Between which structures are the infrahyoid muscles located?

They are located between the hyoid bone superiorly and the sternum, scapula, and thyroid cartilage inferiorly.

Which muscles form the superficial layer of this group?

The superficial layer includes the sternohyoid (m. sternohyoideus) and omohyoid (m. omohyoideus) muscles.

What is the function of the longus colli muscle?

It flexes the neck forward upon bilateral contraction and bends it laterally upon unilateral contraction.

Where do the parts of the longus colli muscle originate?

The superior oblique part originates from the bodies of C3–C5, the inferior oblique from the bodies of Th1–Th3, and the straight part from the bodies of C5–Th3.

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Infrahyoid Muscles

Musculi infrahyoidei

For medical students2 min readUpdated 2026-10-10

Infrahyoid muscles are an important anatomical group topographically located between the hyoid bone superiorly and the sternum, scapula, or thyroid cartilage inferiorly. Depending on their depth, these muscle bundles form two distinct layers that play a key role in the structural organization of the anterior neck.

Muscle layersThe entire infrahyoid group is clearly divided into superficial and deep anatomical layers.

AttachmentsThe muscles are stretched between the hyoid bone and the sternum, scapula, and thyroid cartilage.

Long muscleBelongs to the lateral group, consists of three parts, and is innervated by cervical nerves C2–C7.

General Topography and Layers of the Infrahyoid Muscles

Anatomically, infrahyoid muscles are located in the anterior region of the neck. Their superior attachment point is connected to the hyoid bone, while the inferior bundles extend to the sternum, scapula, and thyroid cartilage. The entire group is divided into two distinct layers: superficial and deep.

Superficial Layer

This layer includes two main muscles, whose names reflect their attachment points:

Sternohyoid muscle (m. sternohyoideus) — connects the sternum and the hyoid bone.
Omohyoid muscle (m. omohyoideus) — runs from the scapula to the hyoid bone.

Deep Layer

Deep to the superficial muscles lies the deep muscle layer. It is also represented by two structures:

Sternothyroid muscle (m. sternothyroideus) — fixed between the sternum and the thyroid cartilage.
Thyrohyoid muscle (m. thyrohyoideus) — located between the thyroid cartilage and the hyoid bone.

Lateral Group: Longus Colli Muscle

Special attention should be given to the lateral group, which includes the longus colli muscle (m. longus colli). This is a rather long anatomical structure structurally subdivided into three separate parts:

Pars obliqua superior (superior oblique part) — originates from the vertebral bodies of C3–C5 and courses upward to the atlas.
Pars obliqua inferior (inferior oblique part) — originates from the thoracic vertebral bodies of Th1–Th3 and attaches to the transverse processes of the cervical vertebrae C5–C6.
Pars recta (straight part) — extends vertically from the vertebral bodies of C5–Th3 to the bodies of the upper cervical vertebrae.

Functional Significance: Upon bilateral contraction, this muscle flexes the neck forward. When contracting unilaterally, it bends the neck to the corresponding side.

Blood Supply and Innervation:

Innervation: supplied by branches of the cervical spinal nerves — nn. cervicales (C2–C7).
Blood supply: provided by the vertebral arteries (aa. vertebrales) and deep cervical arteries (aa. cervicales profundae).

Mnemonic

To remember the infrahyoid group, note the logic of their Latin names: the first word always indicates the inferior attachment point (sterno- sternum, omo- scapula, thyro- thyroid cartilage), and the second indicates the superior one (-hyoideus — hyoid bone).

Frequently asked questions

Between which structures are the infrahyoid muscles located?: They are located between the hyoid bone superiorly and the sternum, scapula, and thyroid cartilage inferiorly.
Which muscles form the superficial layer of this group?: The superficial layer includes the sternohyoid (m. sternohyoideus) and omohyoid (m. omohyoideus) muscles.
What is the function of the longus colli muscle?: It flexes the neck forward upon bilateral contraction and bends it laterally upon unilateral contraction.
Where do the parts of the longus colli muscle originate?: The superior oblique part originates from the bodies of C3–C5, the inferior oblique from the bodies of Th1–Th3, and the straight part from the bodies of C5–Th3.

Go deeper

Detailed topography of the superficial layer and cervical fascia
Specifics of m. sternothyroideus attachment to the thyroid cartilage
Syntopy of m. longus colli parts with the vertebral column
Arterial network of the neck: branches of aa. vertebrales and cervicales profundae
Mechanism of unilateral and bilateral contraction of the lateral muscle group