Head and neck muscles (chewing, facial, and throat muscles)

Geniohyoid

Musculus geniohyoideus

Origin

Mental spine (inner side of the symphysis) of the mandible

Insertion

Body of the hyoid bone

Function

Pulls the hyoid bone forward and upward; opens the mouth when the hyoid bone is fixed

Innervation

Hypoglossal nerve (CN XII) carrying C1 fibers

Movement & chain

Part of the suprahyoid group; works synergistically with mylohyoid during the oral phase of swallowing and mouth opening.

Palpation

Lies deep to mylohyoid and is difficult to distinguish directly via the floor of the mouth intraorally.

Clinical

Included in surgical procedures to enlarge the upper airway (e.g. genioglossus/geniohyoid advancement in obstructive sleep apnea), since activation pulls the hyoid bone forward and enlarges the pharyngeal space.

Segmental innervation

C1 fibers carried by CN XII, motor.

In clinical practice

Elevates and pulls hyoid bone anteriorly; targeted swallowing therapy (Mendelsohn maneuver) for upper esophageal sphincter opening.

Region in the model

Head and neck muscles (chewing, facial, and throat muscles)