The most frequent sites of long head of the biceps rupture are at the origin and at the exit of the bicipital groove at the musculotendinous junction.
Loss of the superior attachment of the biceps causes the biceps to bunch distally causing a “Popeyes deformity”.
Origin of the short head of the biceps is at the coracoid process of the scapula.
The long head originates from the supraglenoid tubercle just below the shoulder joint, from where its tendon passes up along the intertubercular groove of the humerus into the joint capsule of the shoulder joint.
Its insertion into the radial tuberosity and the bicipital aponeurosis enters into deep fascia on medial part of forearm.
Blood supply is by the brachial artery and it is innervated by the musculocutaneous nerve from C5–C6.
The biceps flexes the elbow and supinates the forearm.
A two-headed muscle that lies on the upper arm between the shoulder and the elbow.
Both heads arise on the scapula and join to form a single muscle belly which is attached to the upper forearm.
The biceps crosses both the shoulder and elbow.
The tendon of the long head is held in place in the inter tubercular groove by the greater and lesser tubercles and the overlying transverse humeral ligament.
During motion from external to internal rotation, the tendon of the long head is forced medially against the lesser tubercle and superiorly against the transverse ligament.
The tendon of the short head runs adjacent to the coracobrachialis tendon and attaches to the coracoid process.
The long and short heads join at the middle of the humerus, near the insertion of the deltoid, to form a common muscle belly.
The biceps ends distally in two tendons: the stronger tendon inserts into the radial tuberosity on the radius, and the bicipital aponeurosis, radiates into the ulnar part of the antebrachial fascia.
The tendon that attaches to the radial tuberosity is surrounded by the bicipitoradial bursa, which ensures frictionless motion between the biceps tendon and the proximal radius during pronation and supination of the forearm.
Two muscles lie underneath the biceps brachii: the coracobrachialis muscle,that attaches to the coracoid process and the brachialis muscle which connects to the ulna and along the mid-shaft of the humerus.
The brachioradialis muscle is adjacent to the biceps and also inserts on the radius bone distally.
The biceps brachii is a variable muscle of the human body and has a third head arising from the humerus in 10% of cases.
The third head of the biceps most commonly originates near the insertion of the coracobrachialis and joins the short head.
Multiple supernumerary heads have been reported in rare cases.
The distal biceps tendons are completely separated in 40% and bifurcated in 25% of cases.
Biceps brachii is innervated by the musculocutaneous nerve together with coracobrachialis and brachialis nerves from fibers of the fifth and sixth cervical nerves.
The biceps is tri-articulate, working across three joints.
The most important of these functions is to supinate the forearm and flex the elbow.
The biceps brachii functions primarily as a powerful supinator of the forearm, turning the palm upwards.
This action, which is aided by the supinator muscle, requires the elbow to be at least partially flexed.
When the elbow, or humeroulnar joint, is fully extended, supination is then primarily carried out by the supinator muscle.
The biceps brachii is an important flexor of the forearm, particularly when the forearm is supinated.
When the forearm is in pronation the brachialis, brachioradialis, and supinator flex the forearm, with minimal contribution from the biceps brachii.
The biceps brachii weakly assists in forward flexion of the shoulder joint, that is bringing the arm forward and upwards, and may contribute to abduction of the arm to the side when the arm is externally, or laterally, rotated.
The short head of the biceps brachii also assists with horizontal adduction, that is the bringing the arm across the body when the arm is internally or medially rotated.
The short head of the biceps brachii is attached to the scapula and assists with stabilization of the shoulder joint.
The biceps muscle can be strengthened using weight and resistance training.
The long head is the outer portion of the muscle, while short head is the inner portion of the muscle.
When the elbows are pulled back behind the body, the long head is activated.
To target the short head for strengthening the elbows should be in front of the body.
Pathologic processes involving the proximal tendons of the biceps brachii are a frequent cause of anterior shoulder pain.
Disorders of the distal biceps brachii tendon are usually the result of a partial or complete tear of the muscle.
Partial tears demonstrate enlargement and abnormal contour of the tendon, while complete tears create a soft-tissue mass in the anterior aspect of the arm, the so called Popeye sign.
Complete tears of the distal biceps paradoxically leads to a decreased strength during flexion and supination of the forearm.
Tears of the biceps brachii occur with athletic activities.
Corrective surgery repairs biceps brachii tendon tears.
Proximal ruptures of the long head of the biceps tendon can be surgically repaired by tenodesis, the resurfacing of the tendon by screw fixation on the humerus and biceps tenotomy, the trimming the long head of the biceps tendon promoting the muscle origination from the coracoid process.
The most common symptom of a biceps tear is pain in the muscle, but may involve the shoulders and elbows.
Treatment of a biceps tear depends on the severity of the injury, with most cases the muscle heals with no corrective surgery.
The long head of the biceps rupture is responsible for 96% of all biceps brachii insults.
The long head of the biceps rupture occurs most commonly in individuals over the age of 50 years.
The long head of the biceps rupture is usually transverse.
Loss of function with long head rupture is slight weakness on supination.
Treatment of long head of the biceps rupture is conservative.
Surgical repair is considered in young patients for cosmesis, when supination at full strength is required or when surgery for the shoulder is otherwise required.
Application of cold packs and use of anti-inflammatory medications provide symptomatic relief.
More severe injuries may require surgery to regain strength and functionality in the muscle, particularly in athletes who require complete recovery.