Genioglossus (Extrinsic Muscle of Tongue)

Shape and Position: Fan-shaped muscle; constitutes bulk of tongue

Proximal Attachment: Via a short tendon from superior part of mental spine of mandible

Distal Attachment: Entire dorsum of tongue; inferiormost and posteriormost fibers attach to body of hyoid bone

Main Actions: Bilateral activity depresses tongue, especially central part, creating a longitudinal furrow; posterior part pulls tongue anteriorly for protrusion; a most anterior part retracts apex of protruded tongue; unilateral contraction deviates (“wags”) tongue to contralateral side