Biceps Brachii Location
Biceps brachii muscle is located in the front of the upper arm; it extends from the upper part of the shoulder blade (scapula) to the inside of the elbow.
- Long (outer) head: supraglenoid tubercle of the scapula 
- Short (inner) head: coracoid process of the scapula 
- Radial tuberosity and bicipital aponeurosis to the fascia on the medial side of the forearm 
- When the forearm is supine (palm-up), both heads flex the forearm in the elbow.
- Both heads supinate (turn palm-up) the forearm in the elbow.
- Both heads weakly flex (forwardly elevate) the arm in the shoulder.
- References: [1,2]
- Musculocutaneous nerve; spinal roots C5-C7 
- Brachial artery 
Video 1. Biceps brachii anatomy:
origin, insertion, actions, related muscles and ligaments,
arteries, nerve supply, rupture of tendons
Related anatomy: shoulder muscles
Upper Tendon of the Long (Outer) Biceps Brachii Head
The tendon of the long biceps head originates at the supraglenoid tubercle of the scapula and passes underneath the transverse humeral ligament in the bicipital groove between the lesser and greater tuberosity of the humerus (Video 1). In the bicipital groove, the tendon of the long biceps head lies beneath the tendon of the subscapularis muscle, which fixes the position of the bicipital tendon (Video 1).
Tendinitis (inflammation) or tendonitis (irritation) of the upper tendon of the long biceps head usually occurs in the bicipital groove.
In subscapularis tendon tear, the tendon of the long biceps head often dislocates out of its normal position.
A tear of the tendon of the long biceps brachii head due to an injury or overuse results in the movement of the biceps muscle down and therefore in the visible lump on the inside of the lower part of the upper arm near the elbow (Popeye sign or Popeye deformity) . A tendon tear can result from an injury or overuse .
Upper Tendon of the Short (Inner) Biceps Brachii Head
The tendon of the short biceps head originates at the coracoid process of the scapula. A tear of short biceps head is rare .
Lower (Distal) Tendon of the Biceps Brachii
The lower tendon of the biceps brachii muscle runs along the inside of the elbow and attaches to the upper part of the radius bone in the forearm. A tear of the distal biceps tendon is rare.
Biceps Brachii Pain
Biceps brachii tendon pain, which appears in the front of the shoulder, can be caused by overuse, impingement, dislocation, strain or rupture.
Biceps brachii muscle pain, which appears in the front of the upper arm, can be caused by a contusion or excessive training (delayed onset muscle soreness).
Biceps Brachii Strength Test
Raise an arm a bit and keep your hand by palm facing the floor. All at once, try to raise your upper arm in the shoulder, flex the forearm in the elbow and turn your palm up (Video 2).
The weakness of the biceps brachii–when compared to the opposite side–can speak for a muscle strain or tear or a nerve damage, for example, due to a herniated disc (C4-C5) that presses on the nerve root C5 in the neck spine (Video 1).
Video 2. Biceps brachii muscle strength test