The biceps muscle has two origins; the short and long head of biceps. The short head of biceps inserts in to the tip of the corocoid process, which is a bony projection off the front of the shoulder blade (scapula). This is located outside the shoulder in contrast to the long head of biceps (LHB), which originates from within the shoulder joint itself.
The LHB passes over the humeral head (ball) within the shoulder joint and then exits the front of the shoulder and merges with the short head to form the biceps muscle. This continues down the front of the arm and inserts into the lower arm just below the elbow. The biceps muscle is responsible for elbow flexion and rotating the forearm such that the palm of your hand can face an upward direction (supination). However, the portion of the long head of biceps that passes within the shoulder joint also acts as a stabiliser to the shoulder.
As the long head of biceps lies within the shoulder joint it can be prone to a number of conditions. These include;
- Biceps tendonitis; the LHB can become inflamed along its course within the shoulder. If this occurs one can experience anterior shoulder pain which is made worse by lifting with an outstretched arm or when using the arm overhead. The tendon can often be tender to touch at the front of the shoulder.
- Biceps tear / rupture; a normal long head of biceps tendon can rupture if it is suddenly overloaded when performing heavy lifting. However, it more commonly ruptures after it has undergone degenerative change and it is therefore often associated with rotator cuff disease. If the LHB ruptures it can result in the LHB tendon becoming more prominent in the upper arm such that it is called a ‘Popeye Sign”.
- Biceps instability; after passing through the shoulder joint, the LHB exits the front of the shoulder and continues down the arm. Where it exits the shoulder the tendon sits in a shallow groove. Its position within this groove is dependant on its neighbouring rotator cuff tendon (subscapularis) being intact. If there is a subscapularis tendon tear, then the biceps tendon may slip out of its groove. This can cause pain and if it occurs repeatedly, it may result in tendonitis and ultimately a rupture of the long head of the biceps and/or further damage to the subscapularis tendon.
Causes & Risk factors
- Pre-existing rotator cuff degenerative changes
- Frequent use of the arm at, or above, shoulder height
The diagnosis is based on a clinical examination which may be supplemented with either an ultrasound or MRI scan to gain further information about the quality of the long head of biceps and its surrounding rotator cuff tendons.
There are a number of treatment options available for biceps related pathology and the choice of treatment is dependant on the type and extent of injury. Often more than one treatment modality may be used to ensure maximum effect.
The options include;
- Conservative treatment comprising of rest, activity modification and the use of anti-inflammatory medications.
- Physiotherapy; a stretching and eventually a strengthening physiotherapy regime can be used to improve the dynamics of shoulder movement and can also be used balance the stabilising muscles of the shoulder. Strengthening exercises to the rotator cuff tendons can also prove helpful to minimise any abnormal stresses to the long head of biceps tendon.
- Injection treatments; if there is inflammation around the biceps tendon then an injection of local anaesthetic and cortisol can be placed in the biceps sheath. The anti-inflammatory component of the injection can reduce swelling and pain and can be used in conjunction with physiotherapy to aid recovery.
- Arthroscopic debridement; if the long head of biceps tendon has developed a tear in its structure this can often be visualised at the time of a shoulder arthroscopy. Providing the tear isn’t too severe, symptomatic benefit can be achieved by debriding the tear back to a smooth surface such that shoulder movement no longer aggravates the torn surface. If the size of the LHB tear is too large, then a biceps tenodesis or tenotomy may have to be considered. This can be performed as a ‘key-hole’ procedure through 2 or 3 small incisions.
- Biceps tenodesis; in this procedure the long head of biceps is detached from within the shoulder and reattached to the humerus just outside of the shoulder joint. This therefore removes the LHB from within the joint, which is where it is being aggravated. This procedure is usually performed as an arthroscopic operation and would therefore involve 2 or 3 small incisions measuring approximately 1 cm in length. If there is an associated rotator cuff tendon tear then a rotator cuff repair might also be needed. The nature of the operation would be dependant on the location and the size of the rotator cuff tear.
- Biceps tenotomy; if the degree of tendon degeneration, or the size of the tear, is too great to preserve the LHB, it can be cut (tenotomised). This releases the tendon and allows it to retract down the arm and out of harms way. This usually gives good symptomatic benefit and is often an appropriate treatment when the biceps pain is associated with a large irreparable rotator cuff tear. As the tendon is not fixed back to the humerus it may retract down the arm resulting in a ‘Popeye sign’.