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Pharynx & Oesophagus
Head & Neck Unit – Lecture 13
‫ حيدر جليل األعسم‬.‫د‬
The Pharynx
Pharynx is funnel shaped musculo-membranous tube which is deficient
anteriorly and situated behind nasal cavities, mouth and larynx. Thus, it
is divided into nasal, oral & laryngeal parts. Its upper end is wider lying
under the skull and its lower end is narrow and continuous with
esophagus opposite 6th cervical vertebra. It is also continuous with
mucous membrane of tympanic cavity by the auditory tube.
Muscles of the Pharynx
Superior, Middle & Inferior constrictor muscles:
Their fibers run in a circular direction. They
extend around pharyngeal wall to be inserted
into a fibrous band or raphe that extends from
pharyngeal tubercle on basilar part of occipital
bone of skull down to esophagus. They overlap
each other so that middle constrictor lies on
outside of lower part of superior constrictor and
inferior constrictor lies outside lower part of
middle constrictor.
Cricopharyngeus is the lower part of inferior
constrictor arising from cricoid cartilage. Its
fibers pass horizontally around lowest and
narrowest part of pharynx and act as a
sphincter.
Killian's dehiscence is area on posterior
pharyngeal wall between upper propulsive part
of inferior constrictor and lower sphincteric part
(cricopharyngeus).
Stylopharyngeus, Palatopharyngeus and
Salpingopharyngeus :
Their fibers run in a longitudinal direction.
Interior of the Pharynx
Nasal Pharynx (Nasopharynx):
It lies above soft palate & behind
nasal cavities. It has submucosal
collection of lymphoid tissue
called Pharyngeal Tonsil.
Pharyngeal Isthmus is the opening
in floor between soft palate and
posterior pharyngeal wall.
Tubal Elevation is elevated ridge of
the opening of Auditory Tube on
lateral pharyngeal wall.
Pharyngeal recess is a depression
in pharyngeal wall behind tubal
elevation.
Salpingopharyngeal fold is a
vertical fold of mucous membrane
covering Salpingopharyngeus.
Interior of the Pharynx
Oral Pharynx (Oropharynx):
It lies behind oral cavity. Its floor is
formed by posterior 1/3 of tongue and
interval between tongue and epiglottis.
Median Glossoepiglottic Fold is a
midline fold
Lateral Glossoepiglottic Fold lies on
each side of it .
Vallecula is a depression on each side
of median glossoepiglottic fold.
Palatoglossal and Palatopharyngeal
arches are folds on lateral wall of
oropharynx covering Palatoglossus &
Palatopharyngeal respectively and
palatine tonsils lies in between them in
Tonsillar fossa.
Oropharyngeal isthmus is the interval
between the two Palatoglossal arches
and marks the boundary between
mouth & pharynx.
Interior of the Pharynx
Laryngeal Pharynx:
It lies behind the opening into the
larynx. The lateral wall is formed by
Thyroid cartilage and Thyrohyoid
membrane.
Piriform fossa is a depression in
the mucous membrane on each
side of the laryngeal inlet.
Blood Supply of the Pharynx
Ascending pharyngeal Artery
Tonsillar branches of facial
arteries
Branches of maxillary and lingual
arteries
Lymph Drainage of the Pharynx:
Directly into
Deep Cervical Lymph nodes
OR
Indirectly via
Retropharyngeal or
Paratracheal nodes into
deep cervical nodes
Nerve Supply of the Pharynx
Mucous membrane of the pharynx is
supplied as follows:
Nasal pharynx: Maxillary nerve.
Oral pharynx: Glossopharyngeal nerve
Laryngeal pharynx: Internal laryngeal
branch of vagus nerve.
Palatine
Tonsils
They are two masses of lymphoid tissue
located in tonsillar fossa between
palatoglossal and palatopharyngeal arches.
Each tonsil is covered by mucous membrane
on its free medial surface that projects into
the pharynx. The tonsil is covered on its
lateral surface by a fibrous capsule that is
separated from superior constrictor muscle
by loose areolar tissue containing External
palatine vein descends from soft palate.
Lateral to superior constrictor muscle lie
Styloglossus muscle, loop of facial artery, &
internal carotid artery.
Blood Supply:
Tonsillar branch of facial artery.
Veins pierce superior constrictor to join
External palatine, pharyngeal or facial veins
Lymph Drainage: by Upper deep cervical lymph nodes.
Waldeyer's Ring of Lymphoid Tissue
The lymphoid tissue surrounding opening into respiratory and digestive
systems forms a ring. The lateral part of this ring is formed by Palatine
tonsils & tubal tonsils (lymphoid tissue around auditory tube opening).
Pharyngeal tonsil in roof of nasopharynx forms upper part of the ring,
and Lingual tonsil on posterior 1/3 of tongue forms the lower part.
The Esophagus
It is a muscular tube about (25 cm) long, extending from pharynx to
stomach. It begins at the level of cricoid cartilage, opposite the body of
6th cervical vertebra. It commences in midline, but as it descends
through neck, it inclines to the left side.
Relations in the Neck:
Anteriorly:
Trachea and Recurrent
laryngeal nerves (ascend in
between trachea&esophagus
Posteriorly:
Prevertebral layer of deep
cervical fascia, longus colli,
and vertebral column.
Laterally:
lobes of thyroid gland and
carotid sheath.
Blood Supply in the Neck:
Arteries: Inferior thyroid arteries.
Veins: Inferior thyroid veins.
Lymph Drainage in the Neck:
Deep cervical lymph nodes.
Nerve Supply in the Neck:
Recurrent laryngeal nerves &
Sympathetic trunks.
End of the Lecture
GOOD LUCK