The infrahyoid muscles, or strap muscles, are a group of four pairs of

muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

s in the

anterior Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

(frontal) part of the

neck The neck is the part of the body in many vertebrates that connects the head to the torso. It supports the weight of the head and protects the nerves that transmit sensory and motor information between the brain and the rest of the body. Addition ...

. The four infrahyoid muscles are the sternohyoid, sternothyroid, thyrohyoid and omohyoid muscles. Excluding the sternothyroid, the infrahyoid muscles either originate from or insert on to the hyoid bone. The term ''infrahyoid'' refers to the region below the

hyoid bone The hyoid-bone (lingual-bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid-cartilage. At rest, it lies between the base of the mandible and the third cervical verte ...

, while the term strap muscles refers to the long and flat muscle shapes which resembles a

strap A strap, sometimes also called strop, is an elongated flap or ribbon, usually of leather or other flexible materials. Thin straps are used as part of clothing or baggage, or bedding such as a sleeping bag. See for example spaghetti strap, s ...

. The stylopharyngeus muscle is considered by many to be one of the strap muscles, but is not an infrahyoid muscle.

Individual muscles

The origin, insertion and innervation of the individual muscles:

Nerve supply

All of the infrahyoid muscles are innervated by the ansa cervicalis from the

cervical plexus The cervical plexus is a nerve plexus of the anterior rami of the first (i.e. upper-most) four cervical spinal nerves C1-C4. The cervical plexus provides motor innervation to some muscles of the neck, and the diaphragm; it provides sensory inne ...

( C1- C3) except the thyrohyoid muscle, which is innervated by fibers only from the first cervical spinal nerve travelling with the

hypoglossal nerve The hypoglossal nerve, also known as the twelfth cranial nerve, cranial nerve XII, or simply CN XII, is a cranial nerve that innervates all the extrinsic and intrinsic muscles of the tongue except for the palatoglossus, which is innervated b ...

Function

The infrahyoid muscles function to elevate and depress the hyoid bone and

larynx The larynx (), commonly called the voice box, is an organ (anatomy), organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal ...

during

swallowing Swallowing, also called deglutition or inglutition in scientific and medical contexts, is a physical process of an animal's digestive tract (e.g. that of a human body) that allows for an ingested substance (typically food) to pass from the mou ...

and speech. This moves the larynx as one unit.

References

{{DEFAULTSORT:Infrahyoid Muscles Muscles of the head and neck

Individual muscles

Nerve supply

Function

See also

References