Which muscle is the main mover of tongue protrusion?

• A. Stylohyoid
• B. Hyoglossus
• C. Genioglossus
• D. Palatoglossus

Answer: (C)

The main mover of tongue protrusion is the genioglossus. This extrinsic tongue muscle arises from the mandible and fans into the tongue. When both sides contract, especially the posterior portion, the tongue is pushed forward out of the mouth. If only the anterior fibers contract, the tip or the center of the tongue can be depressed or pulled back, which shows how the same muscle can produce different movements depending on which fibers fire. The other muscles listed have different roles: one helps move the hyoid bone and has limited direct tongue protrusion, another depresses and retracts the tongue, and the last elevates the posterior part of the tongue and assists with swallowing. The genioglossus is specifically specialized for protrusion and is innervated by the hypoglossal nerve.