Description
A top sirloin is composed of two main parts, the sirloin cap (biceps femoris) and the center sirloin (gluteus profundus, gluteus accessorius, and gluteus medius). The gluteus profundus and the gluteus accessorius are small muscles and can be considered accessory muscles. A top sirloin butt, cap-off is the center sirloin with excess fat and the accessory muscles excluded.