Let’s examine the omohyoid muscle. Omohyoid, or omohyoideus, is a muscle with two bellies.
The inferior belly originates from the superior border of the scapula and runs from posterior to anterior across the superior shoulder toward the clavicle.
The central tendon of omohyoid (i.e., the tendon between the inferior and superior bellies) is attached to the clavicle by a fibrous expansion of the cervical fascia.
This attachment changes the direction of the muscle moving the superior belly distal toward the hyoid bone, where the superior belly inserts.
The action of omohyoid is to depress the hyoid bone.
These are the most common stats for omohyoid, but variations of the muscle are common.
The origin site at the superior border of the scapula can vary in location and in size, and at times the muscle also originates from the superior transverse scapular ligament.
The attachment of the central tendon can be only to the clavicle or to the clavicle and the first rib.
At its insertion site on the inferior hyoid, the omohyoid superior belly may be individuated or may have blended with the sternohyoid muscle.
Additional anomalies include a missing inferior belly, a double omohyoid, the superior belly may receive additional muscular slips from the manubrium.
Variations in the muscle are present in approximately 20% of people.
Functionally knowledge about omohyoid is important because of how many structures this one muscle ties together.
Omohyoid is a muscular connection between the upper shoulder and the anterior neck.
Muscular tension in the shoulder that causes the shoulder to elevate may cause a shift in the hyoid bone.
Muscle attachments on the superior border of the hyoid bone include mylohyoid and geniohyoid, which also attach to the mandible.
A shift in the hyoid has the potential to create a shift in the mandible.
It may also be that greater muscle tension in one temporomandibular joint causes a shift in the mandible, which leads to a shift in the hyoid bone, which leads to tension in omohyoid, which contributes to scapular elevation.
It is also possible that tension in omohyoid can contribute to decreased space between the scapula and clavicle in the superior shoulder, which could contribute to thoracic outlet symptoms.
Omohyoid – an important muscle to understand and to be able to release.
We release this muscle in both the SMRT: Head & Neck course (final 2014 live class August 1st and 2nd in Sandy Springs, GA) and in the SMRT: Shoulder, Axilla, Ribcage, & Upper Back course (final 2014 live class September 5th through 7th in Chapel Hill, NC).
For more information, https://efullcircle.com/class-schedule/