Auriculotemporal nerve

Structure

Origin

The auriculotemporal nerve arises from the posterior division of the mandibular nerve (CN V₃) (which is itself a branch of the trigeminal nerve (CN V)). It arises by two roots that circle around either side of the middle meningeal artery before uniting to form a single nerve.

Course

Roots of the auriculotemporal nerve circle around both sides of the middle meningeal artery before uniting to form a single nerve. The nerve passes deep to the neck of the mandible - between it and the sphenomandibular ligament - and then courses deep to the lateral pterygoid muscle. It issues parotid branches and then turns superiorly, posterior to its head and moving anteriorly, gives off anterior branches to the auricle. It then crosses over the root of the zygomatic process of the temporal bone, deep to the superficial temporal artery. Shortly after the secretomotor parasympathetic fibers branch from the auriculotemporal nerve (parotid branches) to innervate the parotid gland, the auriculotemporal nerve comprises exclusively somatosensory fibers. It ascends to reach the superficial temporal region and innervate its target structures.

The auriculotemporal nerve communicates with the facial nerve (CN VII).

Parasympathetic component

Post-ganglionic parasympathetic secretomotor nerve fibres from the otic ganglion join and "hitch-hike" along the auriculotemporal nerve, leaving the nerve as it passes across the anteromedial surface of the parotid gland to enter and innervate said gland.

Distribution

The auriculotemporal nerve provides sensory innervation to the auricle, external acoustic meatus, outer side of the tympanic membrane and the skin in the temporal region (superficial temporal branches). It also carries a few articular branches that innervate the temporomandibular joint.