Terminal sulcus of tongue

The terminal sulcus of tongue (a.k.a. sulcus terminalis) is a V-shaped groove on the dorsal surface of the tongue that separates the anterior two-thirds (body) from the posterior one-third (root) of the tongue. Its apex points posteriorly toward the foramen caecum, a small midline pit representing the embryological origin of the thyroglossal duct. The limbs of the sulcus diverge laterally and anteriorly across the dorsum of the tongue.

The terminal sulcus is an important anatomical and embryological landmark because it marks the junction between the oral part and pharyngeal part of the tongue, which differ in development, innervation, and lymphatic drainage. Anterior to the sulcus, the tongue is supplied mainly by the trigeminal and facial nerves, whereas posterior to it the glossopharyngeal nerve predominates for both general sensation and taste.