30 ANTHROPOLOGY. 



The forearm {pi. 122, fig. 3, d) is composed of tlie ulna and radius. 

 Of these, the uhia or cubitus {figs. 3", 15') is situated at the inner side 

 of the forearm, forming the principal part of the elbow ; it does not directly 

 enter into the wrist joint, but falls a little short of it below ; it is divided 

 into the body and two extremities. The upper extremity is the larger, and 

 presents two processes and an intervening cavity. The posterior process, 

 or the olecranon {figs. 16, 17, and 18), is the highest part of the bone : 

 posteriorly it is smooth ; anteriorly it is also smooth, and covered with car- 

 tilage. The coronoid process {fig. IT'') is anterior and inferior to the 

 23receding. Externally it is hollowed out into the lesser sigmoid cavity 

 {fig. 17') which receives the head of the radius; superiorly it leads into 

 the great sigmoid cavity {fig. 16') which moves on the trochlea of the 

 humerus in flexion and extension of the forearm ; the profile of this cavity 

 resembles the letter C. The lower or carpal end {fig. 21 '■°) is small and 

 round, with two eminences. The external is named the head; it is round, 

 and covered with cartilage, and received into the cavity in the inner border 

 of the radius. The internal eminence, or styloid process {fig. 21 ^), is more 

 prominent, and on a level with the posterior surface of the bone. The ulna 

 articulates above with the humerus and radius, and below with the radius 

 and interarticular cartilage. 



The radixLs {figs. 3", 15°) is shorter than the ulna, and, while only 

 accessory as a rotating bone in the elbow, it is the principal bone in the 

 carpal joint. It is divided into the body and two extremities. The upper 

 or humeral end presents a head, neck, and tubercle. The head {fig. 19 ') 

 is a circular superficial cavity, with the surface and circumference covered 

 with cartilage, the former to articulate with the small head of the humerus, 

 the latter with the sigmoid cavity of the ulna and with the annular ligament. 

 The neck {fig. lO'') is nearly an inch long, descends obliquely inwards, and 

 is contracted and circular. At its lower extremity, where it joins the shaft, 

 is the tid)ercle {fig. 19'). The body or shaft is somewhat triangular, and pre- 

 sents three surfaces, separated by three margins or angles. The lower or 

 carpal end of the radius is irregularly square ; its anterior prominent edge 

 gives attachment to the anterior carpal ligament. Posteriorly there are 

 seen three grooves : one nearly in the middle line, the second at the ulnar 

 side of this, and the third on the radial side. The styloid process is the 

 inferior extremity of the radius ; from its point arises the external lateral 

 ligament of the wrist. 



The hand {pi. 122, fig. 3 E ; ^Z. 123, figs. 46 and 47) consists of the carpus, 

 metacarpus, and phalanges ; twenty-seven bones in all. 



The carpus is composed of eight bones, arranged in two rows : the first 

 row consists of the scaphoid, lunar, cuneiform, and pisiform ; the second of 

 the trapezium, trapezoid, magnum, and unciforme ; enumerating them from 

 the radial to the ulnar side, or from without inwards. 



The scaphoides or navicular bone {pi. 12^^ fig. 47'). This is the largest 



in the upper row, and is situated at its outer or radial side. It presents four 



articular surfaces, by which it articulates with the radius, the trapezium, the 



trapezoid, the lunar, and the magnum. The lunare or semicircular bone 



736 



