baseoftongue

Base of the tongue refers to the posterior one-third of the tongue, located in the oropharynx behind the sulcus terminalis and containing the lingual tonsils. It lies opposite the body and is continuous with the pharyngeal mucosa.

The base comprises mucosa, submucosa, and intrinsic and extrinsic tongue muscles; the lingual tonsils are embedded in its mucosa. The base has more limited mobility than the anterior part. Blood supply comes from the dorsal lingual arteries and the tonsillar branch of the facial artery; venous drainage is via the lingual veins to the internal jugular system. Lymphatics drain to deep cervical nodes, notably the jugulodigastric node.

Nerves: Sensory and taste from the posterior tongue are provided by the glossopharyngeal nerve (IX); motor innervation to most tongue muscles is via the hypoglossal nerve (XII), with palatoglossus supplied by the pharyngeal plexus via X. The base participates in swallowing and the gag reflex through IX.

Clinical significance: The base contains the lingual tonsils and can be involved in lingual tonsillitis. It is also a common site for squamous cell carcinoma, often metastasizing to deep cervical nodes; HPV-associated cancers are increasingly recognized. Diagnosis uses endoscopic examination and imaging; treatment depends on stage and may include surgery, radiotherapy, or chemoradiation.

Development: The posterior tongue derives from the hypopharyngeal eminence of the third and fourth pharyngeal arches, distinct from the anterior portion that originates from the first arch.