Clinico-embryological perspective of a rare accessory brachial muscle with possible musculocutaneous nerve compression.
Both brachialis and biceps brachii are primary flexors of the arm and elbow from the biomechanical perspective. Numerous reports exist in anatomical literature regarding accessory heads of biceps brachii, although such accessory bellies in relation to brachialis muscle are less frequently elucidated. We report a unilateral case of a rare accessory muscle interposed between the biceps brachii and brachialis, having the musculocutaneous nerve (MCN) entrapped between the two. Furthermore, the muscle divided into two slips, upper slip was attached to biceps brachii and the other gained insertion to the brachial fascia. Innervation to this accessory muscle was derived from MCN. The embryological basis for such supernumerary muscle is discussed. Additionally, the case is considered under surgical and clinical perspective, highlighting the importance of familiarity with such variations. Anatomical variations of the brachial musculature may cause diagnostic perplexities while interpreting MRI or CT scans.
Department of anatomy, VMMC & Safdarjung Hospital, New Delhi, India. drvandanamehta@gmail.com
V
V
Mehta
Y
Y
Yadav
Jyoti
J
Arora
H
H
Kumar
R K
RK
Suri
G
G
Rath
D001132:Arm / Q000196:embryology; D002102:Cadaver; D006801:Humans; D018482:Muscle, Skeletal / Q000002:abnormalities* / Q000196:embryology; D009138:Musculocutaneous Nerve / Q000473:pathology*; D009408:Nerve Compression Syndromes / Q000473:pathology*