Muscle
Genioglossus
Fan-shaped muscle that advances the tongue
High-yield
One genioglossus pushes the tongue toward the opposite side. With a unilateral lower motor neuron lesion of CN XII, protrusion therefore usually points toward the weak side.
Overview
Genioglossus spreads from the inner front of the mandible into the tongue and toward the hyoid. Its broad fan of fibers helps move the tongue forward and reshape its central surface.
Reference facts
- Origin
- Superior mental spine on the inner surface of the mandibular symphysis
- Insertion
- Fibers spread through the tongue; the lowest fibers attach to the hyoid body
- Innervation
- Hypoglossal nerve (CN XII)
- Action
- Both sides advance the tongue and help depress its middle; one side moves it contralaterally
- Blood supply
- Sublingual branches of the lingual artery
Clinical correlation
Genioglossus activity contributes to upper-airway stability. Changes in its activation around sleep onset can reduce this support; airway obstruction depends on several anatomical and physiological factors.
Frequently asked questions
What does the genioglossus do?
Both sides advance the tongue and help depress its middle; one side moves it contralaterally.
What nerve innervates the genioglossus?
The genioglossus is innervated by the hypoglossal nerve (CN XII).
Where does the genioglossus attach?
Origin: Superior mental spine on the inner surface of the mandibular symphysis. Insertion: Fibers spread through the tongue; the lowest fibers attach to the hyoid body.
What is the blood supply of the genioglossus?
The genioglossus is supplied by the sublingual branches of the lingual artery.