Pterygoideus lateralis

Pterygoideus lateralis

The Pterygoideus lateralis (also known as the lateral pterygoid muscle) is one of the muscles of mastication. It is a short, thick, and somewhat conical muscle located in the infratemporal fossa of the skull. The muscle plays a crucial role in the movement of the mandible (jawbone).

Anatomy

The Pterygoideus lateralis consists of two distinct heads: the superior head and the inferior head.

• Superior head: This head originates from the infratemporal surface and infratemporal crest of the greater wing of the sphenoid bone.
• Inferior head: This head originates from the lateral surface of the lateral pterygoid plate of the sphenoid bone.

Both heads converge and insert into the pterygoid fovea on the anterior surface of the neck of the mandible, as well as the capsule and articular disc of the temporomandibular joint (TMJ).

Function

The primary function of the Pterygoideus lateralis is to assist in the opening of the jaw (depression of the mandible). It also plays a significant role in the protrusion and lateral movement of the mandible, which is essential for chewing and grinding food.

• Bilateral contraction: When both sides of the muscle contract simultaneously, the mandible is protruded.
• Unilateral contraction: When only one side contracts, the mandible moves laterally towards the opposite side, aiding in the grinding motion during mastication.

Innervation

The Pterygoideus lateralis is innervated by the lateral pterygoid nerve, a branch of the mandibular nerve (V3), which is a division of the trigeminal nerve (cranial nerve V).

Blood Supply

The muscle receives its blood supply from branches of the maxillary artery, specifically the pterygoid branches.

Clinical Significance

Dysfunction or spasm of the Pterygoideus lateralis can lead to temporomandibular joint disorder (TMD), which is characterized by pain, restricted movement, and clicking sounds in the jaw. Proper function of this muscle is essential for normal jaw mechanics and overall oral health.

Related Pages

• Muscles of mastication
• Temporomandibular joint
• Mandibular nerve
• Trigeminal nerve
• Maxillary artery
• Sphenoid bone