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Nerve to Medial Pterygoid

nervus musculi pterygoidei medialis

The nerve to medial pterygoid is a branch of the mandibular nerve (V3) given off just below the foramen ovale before the nerve divides into anterior and posterior divisions. It supplies the medial pterygoid muscle from its deep surface and also gives branches to the tensor veli palatini and tensor tympani muscles. Unlike the other muscles of mastication, the medial pterygoid and the two tensor muscles receive their nerve supply from the main trunk of V3 rather than its anterior division.

Region: Head & Skull

Clinical Relevance

Clinical Notes

The nerve to medial pterygoid's supply to tensor tympani and tensor veli palatini through its medial pterygoid nerve branches explains the middle ear and Eustachian tube changes that can accompany mandibular nerve injuries. In trigeminal neuralgia affecting V3, the medial pterygoid and tensor muscles may exhibit involuntary spasm. During coronoid process surgery and medial pterygoid muscle resection for trismus, this nerve must be identified and preserved to maintain jaw closing strength.

Pathology

Common Injuries & Conditions

V3 Trunk Injury at Foramen Ovale

Trauma, tumour infiltration, or skull base surgery at the foramen ovale injures the main mandibular trunk before the nerve to medial pterygoid is given off, producing complete masticatory muscle weakness affecting medial and lateral pterygoid, masseter, and temporalis, with resulting severe trismus, jaw deviation, and difficulty chewing.