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Pharynx
Anatomy lec # 20
26-4-2011
It’s a funnel-shaped musculomembranous tube, about 15 cm long.
It’s wide superior and narrow inferior, extending from base of the skull to
esophagus, at the lower border of cricoid cartilage at the level of C6.
There are three cavities ant. to pharynx:
1- nasal cavity
2- oral cavity
3- pharyngeal cavity
and that’s why the interior of pharynx is divided into 3 parts:
1-nasopharynx, behind nasal cavity.
2- oropharynx, behind oral cavity.
3-laryngeopharnx (or hypopharynx ), behind larynx.
Lateral view of the pharynx shows that it consists of muscles originate anteriorly
or posteriorly and surround it.
*superior constrictor
* middle constrictor
*inferior constrictor
(constrictor= circular)

Pharyngeal wall consists of layers from in to out:
a-mucosa
b-submucosa
c-fibrous layer
d-muscle layer (musculosa)
although pharynx is part of GI but it consists of inner longitudinal
and outer circular, unlike GI which consists of inner circular and
outer longitudinal.
e-areolar layer (outermost)
it’s a loose connective tissue layer that helps pharynx to push food
while swallowing.
Parts of pharynx:
1- nasopharynx:
it’s located behind nasal cavity.
Floor: superior surface of soft palate.
Roof: -body of sphenoid
- Clivus (basilar part of occipital bone)
- Pharyngeal tonsils (or adenoids)
Enlarged adenoids are chief cause of snoring in children, and when enlarged
should be removed because snoring means difficulty in breathing.
(adenoidectomy: surgical removal of adenoids)
Anterior: choana.
Posterior: C1 (arch of atlas)
Lateral: -opening of Eustachian tube(= auditory tube, which is a tube that
connects nasopharynxs with middle ear and It equalizes the pressure on both
sides of ear drum. The part of the tube proximal to the middle ear is made of
bone; the rest is composed of cartilage.)
-tubal elevation (of auditory tube) which is the origin of tensor villi palatini.
-salpengeopharyngeal fold containing salpingeopharyngeal muscle.
(salping = tube)
-pharyngeal recess which is a space behind tubal elevation.
All nasopharynx is supplied by maxillar n.
2-oropharynx:
it’s located behind the oral cavity
bounded anteriorly by: -oropharyngeal isthmus (which is formed by palatoglossal
fold).
Post.: C1, C2 vertebrae.
Sup.(roof): inf surface of soft palate.
Inf. (floor): by post 1/3 of tongue and the space ant. to epiglottis with it’s
contents : -median glossoepiglottic fold.
-lateral glossoepiglottic fold.
-valecula (the space between the two folds).
Lat:- palatoglossal arch and it’s muscle.
-palatopharyngeal arch and it’s muscle.
- tonsillar fossa (between the two folds) containing palatine tonsils.
N. supply: all oropharynx is supplied by glossopharyngeal n. except valecula
and ant. surface of epiglottis which are supplied by internal laryngeal n. (a branch
from vagus).
Palatine tonsils:
-They are sited between the palatoglossal fold and palatopharyngeal fold.
-They are large in children and small in adults.
-First defence line of pharynx against infection (in childen they are easily enlarged and
inflamed )
Kissing tonsils
very enlarged and inflamed tonsils causing snoring and
difficulty in breathing and swallowing.
Recurrent tonsillitis ( recurrent means happens more than 3 times per year) is
treated by tonsillectomy; what we care about in tonsillitis is the microbe causing the
inflammation “ staphylococcus aureus” because if swallowed it may go to GI then
targeted either to the heart ( specifically to valves) or joints and cause what we call
Rheumatism.
Arterial supply: tonsillar art. Which is branch from facial art.
Venous drainage: they finally go to internal jogular v.
Lymph drainage: jugulodigastric lymph nodes (which are located close to the
mandible) and these finally will drain into deep cervical lymph nodes.
3-Laryngeopharynx:
Bounded ant by: - laryngeal inlet and mucus membrane post.to the larynx.
Post: -C3, C4, C5, C6 vertebrae.
Roof: -sup border of epiglottis.
Inf: -lower border of cricoid.
Lat: -thyroid cartilage
- piriform fossa: which is a recess (blind space or pocket like
space) that’s located on both sides of laryngeal inlet and it’s a
common site of foreign body impactions. Eg: fish bone.
N. supply: int. laryngeal n. ( a branch from sup laryngeal n. which is a branch
from vagus that’s originally branch from accessory).
Pharyngeal muscles:
They are arranged into two groups:
(1) constrictors.
(2) Longitudinal.
Constrictors: -They are 3 in # (sup. Constrictor, mid. constrictor, inf.
Contrictor).
- They are external in position with circular muscle fibers, and
they contribute to pharyngeal wall.
- They overlap each other like a telescope, thus the sup. one is
the innermost and the lower one is the outermost.
- Each one is fan-shaped, and has a narrow ant. end and a wide
post. end that’s inserted (with it’s fellow on the other side) in
the pharyngeal raphe. ( a raphe extending from base of skull
and serves as origin and insertion for several of the pharyngeal
constrictors).
**Function: they narrow (constrict) the pharynx during swallowing from up
to bottom in sequence (sup. then mid. then inf.) around the bolus of food.
Longitudinal muscles (elevators):
- They are internal and have longitudinal muscle fibers.
- They are named according to origin.
- They descend to insert into the pharyngeal wall.
- They are 3 in #: *stylopharyngeus.
*palatopharyngeus.
*salpingeopharyngeus (extending from
Eustachian tube to wall of pharynx).
**All muscles of pharynx are supplied by branches of pharyngeal plexus, which is
located on the lat. wall of mid. constrictor muscle, ( pharyngeal branch of
glossopharyngeal n. , pharyngeal branch of vagus n. , pharyngeal branch of symp. )
Except stylopharyngeus muscle by glossopharyngeal n.
Farah Isamil