Updated: May 5, 2022
Biceps Tendonitis Cause
Before we get started, it is important to make one point about the naming of this pathology. Biceps tendonitis is actually biceps tendinopathy, similar to what I previously discussed in my post on achilles tendinopathy. The reason for this is that tendonitis refers to inflammation of the tendon being the sole issue and cause of pain. Tendinopathy describes a continuum of issues that include inflammation but also breakdown of the tendon, which is more commonly the cause of pain and dysfunction. I will continue to use biceps tendonitis because it is more common, but it is important to understand the actual pathology.
Understanding the anatomy of the biceps is crucial, so we will start with the basics. There are two heads to the biceps muscle: the long head (red) and the short head (green). The long head originates from the top of the scapula, while the short head attaches to the coracoid process, a lower part of the scapula. Both muscles come together and insert into the radius of your forearm. Their primary action is to flex and supinate the forearm, but they also flex the entire arm as well. The flexing of the entire arm is solely provided by the long head of the biceps.
The long head of the biceps tendon originates from the scapula, but it runs through the bicipital groove, which is a notch formed by the humerus bone. The picture below courtesy of shoulder-pain-explained.com provides an excellent visual.
There is limited space in the bicipital groove, so irritation of the tendon can have significant consequences. Inflammation of the tendon or its sheath can cause the tendon to rub against the bone repeatedly, resulting in more swelling and degeneration. This leads to further inflammation, creating a feedback loop that can result in chronic pain and dysfunction.
The long head of the biceps actually originates from the synovial lining of the glenohumeral joint of the shoulder. This means that any problems with the shoulder can manifest into stress on the long head of the biceps tendon. Many times this can be a result of rotator cuff pathologies or other destabilizing issues in the shoulder.
Repetitive overhead motions can stress the biceps tendon and shoulder, causing irritation in the bicipital groove. Throwing a baseball is a stressful, repetitive, overhead movement that is a common cause of biceps tendon pathologies. In addition, the eccentric stress to the biceps from throwing a baseball can create further damage in the area. The biceps work to decelerate the arm after throwing, creating damage to the muscles and tendon eccentrically.
Tendons can also suffer damage as we age. They can become thinner and lose their recovery abilities, leading to more injuries. Older pitchers are more likely to suffer from biceps tendonitis for these reasons.
Biceps Tendonitis Symptoms
Biceps tendonitis symptoms are relatively easy to differentiate due to their location and nature. Pain will typically be worse with overhead activities such as throwing. Additionally, the pain will often be localized at the bicipital groove. This pain can be provoked by palpating the area and some popping may occur with movements as the tendon slides in and out of the groove. Pain can radiate down the front of the arm, following the path of the biceps. Symptoms can also worsen at night with lying on the affected side.
There are many shoulder pathologies that refer pain to the front of the shoulder and the biceps tendon is often blamed for any pain in that area. However, a healthcare provider who can palpate the affected area and has good differential diagnosis skills should be able to conclude whether or not biceps tendonitis is the cause of symptoms.
Biceps Tendonitis Test
Testing for biceps tendonitis requires a thorough evaluation. There is no single test with good reliability. The most important step is a thorough history to determine when the pain began and what can exacerbate it. Pitchers who had dramatic spikes in workload or changed their mechanics can often irritate the tendon, so it is important to know about any changes on the field.
Palpating the area involves an understanding of the anatomy in the anterior shoulder. The bicipital groove can be felt and the long head of the biceps tendon can be isolated to determine pain and reproduction of symptoms. Blindly poking in the front of the shoulder will inevitably lead to a false positive result, as there are many sensitive structures in the area.
The first special test that can be performed is Yergason’s Test. The image below courtesy of healthjade.net shows the maneuver being performed.
The healthcare provider resists the patient from rotating their arm in the manner shown. If there is pain in the bicipital groove or associated areas, then the test is considered positive.
Speed’s Test is another maneuver to stress the long head of the biceps tendon. It involves the patient raising their arm to 90 degrees in front of them and turning their palm towards the sky. The healthcare provider tries to push their arm down while they resist it. As previously mentioned, the long head of the biceps flexes the forearm and upper arm, so this test provides significant strain on the tendon. The image below courtesy of physiotutors.com shows the test being performed.
Another special test that I like to perform for baseball players is the Biceps Load II Test shown below courtesy of researchgate.net.
The patient can be seated or lying on their back and their shoulder is brought to approximately 90 degrees with their elbow at 90 degrees and palm facing their head. The provider should try to pull the hand away from their head to stress the biceps in an externally rotated position. This is traditionally a test for SLAP tears (read more about those here), but I utilize it for biceps tendonitis as well. The position mimics the stress of throwing in an overhead position and is more useful in baseball athletes.
Imaging of the biceps tendon can be helpful in diagnosing injury, particularly with an ultrasound or MRI. An ultrasound can show any tearing, inflammation, or thickening of the biceps tendon which can determine how much trauma is present. An MRI can do the same while also evaluating the shoulder and surrounding soft tissues to get a better picture of the area around the biceps tendon.