CorpusHuman Anatomy
RespiratoryRegion

Oropharynx

Pars oralis pharyngis

Also known as: mesopharynx

The middle part of the pharynx, behind the mouth, from the soft palate to the upper border of the epiglottis, carrying both air and food and housing the palatine and lingual tonsils.

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Overview

The oropharynx communicates anteriorly with the oral cavity through the oropharyngeal isthmus (bounded by the palatoglossal arches) and lies opposite C2–C3. Its anterior wall is the posterior one-third (pharyngeal part) of the tongue with the lingual tonsil; the paired valleculae lie between the tongue base and epiglottis, separated by the median glosso-epiglottic fold. Each lateral wall contains a palatine tonsil in the tonsillar fossa between the palatoglossal (anterior) and palatopharyngeal (posterior) arches, with the superior constrictor forming the fossa's bed.

It is lined by non-keratinised stratified squamous epithelium that withstands the passage of food. Because it is bounded by soft tissue, it can collapse — the key site of obstruction in obstructive sleep apnoea.

Location

Behind the oral cavity, between the soft palate and the upper border of the epiglottis (≈C2–C3).

Parts & subdivisions

  1. Palatine tonsils
    Paired lymphoid masses in the tonsillar fossae; deep crypts; supplied mainly by the tonsillar branch of the facial artery; drain to the jugulodigastric node.
  2. Valleculae
    Paired pits between tongue base and epiglottis; where the tip of a curved (Macintosh) laryngoscope blade is placed.
  3. Lingual tonsil
    Lymphoid nodules over the posterior third of the tongue.

Anatomy

Innervation

Sensory: glossopharyngeal nerve (CN IX), which is the afferent limb of the gag reflex. Motor: vagus via the pharyngeal plexus.

Arterial supply

Tonsillar and ascending palatine branches of the facial artery; dorsal lingual arteries; ascending pharyngeal artery.

Venous drainage

Pharyngeal plexus; the external palatine (paratonsillar) vein is a source of post-tonsillectomy bleeding.

Lymphatic drainage

Jugulodigastric (upper deep cervical) nodes.

Histology

Non-keratinised stratified squamous epithelium; tonsillar crypts lined by reticulated epithelium.

Function

  • Shared passage for air and swallowed food.
  • Initiates the involuntary pharyngeal phase of swallowing and the gag reflex (sensory CN IX).
  • Immune defence via palatine and lingual tonsils.

Clinical significance

Tonsillitis and quinsy

Acute tonsillitis (viral or group A Streptococcus) may form a peritonsillar abscess (quinsy): severe unilateral pain, trismus, "hot-potato" voice and deviation of the uvula away from the affected side; requires drainage.

HPV-associated oropharyngeal cancer

Squamous cell carcinoma of the tonsil and tongue base is increasingly linked to HPV-16, often presenting as a cystic neck node in a younger non-smoker, with a better prognosis than HPV-negative tumours.

Compiled from standard anatomy and physiology references — see the Respiratory System sources. For education only; not medical advice.