Masseter muscle

Authors

Affiliations

Nathaniel Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

OIAN

Muscle	Origin	Insertion	Nerve	Action
Masseter muscle	/The Archive/Anatomy/Skeletal Muscles/Head and Neck/Muscles of Mastication/masseter.html#origin	/The Archive/Anatomy/Skeletal Muscles/Head and Neck/Muscles of Mastication/masseter.html#insertion	?var:ref-masseter.nerve	/The Archive/Anatomy/Skeletal Muscles/Head and Neck/Muscles of Mastication/masseter.html#action

Origin

SF layer: zygomatic arch (ant 2/3); Deep layer: Zygomatic arch (post. 1/3)¹

Insertion

Mandibular angle (Masseteric tuberosity)¹

Innervation

Trigeminal CN V: Mandibular (V₃)¹

Action

The primary function of the masseter is to develop potentially large forces between the molars for effective crushing of food². This is possible since the force vector of the muscle is nearly perpendicular to the biting surface of the molars². The masseter’s ability to combine ipsilateral excursion (unilateral function) with a strong biting force (Bilateral function) makes it very suitable for grinding food²

SF Fibers: Protrude mandible¹

• Bilateral contraction: Elevation^1,2 and slight protrusion²
  • Elevates the mandible¹ to bring the teeth into contact during mastication²
  • Bilateral action of the masseters also protrudes the mandible slightly.
• Unilateral contraction: Slight I/L excursion²
  • This muscle action is most effective when the mandible is positioned in C/L excursion²
  • This position not only stretches the muscle (presumably augmenting its activation), but also increases its force potential within the horizontal plane.
  • Therefore, this muscle at moving the jaw OUT of C/L excursion and into neutral

Clinical Significance

1.

Gilroy AM, MacPherson BR, Wikenheiser JC, Voll MM, Wesker K, Schünke M, eds. Atlas of Anatomy. 4th ed. Thieme; 2020.

2.

Neumann DA, Kelly ER, Kiefer CL, Martens K, Grosz CM. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 3rd ed. Elsevier; 2017.