The Infrahyoid muscles
They lie over
Consist of 4 muscles
- Thyrohyoid muscle
- Omohyoid muscle
- Sternohyoid muscle
Arranged into 2 layers
1-The superficial layer
2-The deep layer
The superficial layer
is a thin, narrow muscle attaching the hyoid bone to the sternum, serving to depress the hyoid bone. It is innervated by the ansa cervicalis.
The muscle arises from the posterior border of the medial end of the clavicle, the posterior sternoclavicular ligament, and the upper and posterior part of the manubrium sterni.Passing upward and medially, it is inserted by short tendinous fibers into the lower border of the body of the hyoid bone
Long, narrow 2 bellied muscle
Located on the anterolateral surface of the neck
Inferior belly originates from the upper horn of the hyoid
Prevents the neck region from collapsing during deep inspiration
Prevents blood vessels of the neck from being compressed
The deep layer
- back of manubrium: oblique line of thyroid cartilage
is a small, quadrilateral muscle appearing like an upward continuation of the Sternothyroid. It belongs to the infra-hyoid muscles group.
It arises from the oblique line on the lamina of the thyroid cartilage, and is inserted into the lower border of the greater cornu of the hyoid bone.