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The temporalis muscle is a powerful muscle of the temporomandibular joint that is involved in jaw pain and headaches. It is a fan-shaped muscle with anterior fibres that have a vertical orientation, mid fibres that have an oblique orientation, and posterior fibres that have a horizontal orientation. The temporalis muscle arises from the temporal fossa and the deep part of the temporal fascia, and it passes medial to the zygomatic arch. It forms a tendon that inserts onto the apex and medial surface of the coronoid process of the mandible.
| Characteristics | Values |
|---|---|
| Type | Masticatory muscle |
| Shape | Fan-shaped |
| Orientation | Anterior fibres: vertical; Mid fibres: oblique; Posterior fibres: horizontal |
| Location | On each side of the head; superior to the zygomatic arch; covers the temporal fossa |
| Origin | Temporal fossa; deep part of temporal fascia |
| Insertion | Coronoid process of the mandible |
| Nerve branches | Anterior, middle and posterior deep temporal branches of the anterior trunk of the mandibular nerve (V3) |
| Blood supply | Deep temporal branches of the maxillary artery and middle temporal branches of the superficial temporal artery |
| Function | Facilitates movements of the mandible |
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What You'll Learn
The temporalis muscle's role in chewing
The temporalis muscle is a fan-shaped convergent muscle on each side of the head, covering the temporal bone. It is one of the four primary muscles of mastication, or chewing. The muscle has three sections: anterior, middle, and posterior. Each section has fibres that run in different directions and have different functions.
The anterior fibres of the temporalis muscle have a vertical orientation and function to elevate the mandible, or close the mouth. The posterior fibres have a horizontal orientation and function to retract the mandible. The middle fibres have an oblique orientation and are used for both elevation and retraction of the mandible. A unilateral contraction of the middle fibres provokes lateral movement of the mandible.
The temporalis muscle is the strongest muscle of the temporomandibular joint and is the primary retractor of the mandible. It is innervated by the anterior, middle, and posterior deep temporal branches of the anterior trunk of the mandibular nerve. The muscle receives its blood supply from the deep temporal branches of the maxillary artery and the middle temporal branches of the superficial temporal artery.
The temporalis muscle is involved in jaw pain and headaches. Bruxism, or habitual teeth grinding, and clenching of the jaw can lead to overwork of the muscle, resulting in pain.
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The muscle's structure and shape
The temporalis muscle is a fan-shaped convergent muscle on each side of the head. It fills the temporal fossa, superior to the zygomatic arch, covering much of the temporal bone. The origin point of the muscle spans the entire surface of the fossa below the temporal line, with some fibres also originating from the temporal fascia. The temporalis muscle is divided into two functional parts: the anterior and posterior. The anterior fibres run vertically, and their contraction results in the elevation of the mandible (closing the mouth). The posterior fibres are directed horizontally, and their contraction results in the retrusion of the mandible. The middle fibres run in an oblique direction and are used for both elevation and retraction of the mandible. When these fibres contract unilaterally, they provoke lateral movement of the mandible.
The temporalis muscle is the strongest muscle of the temporomandibular joint and is involved in jaw pain and headaches. It is one of the four primary muscles of mastication (chewing). It is a broad muscle, with its deep surface covering the temporal fossa. Superficially, it is covered by the temporal fascia, masseter muscle, subcutaneous tissue, and skin. The auriculotemporal, facial, and zygomaticotemporal nerves run across the superficial aspect of the muscle.
The temporalis muscle forms a tendon that inserts onto the apex and medial surface of the coronoid process of the mandible. This insertion extends into the retromolar fossa, posterior to the most distal mandibular molar. The tendon runs medial to the zygomatic arch. In other mammals, the muscle usually spans the dorsal part of the skull and may be attached to a sagittal crest.
The temporalis muscle receives its innervation from the anterior, middle, and posterior deep temporal branches of the anterior trunk of the mandibular nerve (V3). It receives its blood supply from the deep temporal branches of the maxillary artery and the middle temporal branches of the superficial temporal artery.
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Innervation of the temporalis muscle
The temporalis muscle is a muscle of mastication (chewing). It is a broad, fan-shaped convergent muscle on each side of the head that fills the temporal fossa, superior to the zygomatic arch. The temporalis muscle can be divided into two functional parts: the anterior and posterior. The anterior portion runs vertically and its contraction results in the elevation of the mandible (closing the mouth). The posterior portion has fibres that run horizontally, and contraction of this portion results in retrusion of the mandible.
