A biceps tendon injury is a tear or rupture of connective tissue that connects the biceps muscle of the upper arm to bones at either the shoulder (proximal tendon) or elbow (distal tendon). Proximal tears are more common than distal tears and usually are the the result of chronic overuse or an acute injury, such as a direct blow to the shoulder or falling onto an outstretched arm.
Source: Verywell Health