Ruptured head of right biceps muscle in arm. This may be seen as the unusual bulge just above the elbow on the forward side of the arm. The biceps muscle has two heads which are fixed to the shoulder. Rupture of one of the heads may occur in trauma or in rheumatoid arthritis, and is a risk in local steroid injection. There is minimal disability in this condition as the remaining head can perform most of the muscle's tasks.