Omohyoid muscle
| Omohyoid muscle | |
|---|---|
 The omohyoid muscle, highlighted. | |
 Muscles of the neck. Anterior view. Omohyoid is labeled on both sides. | |
| Details | |
| Origin | Upper border of the scapula (inferior belly), intermediate tendon (superior belly) |
| Insertion | Intermediate tendon (inferior belly), hyoid bone (superior belly) |
| Artery | Branches from the inferior thyroid artery (ITA) |
| Nerve | Ansa cervicalis (C1-C3) |
| Actions | Depresses the larynx and hyoid bone. Also carries hyoid bone backward and to the side. |
| Identifiers | |
| Latin | musculus omohyoideus |
| TA98 | Lua error in Module:Wikidata at line 746: attempt to index field 'wikibase' (a nil value). |
| TH | {{#property:P1694}} |
| TE | {{#property:P1693}} |
| FMA | {{#property:P1402}} |
| Anatomical terms of muscle [[[d:Lua error in Module:Wikidata at line 865: attempt to index field 'wikibase' (a nil value).|edit on Wikidata]]] | |
The omohyoid muscle is a muscle in the neck. It is one of the infrahyoid muscles. It consists of two bellies separated by an intermediate tendon. Its inferior belly is attached to the scapula; its superior belly is attached to the hyoid bone. Its intermediate tendon is anchored to the clavicle and first rib by a fascial sling. The omohyoid is innervated by the ansa cervicalis of the cervical plexus. It acts to depress the hyoid bone.
Anatomy
[edit | edit source]Structure
[edit | edit source]The omohyoid muscle consists of muscle bellies that meet at an angle at the muscle's intermediate tendon.[1]
Inferior belly
[edit | edit source]The inferior belly is narrow and flat band.[1]
It arises from the superior border of scapula (near the scapular notch). It sometimes also arises from the superior transverse scapular ligament.[1]
It is directed anteriorly and somewhat superiorly from its origin, extending across the inferior portion of the neck. It passes posterior to the sternocleidomastoid muscle to insert at the intermediate tendon.[1]
Superior belly
[edit | edit source]The superior belly arises at the intermediate tendon. It extends nearly vertically superior-ward close to the lateral border of sternocleidomastoid muscle to insert at the inferior border of the body of hyoid bone (its site of insertion is lateral to that of the sternohyoid muscle).[1]
Intermediate tendon
[edit | edit source]The intermediate tendon is variable in length and form, and contains a variable amount of muscle tissue. It is anchored inferiorly to the clavicle and first rib by a band of deep cervical fascia that surrounds the intermediate tendon; this fascial fixation maintains the angle of the muscle.[1]
It is typically situated at the level of the arch of cricoid cartilage, adjacent to the internal jugular vein.[1]
Innervation
[edit | edit source]The omohyoid is innervated by the ansa cervicalis of the cervical plexus.[2] The inferior belly is innervated by the ansa cervicalis itself (which is derived from cervical spinal nerves C1-C3), and the superior belly is innervated by the superior root of ansa cervicalis (which is derived from the first cervical spinal nerve (C1)).[1]
Relations
[edit | edit source]The inferior belly of the omohyoid divides the posterior triangle of the neck into a occipital triangle (above) and a subclavian triangle (below).[3][verification needed]
Its superior belly divides the anterior triangle into an carotid triangle (above) and a muscular triangle (below).[3][4][verification needed] Its superior belly serves as the most lateral member of the infrahyoid muscles, located lateral to both the sternothyroid muscles and the thyrohyoid muscles.[5][verification needed]
The tendon is related to the internal jugular vein and can be used as a landmark for this vein during surgery.[citation needed]
Variation
[edit | edit source]The omohyoid muscle may be doubled or completely absent in some people.[citation needed] Either belly may be doubled or absent.[6]
The inferior belly may be attached to the clavicle directly (rather than by fascia).[7]
The superior belly may be fused with the sternohyoid muscle.[8]
Actions/movements
[edit | edit source]The muscle depresses the hyoid bone when the bone is in an elevated position.[1]
A putative action of the muscle is tension of the inferior portion of deep cervical fascia to prevent soft tissues from collapsing inward into the upper airway during deep inspiration.[1]
Etymology
[edit | edit source]The name "omohyoid" derives from the Greek "omos" meaning shoulder, giving one of its attachments, and "hyoid", giving the other attachment – the hyoid bone.[citation needed]
See also
[edit | edit source]References
[edit | edit source]Public domain This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)
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- ^ Human anatomy, Jacobs, Elsevier, 2008, page 189
- ^ Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, page 102
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External links
[edit | edit source]
- Anatomy photo:24:06-0100 at the SUNY Downstate Medical Center
- Anatomy figure: 24:01-09 at Human Anatomy Online, SUNY Downstate Medical Center
- lesson6 at The Anatomy Lesson by Wesley Norman (Georgetown University)
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