Fabella bone is identified as an accessory and evolutionary sesamoid bone in humans. It was noticed as an irregular shape located within the lateral head of gastrocnemius in the posterolateral capsule of the left knee of a 55-year-old male. Another smaller fabella was noted and both were kept in a safe place Measurements were taken after a week and their length was 2.7 cm and 1.8 cm respectively. The size of fabella usually ranges from 5mm-20mm in diameter, but in this study, the length of the larger one was 2.7 cm. Fabella originated as a small cartilaginous nodule and underwent endochondral ossification. It helps to reduce resistance within tendons and redirect muscle forces. In humans, gastrocnemius acts to flex the knee and plantar flex the foot. Fabella function was thought to stabilize the femoral complex and medial femoral condyle. Patients with fabella pain syndrome usually complain of increased posterolateral pain during the full extension of the knee joint. Fabella pain syndrome could be treated with physical therapy, local anaesthetics injection, radial extracorporeal shock wave therapy or fabellectomy. It has been observed that there has been an increase in the prevalence of fabella in recent years. Larger moments acting on the knee and increasing muscle or tendon strain could produce stimuli essential to encourage fabella formation.