mylohyoid

The mylohyoid is a paired, flat, triangular muscle that forms the floor of the mouth. Each muscle runs from the inner surface of the mandible to the body of the hyoid bone, and the two sides meet at the midline where a raphe connects them.

Originating from the mylohyoid line on the inner surface of the mandible near the molar teeth, the fibers course posteromedially to insert into the body of the hyoid bone and the greater horn. The two muscles are joined at the midline raphe.

Innervation is via the nerve to mylohyoid, a motor branch of the inferior alveolar nerve (branch of V3). Blood supply comes mainly from the mylohyoid artery (a branch of the inferior alveolar artery) and the submental artery, with possible contributions from adjacent vessels.

Functionally, the mylohyoid helps form the floor of the mouth and elevates the floor of the mouth and the hyoid bone during swallowing and speaking. When the hyoid bone is fixed, it can assist in depressing the mandible. The muscle lies on the floor of the mouth, with the sublingual gland resting on its superior surface and the submandibular gland lying inferior to it; posteriorly it relates to the digastric muscle and the lingual structures.

Clinically, the mylohyoid is relevant in swallowing and in the anatomy of the submandibular and sublingual spaces, influencing the spread of infections and serving as a landmark in submandibular region surgeries. Injury to the nerve to mylohyoid can affect the function of the anterior belly of the digastric and swallowing mechanics.