Sternohyoid Muscle
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The sternohyoid muscle is a thin, narrow muscle attaching the hyoid bone to the
sternum The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Sh ...
. It is one of the paired
strap muscles The infrahyoid muscles, or strap muscles, are a group of four pairs of muscles in the anterior (frontal) part of the neck. The four infrahyoid muscles are the sternohyoid, sternothyroid, thyrohyoid and omohyoid muscles. Excluding the sternothyro ...
of the
infrahyoid muscles The infrahyoid muscles, or strap muscles, are a group of four pairs of muscles in the anterior (frontal) part of the neck. The four infrahyoid muscles are the sternohyoid, sternothyroid, thyrohyoid and omohyoid muscles. Excluding the sternothyro ...
. It is supplied by the
ansa cervicalis The ansa cervicalis (or ansa hypoglossi in older literature) is a loop of nerves that are part of the cervical plexus. It lies superficial to the internal jugular vein in the carotid triangle. Its name means "handle of the neck" in Latin. Bran ...
. It depresses the hyoid bone.


Structure

The sternohyoid muscle is one of the paired
strap muscles The infrahyoid muscles, or strap muscles, are a group of four pairs of muscles in the anterior (frontal) part of the neck. The four infrahyoid muscles are the sternohyoid, sternothyroid, thyrohyoid and omohyoid muscles. Excluding the sternothyro ...
of the
infrahyoid muscles The infrahyoid muscles, or strap muscles, are a group of four pairs of muscles in the anterior (frontal) part of the neck. The four infrahyoid muscles are the sternohyoid, sternothyroid, thyrohyoid and omohyoid muscles. Excluding the sternothyro ...
. It arises from the posterior border of the medial end of the
clavicle The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the r ...
, the
posterior sternoclavicular ligament The posterior sternoclavicular ligament is a band of fibers, covering the posterior surface of the sternoclavicular joint. It is attached above to the upper and back part of the sternal end of the clavicle, and, passing obliquely downward and med ...
, and the upper and posterior part of the manubrium of the
sternum The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Sh ...
. Passing upward and medially, it is inserted by short tendinous fibers into the lower border of the body of the hyoid bone. It runs lateral to the
trachea The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air- breathing animals with lungs. The trachea extends from the ...
.


Nerve supply

The sternohyoid muscle is supplied by a branch of the
ansa cervicalis The ansa cervicalis (or ansa hypoglossi in older literature) is a loop of nerves that are part of the cervical plexus. It lies superficial to the internal jugular vein in the carotid triangle. Its name means "handle of the neck" in Latin. Bran ...
.


Variations

The sternohyoid muscle may be doubled, have accessory slips (Cleidohyoideus) or be completely absent in some people. It sometimes presents a transverse tendinous inscription immediately above its origin.


Function

The sternohyoid muscle performs a number of functions: * depresses the hyoid bone. * helps with speech, primarily to do with
volume Volume is a measure of occupied three-dimensional space. It is often quantified numerically using SI derived units (such as the cubic metre and litre) or by various imperial or US customary units (such as the gallon, quart, cubic inch). Th ...
rather than intonation. * helps to move the head and neck.


Additional images

File:Gray116.png, Posterior surface of sternum. File:Gray201.png, Left clavicle. Inferior surface. File:Gray186.png, Hyoid bone. Anterior surface. Enlarged. File:Gray384.png, Section of the neck at about the level of the sixth cervical vertebra. File:Gray390.png, Posterior surface of sternum and costal cartilages, showing Transversus thoracis. File:Gray562.png, The fascia and middle thyroid veins. The veins here designated the inferior thyroid are called by Kocher the thyroidea ima. File:Anterior region of neck (9).JPG, Sternohyoid muscle File:Slide4cc.JPG, Sternohyoid muscle File:Slide3b.JPG, Sternohyoid muscle File:Slide5c.JPG, Sternohyoid muscle - lateral view File:Slide12d.JPG, Sternohyoid muscle - right view File:Slide1g.JPG, Sternohyoid muscle File:Slide2deded.JPG, Muscles, nerves and arteries of neck.Deep dissection. Anterior view.


References


External links

* - "Nerves and Vessels of the
Carotid triangle The carotid triangle (or superior carotid triangle) is a portion of the anterior triangle of the neck. Coverings and boundaries It is bounded: * Posteriorly by the anterior border of the Sternocleidomastoid; * Anteroinferiorly, by the superior bel ...
"
PTCentral
{{Authority control Muscles of the head and neck