The tongue is a complex muscle comprised of both intrinsic and extrinsic muscles working together. The extrinsic muscles originate outside the tongue and influence its position, while the intrinsic muscles are entirely within the tongue and alter its shape.
Extrinsic Tongue Muscles:
These muscles control the tongue's overall position and movement within the mouth. Key extrinsic muscles include:
- Genioglossus: This is the largest tongue muscle. It protrudes (sticks out) the tongue. Anatomy, Head and Neck, Tongue - StatPearls - NCBI Bookshelf
- Styloglossus: This muscle retracts (pulls back) the tongue and elevates its sides. Anatomy, Head and Neck, Tongue - StatPearls - NCBI Bookshelf
- Hyoglossus: This muscle retracts the tongue and depresses (pulls down) its sides. Anatomy, Head and Neck, Tongue - StatPearls - NCBI Bookshelf
- Palatoglossus: While often grouped with the extrinsic muscles, its function is more complex, contributing to both tongue and soft palate movement during swallowing.
Intrinsic Tongue Muscles:
These muscles, located within the tongue itself, modify its shape and allow for complex movements necessary for speech and swallowing. They include:
- Superior Longitudinal Muscle: Shortens the tongue and turns the tip upward.
- Inferior Longitudinal Muscle: Shortens the tongue and turns the tip downward.
- Transverse Muscle: Narrows and elongates the tongue.
- Vertical Muscle: Flattens and broadens the tongue.
Innervation:
The hypoglossal nerve (CN XII) innervates almost all the tongue muscles, both intrinsic and extrinsic, except for the palatoglossus, which is innervated by the vagus nerve (CN X). Neuroanatomy, Cranial Nerve 12 (Hypoglossal) - StatPearls - NCBI
