Infrahyoid muscles

The infrahyoid muscles or strap muscles are a group of four paired muscles in the anterior neck below the hyoid bone, within the muscular triangle. They are responsible for depressing the hyoid during swallowing.

Gross anatomy

There are four strap muscles:

• sternohyoid: superficial and medial
• omohyoid: superficial and lateral
• sternothyroid: deep and medial
• thyrohyoid: deep and lateral

The strap muscles are ensheathed by the middle layer of the deep cervical fascia, thereby forming one of the deep fascial compartments of the neck, although it is not commonly recognized as such .

Innervation

Each muscle is supplied by different nerves from the ansa cervicalis.

History and etymology

The name "strap muscles" comes from their long and flat shape, similar to a belt or strap .

Clinical importance

The muscles are retracted apart in the midline to access the thyroid gland for thyroidectomy.