Hiatus for lesser petrosal nerve

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Base of the skull. Upper surface. (Hiatus for lesser petrosal nerve labeled at center right.)

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The hiatus for lesser petrosal nerve is a small opening in the temporal bone of the human skull. It serves as a passageway for the lesser petrosal nerve, which is a branch of the glossopharyngeal nerve (cranial nerve IX). This nerve carries parasympathetic fibers to the otic ganglion, which then innervates the parotid gland to stimulate saliva production.

Anatomy

The hiatus for the lesser petrosal nerve is located on the anterior surface of the petrous part of the temporal bone. It is situated near the hiatus for greater petrosal nerve, which transmits the greater petrosal nerve. The lesser petrosal nerve exits the skull through the foramen ovale after passing through the hiatus.

Function

The primary function of the lesser petrosal nerve is to carry preganglionic parasympathetic fibers from the inferior salivatory nucleus in the brainstem to the otic ganglion. After synapsing in the otic ganglion, the postganglionic fibers travel with the auriculotemporal nerve to reach the parotid gland, where they stimulate the secretion of saliva.

Clinical significance

Damage to the lesser petrosal nerve or its associated structures can lead to a reduction in saliva production from the parotid gland, potentially resulting in xerostomia (dry mouth). This can occur due to surgical procedures, trauma, or pathological conditions affecting the base of the skull.

Also see

• Glossopharyngeal nerve
• Otic ganglion
• Parotid gland
• Foramen ovale
• Greater petrosal nerve

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  Gray782 updated