Answer
Chewing and swallowing are aided by eight pairs of muscles associated with the hyoid bone. The four pairs located above the hyoid are the suprahyoid muscles; the infrahyoid group (also four pairs) is sited below the hyoid.
By name, the paired suprahyoid muscles are the digastric, the geniohyoid, the mylohyoid and the stylohyoid. The paired infrahyoids are the omohyoid, the sternohyoid, the thyrohyoid and the sternohyoid.
Work Step by Step
Functions of Suprahyoids:
Digastric : Depresses mandible when hyoid is fixed. . Opens mouth wide when ingesting food or yawning. elevates hyoid when mandible is fixed.
Geniohyoid: depresses mandible when hyoid is fixed; elevates and protracts hyoid when mandible is
fixed.
Mylohyoid: Forms floor of mouth: elevates floor of mouth in initial stage of swallowing.
Stylohyoid: elevates and retracts hyoid, elongating floor of mouth.
Functions of Infrahyoids:
Omohyoid: depresses hyoid after it has been elevated
Sternohyoid: depresses hyoid after it has been elevated.
Thyrohyoid: Depresses hyoid; with hyoid fixed , elevates larynx in singing high notes
Sternothyroid: depresses larynx after it has been elevated in swallowing and vocalization; ; aids in
singing low notes.
