Clinical implications of the cleido‐occipitalis cervicalis muscle: A muscular variant of the trapezius muscle

Abstract

Anatomical variation in the supraclavicular region is unusual, aside from the scalene muscles. This report presents a left‐sided cleido‐occipitalis cervicalis muscle found during routine dissection of an 87 year‐old female body donor. The variant muscle traveled from the occipital bone as part of the trapezius muscle, before deviating from the trapezius to descend inferiorly in the neck to insert into the superior and posterior aspect of the middle of the clavicle. As it traveled inferiorly towards the clavicle, the variant muscle passed immediately superficial to the transverse cervical artery. The muscle was innervated by the accessory nerve (or CN XI). With regard to clinical relevancy during imaging and physical examination, the cleido‐occipitalis cervicalis muscle may appear to be an arterial aneurysm, thrombosed vein, lymphovenous malformation, neck cyst, tumor, enlarged lymph node, or other soft tissue pathology. Within the literature, it has been reported that it may be difficult to distinguish the cleido‐occipitalis cervicalis muscle from the levator claviculae muscle, which is a more common muscular variant within the lateral cervical triangle. Furthermore, the presence of the cleido‐occipitalis cervicalis may present difficulty in the management of clavicular fractures— the most common type of bone fracture.Support or Funding InformationWVU Initiation to Research Opportunities (INTRO) ProgramThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.