A fan-shaped muscle that arises from the temporal fossa and the fascia over it and narrows to a tendon inserting on the coronoid process of the lower jaw
Temporalis — one of the four muscles of mastication.
Anatomy · Muscles
Temporalis
The fan-shaped muscle of the temple
Head · muscle of mastication
A broad, fan-shaped muscle that fills the temporal fossa on the side of the skull and narrows to a strong tendon passing beneath the cheekbone to the lower jaw. It is one of the four chewing muscles: it closes the mouth, and its rear fibres pull the jaw backwards. You can feel it bulge at the temple when you clench your teeth.
How to spot them
- ▸A fan of fibres spread over the side of the skull, converging on a tendon that runs deep to the zygomatic arch
- ▸Its tendon attaches to the coronoid process of the mandible
- ▸Covered by a tough temporal fascia; supplied by deep temporal nerves from V3
- ▸In many apes the sagittal crest on the skull gives extra room for it
What to know
Its rear fibres run horizontally and pull the closed jaw backwards
Temporalis — retraction of the mandible by the posterior fibres.
Supplied by two deep nerves from the anterior division of the mandibular nerve, V3, running on the inner surface of the muscle
Temporalis — the anterior and posterior deep temporal nerves.
Its tendon slips beneath the cheekbone; when the teeth are clenched the muscle bulges visibly in the temple
Temporalis — it passes deep to the zygomatic arch.
In gorillas a bony ridge along the top of the skull provides extra attachment for the biggest jaw muscle
Temporalis — the sagittal crest of male gorillas and some fossil hominins.
Painful chewing and a tender scalp in an older person can herald an inflammation of the artery running over it, which can cause blindness
Temporalis — jaw claudication in giant-cell arteritis, involving the superficial temporal artery.
Wasting here hollows the sides of the head in severe weight loss or after damage to the nerve that supplies it
Temporalis — its loss hollows the temples.
Key ideas
- It is a fan of fibres pulling in different directions: the front fibres run vertically and close the jaw, the back fibres run horizontally and retract it, so it can help steer the jaw as well as lift it.
- The tough temporal fascia over it is attached to the zygomatic arch, so the muscle acts inside a firm compartment; surgeons use it as a flap to fill defects of the face and skull base.
Quick-fire facts
- •Origin: the temporal fossa (down to the inferior temporal line) and the deep surface of the temporal fascia
- •Insertion: the coronoid process of the mandible and the anterior border of the ramus
- •Action: elevates the mandible; posterior fibres retract it
- •Nerve supply: anterior and posterior deep temporal nerves from the anterior division of the mandibular nerve (V3)
- •Blood supply: deep temporal arteries (branches of the maxillary artery) and the middle temporal artery from the superficial temporal artery
- •It is one of the four muscles of mastication, along with the masseter and the medial and lateral pterygoids
- •The temporal fascia covers it and attaches to the zygomatic arch
- •Large sagittal crests in male gorillas and in robust australopithecines mark a very big temporalis
- •The muscle lies close to the pterion, the H-shaped junction of four skull bones, where the anterior branch of the middle meningeal artery lies just under the bone
- •Its tendon passes deep to the zygomatic arch to reach the coronoid process
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Sources
- TeachMeAnatomy — Temporalis
- TeachMeAnatomy — Muscles of mastication