The bicep is a muscle that acts primarily as an elbow flexor and helps stabilize the shoulder during elevation. Most injuries to the biceps are secondary to repetitive lifting or overhead activities. Micro traumas are usually the cause of the bicep tendinopathy.
Biceps overuse injuries are often miss diagnosed as rotator cuff pathology- with good reason, bicep tendinopathy rarely is an isolated incident and is highly correlated to impingement syndrome.
The long head of the bicep attaches to the superior anterior labrum and are involved in type II and IV slap lesions. SLAP lesions can be caused by progression on impingement, anterior instability, faulty biomechanics and peel back theory during cocking phase of throwing, inability to adequately decelerate the arm during throwing motion.
As noted above the bicep is highly correlated with impingement. The long head of the bicep lies in between the humorous and the acromion. Improper muscle balance and biomechanics can cause repetitive stress/trauma to the bicep tendon in overhead activity. The short head of the bicep attaches to the acromion process along the with the PEC minor. If tight, the short head may cause increase anterior tilt of the scapula, thus creating more impingement.
Biceps tendinopathy can be divided into tendonitis and tendinosynovitis. Tendinitis is a chronic overload that leads to microscopic tears triggering tissue damage and inflammation. Tendonosynovitis is direct injury or irritation in the sheath of the tendon as it rubs or glides over a boney prominence.
Three types of etiology
1. Mechanical- repetitive stress
2. Vascular- Vascular compromise
3. Neural- Nerve compromised and release of substance P (causes chronic inflammatory response)
DTR C6 bicep reflex