Suprahyoid and infrahyoid muscles: neck anatomy
Quick facts
- Definition
- Two groups of neck muscles, above and below the hyoid bone.
- Suprahyoid
- Digastric, mylohyoid, geniohyoid and stylohyoid.
- Infrahyoid
- Sternohyoid, sternothyroid, thyrohyoid and omohyoid.
- Relevance in HOF
- They determine the position of the hyoid and the deep contour of the neck.
The suprahyoid and infrahyoid muscles form two groups in the neck, organized around the hyoid bone, a horseshoe-shaped bone suspended in the front of the neck that does not articulate with any other bone. The hyoid works as a "mobile platform" that supports the tongue and takes part in swallowing and speech.
Which muscles make up each group?
| Group | Position | Muscles |
|---|---|---|
| Suprahyoid | Between the mandible and the hyoid | Digastric, mylohyoid, geniohyoid, stylohyoid |
| Infrahyoid | Between the hyoid and the chest | Sternohyoid, sternothyroid, thyrohyoid, omohyoid |
The suprahyoids raise the hyoid and lower the mandible when the hyoid is fixed. The infrahyoids lower the hyoid and the larynx, acting as antagonists of the first group. Together they balance the position of the bone, which is essential in chewing, swallowing and phonation.
What is the relationship with neck aesthetics?
The contour between the chin and the neck is not only a matter of fat and skin. Underneath, the position of the hyoid, the tension of the suprahyoid muscles and the length of the neck are part of the design of the cervicomental angle. A lower hyoid, for example, favors a more obtuse angle, and that is anatomical, not necessarily treatable with a procedure.
The visible double chin is a sum of layers: skin, submental fat, platysma and deep structures. When the professional understands this sum, they can tell the patient what can improve, what depends on surgery and what is an anatomical limit.
When does deep anatomy limit the result?
Some patients have a poorly defined cervicomental angle because of a low hyoid, a short neck or a small mandible. In these cases, neither fat reduction nor skin tightening will produce a sharp angle. It is essential to say this beforehand, so as not to promise what the anatomy does not allow.
In Harmy
The app does not represent the neck or deep muscles. The Chin and Jawline points simulate volume in areas visible from the front, with the volume in ml entered, as an illustrative simulation. Neck assessment is clinical.
Also called: hyoid muscles, anterior neck muscles.
Frequently asked questions
Do these muscles influence the angle between the chin and the neck?
They influence the position of the hyoid bone, which is part of the skeleton of the cervicomental contour. The deep anatomy, together with fat and skin, defines the angle seen from outside.