Auriculotemporal nerve

The auriculotemporal nerve is a sensory branch of the posterior division of the mandibular division of the trigeminal nerve.

Gross anatomy

The auriculotemporal nerve divides posteriorly from the posterior division of the mandibular division before dividing into two roots separate to encircle the middle meningeal artery just as it ascends to enter the foramen spinosum. The two roots then rejoin to pass laterally between the neck of the mandible and the sphenomandibular ligament, and then between the temporomandibular joint and the external auditory meatus, giving off small articular branches to the temporomandibular joint. At the upper border of the parotid gland it supplies the sheath of the gland and then terminates as two cutaneous branches:

• an auricular branch which supplies the:
  • external acoustic meatus
  • external surface of the tympanic membrane along with the greater auricular nerve (the internal surface is supplied by the glossopharyngeal nerve)
  • skin of the lateral auricle anterior to the external acoustic meatus. The remainder of the auricle is supplied by the greater auricular nerve (C2, C3)
• a temporal branch which ascends posterior to the superficial temporal vessels over the root of the zygoma to supply the posterior half of the temple, that is the ‘hairy skin’ of the temple; the anterior half of the temple ("skin of the hairless temple” is supplied by the zygomaticotemporal nerve from the maxillary division of the trigeminal nerve)

The auriculotemporal nerve receives sympathetic fibers from the middle meningeal artery and secretomotor parasympathetic fibers (which derive from the otic ganglion) from the lesser petrosal nerve, both of which supply the parotid gland .

There are communicating rami between the auriculotemporal nerve and the facial nerve within the parotid gland .

Radiographic features

The auriculotemporal nerve is usually not seen on CT or MRI. However, the expected course of the auriculotemporal nerve lies parallel to the posterior border of the mandible, just superior to the level of the terminal bifurcation of the external carotid artery into the maxillary and superficial temporal arteries .

Related pathology

• perineural spread of head and neck malignancies (e.g. cutaneous squamous cell carcinoma, salivary gland adenoid cystic carcinoma) can occur along the auriculotemporal nerve, with potential to spread to the facial nerve from the mandibular division (V3) of the trigeminal nerve, or vice-versa .
• Frey syndrome: commonest post-parotidectomy complication