Temporalis

Musculus temporalis

Also known as: temporal muscle

A fan-shaped muscle filling the temporal fossa. It elevates the mandible, and its posterior fibres retract it.

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Overview

Temporalis arises from the floor of the temporal fossa (below the inferior temporal line) and the overlying deep temporal fascia. Its fibres converge to a strong tendon that passes deep to the zygomatic arch and inserts on the coronoid process and the anterior border of the ramus of the mandible. Its anterior fibres run almost vertically and are powerful elevators of the mandible (closing the jaw). Its posterior fibres run almost horizontally and retract the protruded mandible, making it the main retractor together with the deep part of masseter.

It is one of the four muscles of mastication, all derived from the 1st pharyngeal arch and supplied by the mandibular division of the trigeminal nerve (V3). You can feel it contract in the temple when you clench your teeth.

Location: Temporal fossa on the side of the skull, deep to the temporal fascia.

Parts & subdivisions

Anterior (vertical) fibres
Elevate the mandible.
Posterior (horizontal) fibres
Retract the mandible and maintain the rest position.

Anatomy

Origin: Floor of the temporal fossa and the deep surface of the temporal fascia.
Insertion: Tip and medial surface of the coronoid process and the anterior border of the ramus of the mandible.
Action: Elevates the mandible (closes the jaw); posterior fibres retract it.
Innervation: Deep temporal nerves (anterior division of the mandibular nerve, CN V3).
Nerve roots: Cranial nerve V3 (trigeminal motor nucleus, pons); no spinal roots
Arterial supply: Anterior and posterior deep temporal arteries (maxillary artery); middle temporal artery (superficial temporal artery).
Relations: Passes deep to the zygomatic arch. Covered by the temporal fascia, to which the superficial temporal vessels and the auriculotemporal nerve are superficial.

Function

Closes the jaw (elevation)
Retracts the mandible
Maintains the rest position of the mandible

Clinical significance

Temporomandibular disorders and bruxism

Tenderness and hypertrophy of temporalis accompany tooth-grinding and TMJ dysfunction. Tension-type headache is often felt over the temple.

Jaw claudication

In giant cell arteritis, ischaemia of the muscles of mastication causes pain on chewing. This is a red-flag symptom requiring urgent steroids to prevent blindness.

Compiled from standard anatomy and physiology references — see the Muscular System sources. For education only; not medical advice.