Cleido-occipital platysma muscle: a rare variant of sternocleidomastoid muscle

Additional and abnormal muscles are not an uncommon in the head and neck region. A supernumerary muscle bundle from the cleido-mastoid part of sternocleidomastoid muscle was encountered during routine dissection of the head and neck region of a 60-year-old female cadaver. The supernumerary muscle bundle was merging with the fibers of platysma muscle. The description of such a muscle in the modern literature is vague and we named the abnormal muscle bundle as cleido-occipital platysma muscle. The clinical and embryological significance of the variation is discussed