Muscles of Mastication medium

Muscles of Mastication

• The muscles of mastication are responsible for the movements of the mandible during chewing and grinding.
• The mandible is able to move in five main ways: protrusion, retraction, elevation, depression, and rotation..
• The muscles of mastication attach to the mandible and allow for its movement.
• Understanding these muscles is important for dentists because inflammation, pain, or dysfunction in these muscles can affect patient management.

Masseter

• The masseter is a thick quadrilateral muscle with two parts: superficial and deep.
• The Masseter originates from the zygomatic arch and inserts onto the ramus of the mandible.
• The masseter acts to elevate the mandible.
• The masseter is supplied by the masseteric nerve, which is a branch of the mandibular nerve.
• The masseter is supplied by the facial and maxillary arteries.

Temporalis

• The temporalis muscle is situated on either side of the head.
• The temporalis originates from the temporal fossa and inserts onto the coronoid process and anterior border of the ramus of the mandible.
• The temporalis acts to elevate and retract the mandible.
• The temporalis is supplied by the deep temporal nerves, which are branches of the mandibular nerve.
• The temporalis is supplied by the superficial temporal and maxillary arteries.

Lateral Pterygoid

• The lateral pterygoid is a short muscle with two heads: upper and lower.
• The upper head of the Lateral Pterygoid originates from the greater wing of the sphenoid bone and the lower head originates from the lateral pterygoid plate of the sphenoid bone.
• The Lateral Pterygoid inserts into the pterygoid fovea on the anterior aspect of the neck of the mandible.
• The Lateral Pterygoid acts to open the mouth, protrude the jaw, and rotate the mandible for side to side movement when acting with the contralateral pterygoid muscle.
• The Lateral Pterygoid is supplied by the lateral pterygoid nerve, which is a branch of the mandibular nerve.
• The Lateral Pterygoid is supplied by the maxillary artery.

Medial Pterygoid

• The medial pterygoid is a thick quadrilateral muscle.
• The medial pterygoid originates from two heads: a large deep head from the lateral pterygoid plate of the sphenoid bone and a small superficial head from the tuberosity of the maxilla and pyramidal process of the palatine bone.
• The medial pterygoid inserts into the medial surface of the ramus and angle of the mandible.
• The medial pterygoid acts to elevate and protrude the jaw.
• The medial pterygoid is supplied by the medial pterygoid branch of the mandibular nerve.
• The medial pterygoid is supplied by the maxillary artery.

Accessory Muscles of Mastication

Digastric

• The digastric has two bellies: anterior and posterior.
• The anterior belly of the digastric originates from the digastric fossa on the mandible and the posterior belly originates from the mastoid process of the temporal bone.
• Both bellies meet above the hyoid bone and are held by connective tissue.
• The digastric acts to depress the mandible and elevate the hyoid bone during chewing and swallowing.
• The anterior belly is supplied by the mylohyoid nerve and the posterior belly is supplied by the facial nerve.
• The anterior belly is supplied by the submental branch of the facial artery and the posterior belly is supplied by the posterior auricular/occipital artery.

Buccinator

• The buccinator muscle makes up the cheek.
• The buccinator originates from the pterygomandibular raphae and the buccal alveolar bone.
• The buccinator inserts into the orbicularis oris muscle at the angle of the mouth.
• The buccinator pulls the corner of the mouth back and compresses the cheek against the buccal surfaces of molars.
• The buccinator is supplied by the buccal branch of the facial nerve.
• The buccinator is supplied by the facial and maxillary arteries.

Geniohyoid

• The geniohyoid muscle is situated above the mylohyoid line.
• The geniohyoid originates from the inferior genial tubercle of the mandible.
• The geniohyoid inserts into the body of the hyoid bone.
• The geniohyoid acts to depress the mandible and elevate the hyoid bone during swallowing.
• The geniohyoid is supplied by the hypoglossal nerve.
• The geniohyoid is supplied by the sublingual branch of the lingual artery.

Genioglossus

• The genioglossus originates from the superior genial tubercle.
• The genioglossus inserts into the dorsum of the tongue.
• The genioglossus acts to depress, retract and protrude the tongue.
• The genioglossus is supplied by the hypoglossal nerve.
• The genioglossus is supplied by the sublingual branch of the lingual artery and the submental branch of the facial artery.