Transcript Human Anatomy تشريح / د . سيف (م 8

‫تشريح ‪ /‬د ‪ .‬سيف (م ‪)9 - 8‬‬
‫ثاني اسنان موصل‬
‫‪2015 / 12 /20‬‬
‫د ‪ .‬سيف (م ‪)8‬‬
‫‪Human Anatomy‬‬
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The Pharynx
The pharynx is the superior expanded part of the alimentary
system situated behind the nasal cavities, the mouth, and the
larynx and may be divided into nasal, oral, and laryngeal
parts. The pharynx is funnel shaped, its upper, wider end
lying under the skull and its lower, narrow end becoming
continuous with the esophagus opposite the 6th cervical
vertebra. The pharynx has a musculomembranous wall, which
is deficient anteriorly.
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Muscles of the Pharynx
The muscles in the wall of the pharynx consist of the superior,
middle, and inferior constrictor muscles, whose fibers run in
a somewhat circulardirection, and the stylopharyngeus and
salpingopharyngeus muscles, whose fibers run in a
somewhat longitudinal direction.
The three constrictor muscles extend around the pharyngeal wall
to be inserted into a fibrous band or raphe that extends from
the pharyngeal tubercle on the basilar part of the occipital
bone of the skull down to the esophagus. The three
constrictor muscles overlap each other so that the middle
constrictor lies on the outside of the lower part of the
superior constrictor and the inferior constrictor lies outside
the lower part of the middle constrictor.
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Parts of the pharynx
A. Nasopharynx: has a respiratory function; it is the posterior
extension of the nasal cavities. The nose opens into the
nasopharynx through two choanae (paired openings between
the nasal cavity and the nasopharynx). The roof and posterior
wall of the nasopharynx form a continuous surface that lies
inferior to the body of the sphenoid bone and the basilar part
of the occipital bone This part lies above the soft palate and
behind the nasal cavities, it consists of no. of structures
which are:
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-Openening of auditory tube: On each lateral wall of the
nasopharynx there is an opening that leads into the auditory
tube. This tube connects the nasopharynx to the middle ear.
-Tubal ridge: Above and behind the opening of the auditory tube the
wall of the nasopharynx shows a bulging called the tubal ridge.
This elevation is produced by the medial end of the cartilaginous
part of the auditory tube.
-Salpingopharyngeal fold: a fold of mucous membrane starting at
the tubal ridge passes down the pharyngeal wall, It covers the
salpingopharyngeus muscle, which opens the pharyngeal orifice
of the pharyngotympanic tube during swallowing.
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-Pharyngeal tonsil: The mucosa of the median part of the roof
shows a bulging produced by a mass of lymphoid tissue. This
lymphoid tissue constitutes the pharyngeal tonsil.
-Tubal tonsil: Some lymphoid tissue is also present behind the
opening of the auditory tube. This collection of lymphoid tissue is
called the tubal tonsil.
-pharyngeal recess : Posterior to the tubal ridge and the
salpingopharyngeal fold is a slit-like lateral projection of the
pharynx, the pharyngeal recess, which extends laterally and
posteriorly.
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B. Oropharynx: has a digestive function. It is bounded by
the soft palate superiorly, the base of the tongue inferiorly,
and the palatoglossal and palatopharyngeal arches laterally. It
extends from the soft palate to the superior border of the
epiglottis.
Contents of oropharynx are:
-Palatoglossal arch:
two ridges or folds of mucous membrane passing from the so
ft palate to the side of the tongue and enclosing the
palatoglossus muscle.
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-Palatopharyngeal arch:
folds of mucous membrane that pass downward from the
posterior margin of the soft palate to the lateral wall of the
pharynx.
It encloses the palatopharyngeus muscle and
forms the
posterior margin of the tonsillar fossa.
-Palatine tonsil:
are masses of lymphoid tissue lies between the palatoglossal
and palatopharyngeal folds. The depression in which the
palatine tonsil lies is called the tonsilar sinus.
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C. laryngopharynx:
lies posterior to the larynx, extending
from the superior border of the epiglottis and the pharyngoepiglottic folds to the inferior border of the cricoid cartilage,
where it narrows and becomes continuous with the
esophagus. Posteriorly, the laryngopharynx is related to the
bodies of the C4– C6 vertebrae. Its posterior and lateral walls
are formed by the middle and inferior pharyngeal constrictor
muscles. Internally, the wall is formed by the
palatopharyngeus and stylopharyngeus muscles. The
laryngopharynx communicates with the larynx through the
laryngeal inlet on its anterior wall.
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Contents of laryngopharynx:
-Epiglottis:
is a thin, leaf-shaped structure at the superior border of the
larynx. In its relaxed position, the epiglottis projects into the
pharynx, or throat, and rests just posterior to the tongue.
-Piriform fossa (recess):
is a small depression of the laryngopharyngeal cavity on either
side of the laryngeal inlet. This fossa is separated from the
laryngeal inlet by the ary-epiglottic fold.
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-Lateral glossoepiglotic fold:
the fold of mucous membrane that extends from the m
argin of the epiglottis to the pharyngeal wall and base
of the tongue on eachside, forming the lateral
bound
ary of the epiglottic valleculae.
-Median glossoepiglotic fold:
the fold of mucous membrane that extends from the
margin of the epiglottis to the pharyngeal wall and base
of the tongue on each side, forming the lateral boundary
of the epiglottic valleculae.
-Vallecula:
a depression immediately posterior to the root of the to
ngue between the median and lateral glossoepiglottic fo
lds.
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Nerve supply of the pharynx
The nerve supply of the pharynx is through the
pharyngeal plexus that is formed by branches from
the glossopharyngeal, vagus and cranial accessory
nerves; and from the sympathetic trunk. The fibers
of the cranial accessory nerve run through the vagus
and constitute the main supply of the muscles of the
pharynx, including that of the soft palate.
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Blood Vessels and Lymphatics of Pharynx
The pharynx receives numerous small branches that arise
from the ascending pharyngeal, lingual, facial and
maxillary arteries. The veins drain into a plexus that
surrounds the pharynx and drains into the internal
jugular and facial veins.
The lymph vessels of the pharynx drain into the deep
cervical lymph nodes. Some of the lymph passes
through the retropharyngeal nodes.
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