Masticatory muscles

Masticatory Muscles

The four muscles of mastication.

The masticatory muscles or muscles of mastication are the muscles responsible for the chewing and grinding of food, and are essential for speech and facial expressions. They are primarily located in the jaw and face, and are innervated by the mandibular nerve, the third branch of the trigeminal nerve.

Anatomy

There are four primary masticatory muscles: the masseter muscle, the temporalis muscle, the medial pterygoid muscle, and the lateral pterygoid muscle.

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The masseter muscle.

Masseter muscle: The masseter muscle is the most superficial of the four muscles, and is responsible for the elevation of the mandible, or closing of the jaw.

The temporalis muscle.

Temporalis muscle: The temporalis muscle is a broad, fan-shaped muscle located on the side of the skull. It is responsible for the elevation and retraction of the mandible.

The medial pterygoid muscle.

Medial pterygoid muscle: The medial pterygoid muscle is a thick, quadrilateral muscle that acts to elevate the mandible and move it side-to-side.

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The lateral pterygoid muscle.

Lateral pterygoid muscle: The lateral pterygoid muscle is a short, thick muscle that protrudes the mandible and moves it side-to-side.

Function

The masticatory muscles work together to move the jaw in three planes: up and down, side to side, and forward and backward. This allows for the complex movements necessary for chewing and grinding food, as well as for speech and facial expressions.

Clinical significance

Dysfunction of the masticatory muscles can lead to a variety of conditions, including temporomandibular joint disorder, bruxism, and orofacial pain.

See also

• Human musculoskeletal system
• Facial muscles
• Oral and maxillofacial surgery