The temporalis muscle receives its innervation from the anterior, middle, and posterior deep temporal branches of the anterior trunk of the mandibular nerve (V3). The mandibular nerve is also known as the trigeminal nerve, and the temporalis muscle is supplied by the deep temporal nerves. The muscle receives its blood supply from the deep temporal branches of the maxillary artery and middle temporal branches of the superficial temporal artery.
The temporalis muscle is the strongest muscle of the temporomandibular joint and the primary retractor of the mandible. It is a powerful muscle that facilitates the movements of the mandible. The temporalis muscle is covered by the temporal fascia, also known as the temporal aponeurosis. This fascia is commonly used in tympanoplasty, or surgical reconstruction of the eardrum.
The temporalis muscle is accessible on the temples and can be seen and felt contracting while the jaw is clenching and unclenching. Motor units are recruited the most when they have the maximal leverage, maximising contractile strength.
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Blood supply to the muscle
The temporalis muscle is a fan-shaped muscle on each side of the head that fills the temporal fossa, superior to the zygomatic arch. It is one of the muscles of mastication (chewing) and is the strongest muscle of the temporomandibular joint. The muscle's origin point spans the entire surface of the fossa below the temporal line, with some fibres also originating from the temporal fascia.
The temporalis muscle receives its blood supply from three primary arteries: the anterior deep temporal artery (ADTA), the posterior deep temporal artery (PDTA), and the middle temporal artery (MTA). The ADTA occupies 21% of the anterior region, the PDTA occupies 41% of the middle region, and the MTA occupies 38% of the posterior region. The superficial temporal artery also supplies the muscle from its lateral surface, while the temporal branches of the middle meningeal artery anastomose with the deep temporal arteries, further contributing to the blood supply.
The blood supply to the temporalis muscle is crucial in reconstructive surgery, particularly in the management of arthritic temporomandibular joint (TMJ) disorders. The vascular architecture within the muscle has been studied using techniques such as stereomicroscopy, radiography, and scanning electron microscopy to improve the safety of surgical procedures involving the muscle.
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The temporalis muscle's use in surgery
The temporalis muscle is a powerful muscle of the temporomandibular joint. It is a broad, fan-shaped convergent muscle on each side of the head that fills the temporal fossa, superior to the zygomatic arch. The muscle is involved in jaw pain and headaches, and its overuse can lead to pain. The temporalis muscle can be used in reconstructive surgery of the mouth and face.
During pterional craniotomy, incisions are chosen based on the ease of reattaching the temporalis muscle after the bone fragment is replaced. The temporalis muscle is also used in the reconstruction of the paralysed face and in defects involving the skull base, orbit, midface, and oropharynx. The insertion of the temporalis muscle into the orbicularis oris allows for trigeminal-controlled lower face movement.
The temporoparietal fascia and the temporalis muscle have been used extensively to reconstruct and rehabilitate the paralysed face. Its proximity to the orbit and anterolateral skull base has allowed its use in skull base reconstruction and orbital cavity obliteration. The temporalis muscle is also used in tympanoplasty, or the surgical reconstruction of the eardrum.
The temporalis muscle is the primary retractor of the mandible. The contraction of the posterior fibres of the muscle results in the backward movement of the mandible, while the contraction of the anterior fibres moves the mandible dorsocranially. In unison, these actions facilitate the closing of the mouth and the approximation of teeth.
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Frequently asked questions
The temporalis muscle is a masticatory muscle that facilitates the movements of the mandible, or jaw. It is a fan-shaped convergent muscle on each side of the head that fills the temporal fossa.
The temporalis muscle arises from the temporal fossa and the deep part of the temporal fascia. It forms a tendon that inserts onto the apex and medial surface of the coronoid process of the mandible.
The temporalis muscle is the strongest muscle of the temporomandibular joint and is involved in the elevation and retraction of the mandible, or jaw. It is also likely to be involved in jaw pain and headaches.
The temporalis muscle can be palpated over the temple at the hairline, anterior to the ear and superior to the zygomatic bone.
