Hypoglossal nerve

A cranial nerve primarily responsible for controlling tongue movements.

The hypoglossal nerve, known as cranial nerve XII, is primarily responsible for the motor control of the muscles of the tongue. It plays a crucial role in various functions such as speech articulation, swallowing, and the movement of food within the mouth. Unlike many other cranial nerves, the hypoglossal nerve does not carry sensory information, focusing solely on motor functions.

Terminologia Anatomica

nervus hypoglossus

System

Nervous system

Function

The main function of the hypoglossal nerve is to innervate the intrinsic and extrinsic muscles of the tongue. This includes the movements necessary for various activities such as chewing, swallowing, and speaking. The proper functioning of this nerve is essential for articulating sounds clearly, as the tongue shapes and positions itself against the palate and teeth to produce different phonetic sounds. Additionally, during swallowing, the hypoglossal nerve assists in pushing food toward the throat, initiating the swallowing reflex. Damage to this nerve can lead to difficulty in tongue movements, affecting swallowing and speech, which emphasizes its importance in daily functions.

Location

The hypoglossal nerve originates in the hypoglossal nucleus located in the medulla oblongata, at the base of the skull. From there, it extends downwards and exits the skull through the hypoglossal canal. As it travels, it runs lateral to the carotid arteries and jugular vein in the neck region. The nerve then proceeds to the tongue, branching out to innervate the various muscles responsible for tongue movement. This positions it in proximity to key vascular structures and emphasizes its importance in the coordination of oral and swallowing functions.

Did You Know?

The hypoglossal nerve is the only cranial nerve that exclusively operates motor functions related to the tongue.
It can be impacted by various conditions, leading to a clinical presentation known as dysarthria, which affects speech clarity.
In ancient Rome, the artist and anatomist Leonardo da Vinci famously dissected cadavers, providing detailed accounts of the cranial nerves, including the hypoglossal nerve.