The short head arises by a thick flattened tendon from the apex of the coracoid process, in common with the Coracobrachialis. The long head arises from the supraglenoid tuberosity at the upper margin of the glenoid cavity, and is continuous with the glenoidal labrum. It is inserted into the rough posterior portion of the tuberosity of the radius, a bursa being interposed between the tendon and the front part of the tuberosity. As the tendon of the muscle approaches the radius it is twisted upon itself, so that its anterior surface becomes lateral and is applied to the tuberosity of the radius at its insertion. Opposite the bend of the elbow the tendon gives off, from its medial side, a broad aponeurosis, the lacertus fibrosus (bicipital Fascia) that passes obliquely downward and medial ward across the Brachial artery, and is continuous with the deep Fascia covering the origins of the Flexor muscles of the forearm The Biceps brachii (Biceps; Biceps flexor cubiti is a long fusiform muscle, placed on the front of the arm, and arising by two heads, from which circumstance it has received its name. Blood Supply Axillary Artery Nerve Supply The musculocutaneous nerve supplies it.

The Biceps brachii is a flexor of the elbow and, to a less extent, of the shoulder; it is also a powerful supinator, and serves to render tense the deep Fascia of the forearm by means of the lacertus fibrosus given off from its tendon.