The suprahyoid muscles are four

muscle Skeletal muscles (commonly referred to as muscles) are Organ (biology), organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other ...

s located above 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 verteb ...

in the

neck The neck is the part of the body on many vertebrates that connects the head with the torso. The neck supports the weight of the head and protects the nerves that carry sensory and motor information from the brain down to the rest of the body. In ...

. They are the digastric, stylohyoid, geniohyoid, and mylohyoid muscles. They are all

pharyngeal muscles The pharyngeal muscles are a group of muscles that form the pharynx, which is posterior to the oral cavity, determining the shape of its lumen, and affecting its sound properties as the primary resonating cavity. The pharyngeal muscles (involunta ...

, with the exception of the geniohyoid muscle. The digastric is uniquely named for its two bellies. Its posterior belly rises from the

mastoid process The mastoid part of the temporal bone is the posterior (back) part of the temporal bone, one of the bones of the skull. Its rough surface gives attachment to various muscles (via tendons) and it has openings for blood vessels. From its borders, t ...

of the

cranium The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, ...

and slopes downward and forward. The anterior belly arises from the

digastric fossa The mastoid part of the temporal bone is the posterior (back) part of the temporal bone, one of the bones of the skull. Its rough surface gives attachment to various muscles (via tendons) and it has Foramen, openings for blood vessels. From its bo ...

on the inner surface of the mandibular body, which slopes downward and backward. The two bellies connect at the intermediate tendon. The intermediate tendon passes through a connective tissue loop attached to the hyoid bone. The mylohyoid muscles are thin, flat muscles that form a sling inferior to the tongue supporting the floor of the mouth. The geniohyoids are short, narrow muscles that contact each other in the midline. The stylohyoids are long, thin muscles that are nearly parallel with the posterior belly of the digastric muscle.

Function

These four muscles have different actions, but in general assist in elevating the

and widening the

esophagus The esophagus (American English) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the ...

during

swallowing Swallowing, sometimes called deglutition in scientific contexts, is the process in the human or animal body that allows for a substance to pass from the mouth, to the pharynx, and into the esophagus, while shutting the epiglottis. Swallowing ...

. When the two bellies of the digastric contract, they pull upward on the hyoid bone; but if the hyoid is fixed from below, the digastric assists in extreme opening of the mouth such as yawning or taking a large bite of an apple. The mylohyoid elevates the hyoid bone, tenses the floor of the mouth. The Geniohyoid pulls the hyoid bone anterosuperiorly, shortening the floor of the mouth and widening the pharynx during swallowing. The Stylohyoid elevates and retracts the hyoid bone, elongating the floor of the mouth during swallowing.

References

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

Function

See also

References