Biceps Tendonitis

The biceps tendon is a very common cause of pain in the front of the shoulder. It commonly affects those with poor shoulder mechanics (see article on shoulder pain), poor posture and those who repeatedly overuse the tendon such as tennis players and new mothers!

The biceps tendon is split into two.  Both heads insert onto the scapular (shoulder blade) and the other end also splits into two eventually and inserts onto the radial head and blends with the muscles of the forearm.  The main action of the biceps is to turn the palm from facing downwards to facing upwards (supination).  Although, most people in the gym and some personal trainers would have you believe that the main action is to flex the elbow (reduce the angle between the forearm and the upper arm (humerus).  Next time you are in the gym try performing a bicep curl with your palms facing downwards (pronation).  Not only will you not be able to lift as much but also you will notice that the bulge in your perfectly formed biceps is no longer there anymore!  This is because you have just ‘deactivated’ the biceps by performing the bicep curl with the forearm in a pronated position; this is a simple biomechanical fact!

Now the end of the biceps that seems to give the most problems is by far most commonly the upper end and more often than not the longer head of the biceps, which attaches to the superior glenoid tubercle of the scapular (a small bump above the socket of the shoulder joint).  This tendon runs through a small groove in the humerus (upper arm) and folds the joint capsule back on itself before attaching here.  The space in which this tendon and the rotator cuff tendons attach to the humerus is very narrow, as is quite a ‘traffic jam’ of tendons, bursae (fluid filled sacks), ligaments and joint capsule.

The problem arises when faulty shoulder mechanics overload the posterior (at the back) supporting muscles, leading to strain on these structures and subsequent lengthening of the muscles.  Reciprocally, at the front of the joint the muscles shorten (pectorals, subscapularis, latissimus dorsi) leading to a forward’s movement and an internal rotatation of the head of the humerus (upper arm bone).  If you remember back to the anatomy of the shoulder joint the long head of the biceps runs within a groove on this bone and is firmly attached to the scapular, which does not move also.  This ‘bullying’ of the tendon results in stress from behind the biceps tendon, as the head of the humerus moves forwards into the back of the tendon and thus in effect causing a stretch on the tendon.  Therefore, even before the biceps contracts in this position it is being stretched in the groove of the humerus and therefore starts from a disadvantageous position, leading to strain of the tendon.  This results in inflammation and micro trauma to the tendon, which lead to further damage and what you will feel as pain on lifting things.  If this progresses further damage will result and could potentially lead to rupture or more chronic tendon changes, which need operative intervention.  The early signs of this would be pain on lifting objects and activities such as brushing your teeth, which require rapid movement of the biceps tendon in the groove in an abducted position.  Press ups and bench presses in the gym or serving in tennis are activities which can cause overuse of the biceps tendon and damage (amongst a few other things).

Another cause for excessive strain on the tendon would result from reduction in the space underneath the tip of the shoulder, where the rotator cuff tendons and biceps insert.  This may occur slowly or quickly depending on the nature of the injury.  Slow injuries result from overuse, whereas the quicker injuries result from things like falls when skiing.  Both are treated very differently in the early and late rehab phases.  Subscapularis plays a very important role in keeping the space underneath the acromion (tip of the shoulder) open, proper functioning and corrective exercises are vital in the rehabilitation of this damaging problem.

Proper diagnosis and early intervention is key in the management of biceps tendon damage.  Feel free to contact us to find out more about shoulder pain and biceps tendon damage, whether you are a professional sports person (of which we see lots with this problem) or a new mother (lifting babies is a common cause of this problem), it is possible to correct the problem and reduce further suffering.

Leave a Reply