skeleton 1: Skeleton of Adult Man Head: see illustration at SKULL. Chest: 1 manubrium, 2 gladiolus, 3 xiphoid process, 4 to 10 true ribs: first to seventh ribs inclusive, 11 to 13 false ribs: eighth to tenth ribs inclusive, 14 and 15 floating ribs, a costal cartilage. Trunk: 16 first thoracic vertebra, 17 twelfth thoracic vertebra, 18 fifth lumbar vertebra, 19 fifth sacral vertebra, 20 coccyx. Upper Extremity--shoulder: 21 clavicle, 22 scapula. Upper Extremity--arm: 23 humerus, 24 ulna, 25 radius, b bones of forearm in prone position, c same in supine position. Bones of the hand see illustration at HAND. Lower Extremity--bones and principal parts of pelvic girdle: 26 ilium, 27 ischium, 28 pubis, 29 sacrum, 30 pelvic brim, 31 pelvic cavity. Lower Extremity--bones of the leg: 32 femur, 33 patella, 34 tibia, 35 fibula. Bones of the foot see illustration at FOOT