15.8:
Muscles of the Anterior Neck
The anterior neck muscles are classified as suprahyoid and infrahyoid based on their position relative to the hyoid bone.
The suprahyoid muscles — the digastric, mylohyoid, geniohyoid, and stylohyoid — all insert into the hyoid bone.
The anterior belly of the paired digastric muscle originating from the mandible and the posterior belly originating at the temporal bone join at the intermediate tendon.
The flat and triangular mylohyoid and the paired geniohyoid muscles also originate from the mandible.
Lastly, the paired stylohyoid muscle arises from the styloid process of the temporal bone.
The infrahyoid muscles include the paired sternohyoid, omohyoid, sternothyroid, and thyrohyoid.
The sternohyoid muscle originates from the manubrium and the clavicle.
Originating near the suprascapular notch, the inferior belly of the omohyoid muscle inclines upwards, uniting with the superior belly via the central tendon.
The thyrohyoid arises from the thyroid cartilage and inserts onto the hyoid bone alongside the sternohyoid and omohyoid muscles.
Lastly, the sternothyroid originates from the manubrium and first costal cartilage and inserts into the thyroid cartilage.
15.8:
Muscles of the Anterior Neck
The anterior neck muscles are the group of muscles covering the front part of the neck. These muscles are classified into three subgroups. The first one is the superficial muscles, the most visible muscles in the front of the neck. It includes the platysma and sternocleidomastoid. The second group is the suprahyoid muscles, located above the hyoid bone. This group comprises the digastric, mylohyoid, geniohyoid, and stylohyoid. Lastly, the infrahyoid muscles are found below the hyoid bone and consist of the sternohyoid, omohyoid, sternothyroid, and thyrohyoid.
Superficial Muscles
The platysma is a broad, thin muscle stretching from the chest and shoulders to the lower jaw and face. It is located just under the skin, and it is one of the superficial muscles that form the expression of the neck. The sternocleidomastoid muscle, often abbreviated as SCM, is a prominent and easily visible muscle that runs along each side of the neck. As its name suggests, its attachment points are the sternum, clavicle, and mastoid process of the skull. This muscle is primarily responsible for rotating and flexing the head.
Suprahyoid Muscles
All the four suprahyoid muscles connect to the hyoid bone. The digastric muscle has two parts, one starting at the jaw and the other at the temporal bone, which joins at the intermediate tendon. The flat and triangular mylohyoid and the geniohyoid muscles start at the jaw. The stylohyoid muscle is paired and begins at the styloid process of the temporal bone.
Infrahyoid Muscles
The infrahyoid muscles comprise the sternohyoid, omohyoid, sternothyroid, and thyrohyoid. The sternohyoid muscle starts at the manubrium and the clavicle. The omohyoid muscle has two parts — the inferior belly originates near the suprascapular notch, inclining upwards and connecting with the superior belly via the central tendon. The thyrohyoid muscle begins at the thyroid cartilage and links to the hyoid bone alongside the sternohyoid and omohyoid muscles. Lastly, the sternothyroid muscle starts at the manubrium and first costal cartilage and connects to the thyroid cartilage.