Each arm and each leg contains 30 bones. Flexors work antagonistically with extensors. E.g. each arm contains humerus in the upper arm, radius and ulna in the forearm, 8 carpals in the wrist, 5 metacarpals in the palm and 14 phalanges in the fingers. Each hind limb contains femur in thigh, patella in knee, tibia and fibula in shank, 7 tarsals in ankle, 5 metatarsals in sole and 14 phalanges in toes.