Posterior part of tongue

The posterior part of tongue refers to the posterior one-third part of tongue (a.k.a. the root or pharyngeal part of the tongue), which lies within the oropharynx posterior to the sulcus terminalis. It is relatively fixed compared to the anterior two-thirds and is attached to the hyoid bone and mandible by the extrinsic tongue muscles.

Lingual tonsil

The mucosa of the posterior part of tongue contains numerous lymphoid nodules forming the lingual tonsil, an important component of Waldeyer's ring. Unlike the anterior part, the posterior tongue lacks prominent papillae.

Innervation

• Posterior part of tongue is supplied by the glossopharyngeal nerve (CN IX) for both general sensation and taste.

• The posterior-most region near the epiglottis also receives sensory fibres from the internal laryngeal branch of the superior laryngeal nerve (vagus nerve; CN X).

• Motor innervation to tongue muscles is mainly via the hypoglossal nerve (CN XII).

Vasculature and lymphatics

Blood supply is derived from the lingual artery, and lymphatic drainage passes chiefly to the deep cervical lymph nodes, especially the jugulodigastric nodes.