The biceps tendon is the attachment of the biceps muscle to the bone. The biceps muscle is named because there are two tendon attachments (therefore, "bi"-ceps) in the shoulder, and there is also a tendon attachment of the muscle below the elbow.
The biceps muscle is important both in bending the elbow (flexion) as well as turning the forearm upwards (supination). Biceps tendon tears can diminish the strength of these movements and can also cause a deformity of the biceps muscle.
The most common type of biceps tendon tear is a detachment (partial or complete) of one of the biceps tendons within the shoulder joint. There are two attachments of the biceps tendon at the shoulder, one within the shoulder joint (the long head of the biceps), and the other is in front of the shoulder joint (the short head of the biceps).