Mylohyoid muscle: the floor of the mouth

The mylohyoid is a flat, thin muscle that forms the floor of the mouth. Its fibers start from the inner surface of the mandible (the mylohyoid line) and run to a median raphe and to the hyoid bone, so that the two sides together form a kind of "sling" that supports the tongue and the contents of the floor of the mouth. It is part of the suprahyoid group.

What is its function?

The mylohyoid raises the floor of the mouth and the tongue during swallowing, and helps the hyoid rise. When the hyoid is fixed, it contributes to opening the mouth, together with the digastric muscle. It is a muscle with a discreet action, but essential to the mechanics of swallowing.

Where does it sit relative to the layers of the neck?

Following the layers of the submental region, from the surface to the depth:

1. skin;
2. subcutaneous fat and submental fat;
3. platysma;
4. subplatysmal fat and structures such as the submandibular gland;
5. digastric bellies and the mylohyoid, which form the deep muscular plane.

This order matters for the reasoning: a visible double chin usually involves the superficial layers, but the deep plane provides the "floor" on which everything rests.

Why does it matter in facial harmonization?

Four practical reasons:

• Reading the double chin: distinguishing what is fat, skin, platysma and deep structure avoids blaming everything on fat (see double chin).
• Cervicomental angle: the position of the hyoid and the tension of the deep muscles influence the contour between the chin and the neck (see cervicomental angle).
• Procedure depth: the mylohyoid is a deep boundary of the submental region. Procedures such as enzymatic lipolysis or injections in the area require knowledge of the plane and the structures that accompany it.
• Functional symptoms: dysphagia and pain in the floor of the mouth are not aesthetic complaints.

How do you explain it to the patient?

Patients often think that a "double chin" is just fat. A layered explanation helps set expectations and shows why some cases do not respond to a single treatment.

In Harmy

The Chin point and the Jawline simulate volume in areas visible from the front. The app does not represent the deep submental region or muscles. The projection is illustrative and the assessment of the neck layers is clinical.

Also called: diaphragm of the mouth, oral muscular floor.