Pterygoideus externus

Pterygoideus externus

The Pterygoideus externus, also known as the lateral pterygoid muscle, is one of the muscles of mastication. It is a paired muscle located in the infratemporal fossa of the skull. This muscle plays a crucial role in the movement of the mandible (jawbone).

Anatomy

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

Superior Head

The superior head originates from the greater wing of the sphenoid bone and inserts into the articular disc and capsule of the temporomandibular joint (TMJ).

Inferior Head

The inferior head originates from the lateral surface of the lateral pterygoid plate of the sphenoid bone and inserts into the pterygoid fovea on the neck of the mandible.

Function

The primary function of the Pterygoideus externus is to assist in the opening of the jaw. It also plays a role in the protrusion and lateral movement of the mandible, which is essential for chewing and biting.

Innervation

The muscle 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 blood supply to the Pterygoideus externus is provided by branches of the maxillary artery, specifically the pterygoid branches.

Clinical Significance

Dysfunction or spasm of the Pterygoideus externus can lead to temporomandibular joint disorder (TMD), which can cause pain and difficulty in jaw movement. It is often evaluated in patients with bruxism (teeth grinding) and other masticatory muscle disorders.

Related Pages

• Muscles of mastication
• Temporomandibular joint
• Mandibular nerve
• Trigeminal nerve
• Maxillary artery
• Infratemporal fossa