An Unusual Variation of Deltoid Muscle

An unusual anatomic variation of the deltoid muscle was found in a 45-year-old female cadaver during dissection of the right upper extremity. The posterior fibers of the right deltoid muscle were enclosed in a distinct fascial sheet and the deltoid muscle was seen to arise from the middle 1/3 of the medial border of the scapula. There was no accompanying vascular or neural anomaly of the deltoid muscle. To the best of our knowledge; unilateral posterior separation of the deltoid muscle with a distinct fascia has not been described previously. While dissecting deltoid; posterior deltoid; or scapular flaps; the surgeon needs to look out for this variation because it may cause confusion