The photo shows  the central third of the patellar tendon used as a graft for the arthroscopical reconstruction of the anterior cruciate ligament. The central tendon part (tend), is inserted on an osseous block at the two ends (os - bone). This is our preferred graft. The blue line indicates to the surgeon the limit between the tendon and the bone at the time of the arthroscopical reconstruction to assure good fixation of the transplant by the interference screws.