the
left
Fig. 26 The pharynx seen from the left
indicates that the brainstem is the primary swallowing
area.
Afferent information from the oral cavity and
pharynx is mediated via the vagus nerve and other
nerves to the nucleus of the solitary tract in the
brainstem. Close to the nucleus of the solitary tract is
an afferent swallowing center that interprets the
information. If it is found appropriate for swallowing,
information goes to a swallowing center close to the
ambiguus nucleus. Control of the pharynx is managed
from that swallowing center. Information also
goes to a dorsal swallowing center close to the posterior nucleus of the vagus nerve. The oral stage of
Fig. 27 The pharynx cut open in the posterior midline and
seen from behind
swallowing is completely voluntary, whereas the pharyngeal stage of swallowing is automatic. This
automatism means that there is a none-or-all situation.
Once the pharyngeal swallow has been elicited, it is
always completed. It is not modified during the pharyngeal swallowing process and it cannot be interrupted. Swallowing has priority over other activities
controlled from the ambiguus nucleus such as breathing, speech, and positioning. The esophageal stage of
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