The Pharynx

The Pharynx

A funnel-shaped muscular tube Extends from the base of the skull to C6 Lies behind

Nasal cavities - NasopharynxOral cavity - OropharynxLarynx - Laryngopharynx

Inferiorly continues with esophagus

Nasopharynx

Oropharynx

LaryngopharynxLarynx

Nasal Choanae

Oropharyngeal Isthmus

Laryngeal Inlet

Adenoid(Pharyngeal tonsil)

Auditory tube

Soft palate

Auditory tube

Wall of the Pharynx

Consists of three layersMucosal layer (mucous membrane)Submucous layerMuscular layer

Mucosal layer

Lined by Nasopharynx – Ciliated columnar epitheliumOropharynx – Stratified squamous epitheliumLaryngopharynx - Stratified squamous

epithelium

Submucous layer

Fibrous layer Thick in the upper part where the muscular

layer is deficient

Muscular layer Consists of

3 Circular muscles 3 Longitudinal muscles

ConstrictorsLongitudinal

SuperiorStylopharyngeus

MiddlePalatopharyngeus

InferiorSalpingopharyngeus

Salpingopharyngeus

Palatopharyngeus

Superior Constrictor

Middle Constrictor

Inferior ConstrictorStylopharyngeus

Salpingopharyngeus

Esophagus

Blood Supply

Branches fromArterial supply:

Ascending pharyngeal a. Superior thyroid a. Ascending palatine from the Facial a. Greater palatine and pharyngeal Maxillary a.

Venous drainage Pharyngeal venous plexus which drains into the

internal jugular vein

Nerve Supply

Sensory Nasopharynx - V2 Oropharynx – Glossopharyngeal nerve Laryngopharynx – Glossopharyngeal and vagus

nerves (Internal and recurrent laryngeal nerves)

Motor All the muscles are innervated by the vagus EXCEPT

stylopharyngeus muscle which is supplied by the IX CN.

Nerve Supply

Pharyngeal nerve plexusFormed by the pharyngeal branches of the

Glossopharyngeal nerve Vagus nerve Sympathetic chain

Lymphatic drainage

To the retropharyngeal LN and then to deep cervical LN

Directly to the deep cervical LN

Retropharyngeal LN

Deep Cervical LN

Tonsils

Four groups of submucous lymphoid collections.Pharyngeal TonsilPalatine tonsilTubal TonsilLingual Tonsil

Adenoid(Pharyngeal tonsil)

Tubal Tonsil

Palatine tonsil

Lingual tonsil

Tonsils