EXTREMITIES. 19 



Superior extremity : olecranon, its tuberosity and beak, 

 sigmoid notch. Inferior extremity : sharp. 

 Development : two centres of ossification. 



Digital Region. 



Carpus. — Offers six faces ; anterior face : convex ; 

 posterior face : very rough and irregular ; superior and 

 inferior faces articular ; two lateral faces : rough. It 

 is composed of seven or eight bones arranged in two 

 rows. Superior row has four bones : the trapezium 

 with two facettes, the cuneiform with five, the lunar 

 with six, the scaphoid with four. The inferior row 

 has three bones; the unciform wdth four facettes, the 

 magnum with seven, the trapezoid with five. 



Development : each one centre of ossification. 



Metacarpi. — Three. Principal. — Body has an an- 

 terior face, smooth and convex ; a posterior face, with 

 nutritive foramen, articular surfaces for rudimentary 

 metacarpi ; superior extremity, flat f accettes for the 

 carpus ; inferior extremity, with two condyles, median 

 spine, cavities on each side. 



Development: two nuclei of ossification. 



HuDiMENTARY. — Tlircc faccs ; a superior extremity : 

 articular ; an inferior, w^ith button. 



Development : one nucleus of ossification. 



