Genioglossus (Superior Fibers)
Tongue · Head & Neck
The superior fibres of the genioglossus are the uppermost part of the fan that arises from the superior genial tubercle (mental spine) of the mandible and fans out into the dorsum of the tongue and the body of the hyoid bone. These highest fibres reach toward the tip of the tongue, and when they contract they draw the apex backward and downward, retracting the tip. Together with the other parts of genioglossus they allow the tongue to be shaped and repositioned during chewing, swallowing, and articulation. Like almost all tongue muscles, the superior fibres are supplied by the hypoglossal nerve (CN XII).
Origin, Insertion, Action & Nerve
Origin
Superior genial tubercle (mental spine) of the mandible
Insertion
Dorsum of the tongue and body of the hyoid bone
Action
Draws the tip of the tongue back and down
Nerve
Hypoglossal nerve (CN XII)
Attachments explained
The Genioglossus (Superior Fibers) is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.
Origin
Superior genial tubercle (mental spine) of the mandible
Insertion
Dorsum of the tongue and body of the hyoid bone
Action & function
When the Genioglossus (Superior Fibers) contracts, it produces the following movement: Draws the tip of the tongue back and down.
As part of the Tongue group of the Head & Neck, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Genioglossus (Superior Fibers) receives its nerve supply from the Hypoglossal nerve (CN XII).
Because a muscle can only contract when its nerve is intact, injury to the Hypoglossal nerve can weaken or paralyse the Genioglossus (Superior Fibers), impairing the movements it normally produces (draws the tip of the tongue back and down). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Genioglossus (Superior Fibers) (the OIANS method)
Locate these fibres by their target: the superior band runs toward the apex, so it moves the tip. Remembering that the highest fibres pull the tip back and down distinguishes them cleanly from the inferior fibres that protrude the whole tongue and the middle fibres that depress its centre.
Consolidate the genioglossus as a single unit under one nerve. All three bands are driven by CN XII, so a lesion abolishes protrusion, central depression, and apex retraction together. Rehearsing the three actions in sequence while recalling the shared mental spine origin turns a set of similar entries into one coherent muscle.
Frequently asked questions
Where is the Genioglossus (Superior Fibers) located?
The Genioglossus (Superior Fibers) is a muscle of the Tongue group, located in the Head & Neck.
What is the origin of the Genioglossus (Superior Fibers)?
Superior genial tubercle (mental spine) of the mandible
What is the insertion of the Genioglossus (Superior Fibers)?
Dorsum of the tongue and body of the hyoid bone
What movements does the Genioglossus (Superior Fibers) produce?
Draws the tip of the tongue back and down
What nerve supplies the Genioglossus (Superior Fibers)?
Hypoglossal nerve (CN XII)
Is the Genioglossus (Superior Fibers) free to study in OIANS?
The Genioglossus (Superior Fibers) is always free to browse. Its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory. Quiz and Flashcard practice for the Head & Neck is part of the one-time Lifetime upgrade, though; only the Upper Limb decks are free to test yourself on.
Related muscles
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