Entrapment of Suprascapular Artery between Split Parts of Right Inferior Belly of Omohyoid Muscle - A Rare Case Report

Abstract

Inferior belly of omohyoid is used as a landmark for endoscopic exploration of the brachial plexus. Variation of inferior belly of omohyoid muscle has immense clinical significance because of its relation to brachial plexus, external jugular vein, suprascapular nerve, vessels and phrenic nerve. The need to understand muscular variation is of greater importance because of the increased number of endoscopic surgeries and images for diagnosis. A number of variations of omohyoid muscle such as the absence of muscle, unusual sites of origin and insertion, and multiple bellies have been reported. Doubling or splitting of superior belly of the omohyoid has been reported several times. However, the splitting of the inferior belly of the omohyoid muscle is rarely reported. Herein we report a case of unusual splitting of inferior belly of omohyoid muscle. During the dissection for undergraduate students at AIIMS Bhubaneswar, unusual morphology of inferior belly of omohyoid muscle was observed in formalin embalmed 60-year-old male cadaver. The inferior belly of omohyoid was split. Another important finding observed was suprascapular artery entrapment between the split upper and lower parts of belly of inferior omohyoid with slight indentation mark on the artery suggestive of chronic compression. This muscle is used for various important clinical procedures and is an important landmark for radical neck dissection. So, the knowledge of possible anomalies of omohyoid is important.

Keywords

• Brachial plexus
• Supraclavicular block
• Supraclavicular triangle