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Middle Group of Neck Muscles

Musculi colli

For medical students2 min readUpdated 2026-10-10

The middle group of neck muscles is traditionally divided by anatomists into two main categories: suprahyoid and infrahyoid muscles. These muscular structures play a key role in the biomechanics of mandibular movements, the formation of the floor of the oral cavity, and the creation of vital topographic spaces that contain the internal organs of the neck.

ClassificationThe middle group includes suprahyoid and infrahyoid muscles

Median rapheServes as an attachment site for the m. mylohyoideus

Cervical pleuraReinforced by the scalenus minimus muscle

TriangleContains the thyroid gland, trachea, and larynx

Mylohyoid Muscle

This muscle (m. mylohyoideus) is one of the most important structures forming the muscular floor of the oral cavity.

Attachment Points:

Origin: Muscle fibers originate from the mylohyoid line located on the internal surface of the mandible.
Insertion: Fibers run toward the body of the hyoid bone and interweave into a specific tendinous structure — the median raphe (raphe mylohyoidea).

Biomechanics and Functions: The action of the muscle directly depends on which bone structure is fixed at a given moment:

When the hyoid bone is mobile, it pulls it upward while simultaneously elevating the floor of the oral cavity.
If the hyoid bone is firmly fixed by other muscles, contraction of the m. mylohyoideus leads to depression of the mandible.

Blood Supply and Innervation: Blood supply is provided by branches of the sublingual and submental arteries (aa. sublingualis, submentalis). Motor impulses are supplied by the mylohyoid nerve (n. mylohyoideus), which is a branch of the trigeminal nerve (n. trigeminus).

Scalenus Minimus Muscle

The scalenus minimus muscle (m. scalenus minimus) is an inconstant (variable) anatomical structure of the cervical region.

Its anatomical features include:

Origin: Muscle fibers originate from the transverse processes of the sixth and seventh cervical vertebrae (C6–C7).
Insertion: Fibers descend to reach the cupula of the pleura (cervical pleura) and the first rib.
Function: Due to its location and attachment points, this muscle performs an important task—it tensions and reinforces the cervical pleura, ensuring its stability.

Topographic Anatomy: Omotracheal Triangle

Special topographic zones are defined for precise orientation in the neck. One of these is the omotracheal, or muscular, triangle — trigonum omotracheale (musculare).

Boundaries of the Triangle:

Laterally, the space is limited by the anterior border of the sternocleidomastoid muscle (m. sternocleidomastoideus).
Superiorly and laterally, the boundary is formed by the inferior belly of the omohyoid muscle (m. omohyoideus).
Medially, the boundary is formed by the conventional midline of the neck.

Contents: Vital organs of the neck are projected within the omotracheal triangle. The thyroid gland, larynx, and cervical trachea are located here.

Mnemonic

To remember the function of the mylohyoid muscle, picture it as a "seesaw" between the mandible and the hyoid bone: if one end (the bone) is fixed, the other end (the mandible) moves down, and vice versa.

Frequently asked questions

Which muscles belong to the suprahyoid group of neck muscles?

The suprahyoid group includes muscles located above the hyoid bone that form the floor of the oral cavity. This group includes:

Mylohyoid muscle (m. mylohyoideus).
Geniohyoid muscle (m. geniohyoideus).
Digastric muscle (m. digastricus).
Stylohyoid muscle (m. stylohyoideus).

These muscles participate in mastication by depressing the mandible, and in swallowing by elevating the hyoid bone.

Which muscles form the infrahyoid group of neck muscles?

The infrahyoid group is formed by neck muscles located below the hyoid bone. These include:

Sternohyoid muscle (m. sternohyoideus).
Sternothyroid muscle (m. sternothyroideus).
Thyrohyoid muscle (m. thyrohyoideus).
Omohyoid muscle (m. omohyoideus).

These muscles fix the position of the hyoid bone and pull it downward, participating in swallowing. They can also function as accessory respiratory muscles.

Which neck muscles participate in the depression of the mandible?

The suprahyoid neck muscles participate in depressing the mandible (opening the mouth). These include:

Mylohyoid muscle (m. mylohyoideus) — depresses the mandible when the hyoid bone is fixed.
Digastric muscle (m. digastricus) — involves the anterior and posterior bellies.
Geniohyoid muscle (m. geniohyoideus).
Stylohyoid muscle (m. stylohyoideus).

An important biomechanical condition for their effective action is the rigid fixation of the hyoid bone by the musculature located below it.

What are the main groups of the middle neck musculature?

The middle group is classified into two main subgroups: suprahyoid and infrahyoid muscles.

To which bone does the mylohyoid muscle attach?

It attaches to the body of the hyoid bone, as well as to the median raphe (raphe mylohyoidea).

Where does the scalenus minimus muscle originate?

This variable muscle originates from the transverse processes of the lower cervical vertebrae, specifically C6 and C7.

What organs are located in the omotracheal triangle?

The thyroid gland, larynx, and trachea lie within this triangle (trigonum omotracheale).

Go deeper

Functional anatomy of other suprahyoid muscles
Complete composition of the infrahyoid muscle group
Variant anatomy of the cervical muscular system
Topography of all triangles of the anterior neck region