Anterior neck muscles

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Overview of the muscles that define the anterior neck.

The anterior neck muscles are a group of muscles located on the anterior aspect of the neck. They can be further subdivided into 5 groups: superficial, scalene, suprahyoid, infrahyoid and anterior vertebral (prevertebral) muscles.

The superficial muscles, as the name suggests, are the most superficial of the groups and include the platysma and sternocleidomastoid. The platysma lowers the mandible and tenses the skin of the lower neck and face. The sternocleidomastoid laterally flexes the neck and contralaterally rotates the head if contracting unilaterally, while it can extend the lower cervical spine and flex the upper cervical spine if contracting bilaterally, as well as elevating the sternum and clavicles if the head is fixed in place. 

The scalene group is comprised of three muscles known as the anterior, middle and posterior scalene muscles. The primary functions of this group are to flex the neck if contracting bilaterally, or laterally flex and contralaterally rotate the neck if contracting unilaterally. They can also elevate the first two ribs if the neck is fixed in place. 

The suprahyoid and infrahyoid groups are named according to their position relative to the hyoid bone. The suprahyoid muscles are located superior to the hyoid bone and include the stylohyoid, mylohyoid, geniohyoid and digastric. They function primarily to elevate the hyoid bone or depress the mandible if the hyoid is fixed in place. The infrahyoid muscles conversely are located inferior to the hyoid bone and include the sternohyoid, sternothyroid, thyrohyoid and omohyoid. They function primarily to depress the hyoid bone. 

The anterior vertebral muscles, also known as the prevertebral muscles, are the deepest group, found immediately anterior to the cervical vertebrae and are surrounded by the prevertebral fascia of the neck. The muscles in this group are the rectus capitis anterior, rectus capitis lateralis, longus capitis and longus colli. They primarily function to flex the head and neck if contracting bilaterally or laterally flex and rotate the head and neck if contracting unilaterally.