Anatomy
Summary
The hypoglossal nerve, or cranial nerve XII, originates from the medulla and passes through the hypoglossal canal in the posterior cranial fossa. The hypoglossal nerve provides motor innervation to three muscles of the tongue: the genioglossus, the hyoglossus, and the styloglossus. The genioglossus muscle protrudes the tongue, the hyoglossus muscle retracts and lowers it, while the styloglossus pulls up the sides of the tongue. When the hypoglossal nerve is injured, it can cause the tongue to deviate to the affected side due to muscle weakness.
Lesson Outline
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FAQs
Cranial nerve XII, also known as the hypoglossal nerve, supplies motor innervation to three muscles of the tongue: the genioglossus, the hyoglossus, and the styloglossus.
The genioglossus, hyoglossus, and styloglossus are extrinsic muscles of the tongue that are innervated by the hypoglossal nerve. The genioglossus muscle sticks out the tongue, the hyoglossus depresses and retracts the tongue, and the styloglossus pulls up the sides of the tongue.
The hypoglossal nerve begins from the medulla and passes through the hypoglossal canal in the posterior cranial fossa.
