Cleido Occipitalis Cervicis: An anomalous muscle.

Abstract

An additional uncommon muscle fasciculus, Cleido Occipitalis Cervicis (COC) from the anterior border of the trapezius muscle was found during routine dissection. The variant muscle slip was separated from the trapezius muscle and was inserted on the posterior surface of medial two third of shaft of the clavicle as a separate tendon and forms the cleido occipitalis cervicis triangle in the neck. Remaining muscle fibers of trapezius inserted in to the clavicle and scapula as usual. The left external jugular vein was the content of the COC triangle. These variations of the trapezius muscle should be kept in mind during surgical operations or MR imaging observations of the