A Study of Anatomical Variability of the Omohyoid Muscle and its Clinical Relevance

Abstract

Rai R, Ranade AV, Nayak SR, Vadgaonkar R, Pai MM, Krishnamurthy A. A study of anatomical variability of the omohyoid muscle and its clinical relevance. Clinics. 2008;63:521-4. OBJECTIVE:The omohyoid muscle is a long, thin muscle consisting of superior and inferior bellies and an intermediate tendon, which runs obliquely in the lateral cervical region. The omohyoid is important in neck dissections because it is the surgical landmark for level III and IV lymph node metastases. METHODS: In the present study, the anterior and posterior triangle of the neck was dissected in 35 male cadavers and observed for variations in the omohyoid bilaterally. Observations were focused on variations in number, attachments, and position of omohyoid. RESULTS: Among the 35 cadavers studied, double omohyoid was present in one cadaver, inferior belly originated from the clavicle in three cadavers, superior belly merged with the sternohyoid in two cadavers, and the omohyoid received additional slips from the sternum in one cadaver. Standard attachment and position of the omohyoid was observed in the remaining cadavers. CONCLUSION: Variations of this muscle are important because of its close relation to the large vessels and brachial plexus. Because of the direct adhesion of the intermediate tendon to the anterior wall of the internal jugular vein and its connection with it through a thin lamina of the pretracheal layer of the cervical fascia, the contraction of the omohyoid muscle has a direct effect on the lumen of this vessel.

Suprascapular Nerve Injury During Mohs Surgery and Review of the Surgical Anatomy of the Nervous Structures of the Supraclavicular Triangle

“…The SCF is a term used to describe the gross indentation just above the clavicle overlying the SCT. Multiple motor and sensory nerves of vital functional importance run within the SCT, although there is some variability of the anatomic location of the omohyoid muscle, which can lead to a marked inconsistency in the location of the nervous structures within the neck 2 . In addition to those structures of the SCT that will be discussed in further detail below, important structures of the posterior triangle encountered within the upper occipital triangle are the spinal accessory nerve and portions of the superficial cutaneous branches of the cervical plexus.…”

Internal Jugular Vein Compression Mitigates Traumatic Axonal Injury in a Rat Model by Reducing the Intracranial Slosh Effect

“…Finally, woodpeckers have a hyoid and omohyoid structure similar to that in humans. 18 Because of the direct proximity of the omohyoid atop the IJVs, it is intriguing to speculate that, on contraction of the omohyoid, perhaps with each peck, the IJVs may be partially occluded and intracranial compliance exhausted.…”

A unique muscle bridge between sternohyoid and sternothyroid muscles

“…In some studies, the fibers of sternohyoid and omohyoid are seen to fuse. [7,8] The omohyoid muscle is the most frequently absent amongst the infrahyoid group. Absence of one belly is more frequently observed than absence of bellies.…”

“…Sternohyoid and omohyoid fibers can also merge at the level of the hyoid bone on the upper part of the neck. [7] Nayak at al. [5] defined two-belly sternothyroids as lateral and medial.…”