THE SKELETON 3 1 



In the lower vertebrate generalized carpus two of the carpal 

 bones are alhgned with the antibrachial, and five with the 

 metacarpal bones, and there are the two indifferently placed 

 bones (lunate and central), which form the ''middle row" of 

 some authors. The proximal row is comprised of the radiale 

 (navicular) which Ues at the end of the ulna, and the inter- 

 medium and the centrale (central). The bones of the second, 

 or distal row are given the same ordinal name as that of the 

 metacarpal with which each articulates. Thus, the first carpal 

 (beginning on the radial side) articulates with the first meta- 

 carpal and it and the other four are known as carpale I (trape- 

 zius), carpale II (trapezoid), carpale III (os magnum), 

 carpalia IV and V (unciform). A study of the generalized 

 low vertebrate type will aid the student greatly in mastering 

 the carpus and its relations in the rabbit and in man. The 

 pisiform bone forms a conspicuous protuberance on the 

 caudal side of the carpus, for the insertion of the flexor carpi 

 ulnaris m. (29), articulates with the proximocaudal surface 

 of the triquetral and with the caudal surface of the styloid 

 process of the ulna. It is not visible on the cranial surface of 

 the carpus. 



The metacarpus has five metacarpal bones and five paired 

 sesamoid bones, one pair on the ventral side of each meta- 

 carpophalangeal articulation, which form grooves through 

 which flexor tendons pass. 



The phalangeal bones are five in the proximal, four in the 

 middle, and five in the distal rov/. The distal (ungual) phalan- 

 ges terminate in claw-shaped bony processes which, in life, are 

 covered by the nail or claw. 



e. THE PELVIC GIRDLE AND INFERIOR LIMB 



The pelvic girdle (Fig. 14) is formed by a right and a left 

 innominate bone which are firmly articulated with the auricular 

 processes of the sacrum and with each other through the pubio- 

 ischial symphysis. The three major component parts of the 



