Mylohyoid
Neck · Head & Neck
The mylohyoid is a flat, triangular suprahyoid muscle that forms the muscular floor of the mouth, spanning between the two halves of the mandible. It arises from the mylohyoid line on the inner surface of the mandible and passes medially to insert on the body of the hyoid bone and a median fibrous raphe where it meets its fellow of the opposite side. The paired muscles form a sling that elevates the hyoid bone and the floor of the mouth during swallowing and speech, and they can also help depress the mandible. It is supplied by the mylohyoid nerve, a branch of the inferior alveolar nerve from the mandibular division of the trigeminal nerve (CN V3).
Origin, Insertion, Action & Nerve
Origin
Mylohyoid line of mandible
Insertion
Body of hyoid bone and median fibrous raphe
Action
Elevates hyoid bone and floor of mouth; depresses mandible
Nerve
Mylohyoid nerve (branch of inferior alveolar nerve, CN V3)
Attachments explained
The Mylohyoid 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
Mylohyoid line of mandible
Insertion
Body of hyoid bone and median fibrous raphe
Action & function
When the Mylohyoid contracts, it produces the following movements: Elevates hyoid bone and floor of mouth; depresses mandible.
As part of the Neck 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 Mylohyoid receives its nerve supply from the Mylohyoid nerve (branch of inferior alveolar nerve, CN V3).
Because a muscle can only contract when its nerve is intact, injury to the Mylohyoid nerve can weaken or paralyse the Mylohyoid, impairing the movements it normally produces (elevates hyoid bone and floor of mouth). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Mylohyoid (the OIANS method)
Picture the mylohyoid as the hammock that makes up the floor of the mouth, its two halves meeting at a midline raphe between the mandible and the hyoid. Because it forms this sheet, its main job is to lift the floor of the mouth and the hyoid during swallowing, pushing the tongue upward against the palate; imagining that upward heave of the mouth floor fixes the action.
Tie the nerve to its neighbour the anterior belly of digastric, which shares the same mylohyoid nerve from the mandibular division of the trigeminal nerve (CN V3). Grouping these floor-of-mouth muscles under one trigeminal branch avoids confusing them with facial-nerve muscles, and its mylohyoid line origin conveniently echoes the muscle's own name.
Frequently asked questions
Where is the Mylohyoid located?
The Mylohyoid is a muscle of the Neck group, located in the Head & Neck.
What is the origin of the Mylohyoid?
Mylohyoid line of mandible
What is the insertion of the Mylohyoid?
Body of hyoid bone and median fibrous raphe
What movements does the Mylohyoid produce?
Elevates hyoid bone and floor of mouth; depresses mandible
What nerve supplies the Mylohyoid?
Mylohyoid nerve (branch of inferior alveolar nerve, CN V3)
Is the Mylohyoid free to study in OIANS?
The Mylohyoid 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
Study the Mylohyoid
Test yourself on Head & Neck muscles with interactive quizzes and flashcards in the free OIANS app.
Quiz yourself → Flashcards Open the OIANS app
Browsing is always free. A one-time Lifetime unlock adds every region's quizzes, flashcards, progress tracking and explore tools.