ENT Anatomy - Pharynx Part I

The Pharynx is subdivided into three sites:
1. The Nasopharynx
2. The Oropharynx
3. The Hypopharynx





1. The Nasopharynx

The Nasopharynx is located posterior to the nasal cavity choanae (anterior border). It is bounded superiorly by the sphenoid sinus and inferiorly by the soft palate. The posterior wall overlies the base of skull including the clivus and atlas. The lateral walls are the nasopharyngeal mucosa. Located on the lateral walls is the Taurus Tubarius, which is the opening of the Eustachian Tube. Posterior to this is Rosenmueller's Fossa, which is a common site of origin for nasopharyngeal cancers. The roof of the nasopharynx is lined with adenoid lymphatics, which are a component of Waldeyer's ring.


The nasopharynx is innervated by the Glossopharyngeal Nerve (CN IX) and the Maxillary Nerve (CN V2).

Multiple foramen in this region act as potential points of entry for nasopharyngeal cancers. Notably the Foramen Lacerum, which allows entrance into the middle cranial fossa. Other foramen include Foramen Jugulare, Foramen Ovale, Foramen Spinosum, the Carotid Canals and the hypoglossal canals




2. The Oropharynx

The oropharynx is bounded superiorly by the soft palate and inferiorly by the superior aspect of the hyoid bone. The mucosa overlying the C2 and C3 verterbral bodies form the posterior wall. The anterior aspect consists of the anterior palatine pillar and the anterior edge of the soft palate.

The oropharynx consists of 4 subsites:
The soft palate, the tonsillar region, the base of tongue and the pharyngeal walls.

The soft palate includes the uvula. The tonsils are found between the anterior and posterior tonsillar pillars. The base of tongue encompasses the tongue found between the vallecula and the circumvallate papilla.


Lymphatic drainage of this region is primarily to the jugulodigastric lymph node or Level II lymph nodes. Pharyngeal walls are drained by the retropharyngeal. The retropharyngeal nodes consist of a medial and lateral component. The lateral component is also known as Rouviere Nodes. Drainage is primarily unilateral, unless a tumor invades midline structures where it may drain the bilateral cervical chains.

Innervation of this area is primarily via CN IX & X.


3. The Hypopharynx or Laryngopharynx

See next post...