36 DESCRIPTION OF THE SKELETON. 



The body, or shaft, of the radius is slender and twisted. It has three 

 edges. The anterior edge extends from the outer part of the upper, to 

 the anterior part of the lower extremity. The inner edge is rounded, and 

 not well defined. The external edge is sharp, and corresponds with the 

 inner edge of the ulna for a considerable extent. The interosseous space 

 is scarcely sensible. The lower extremity of the radius is much larger than 

 the upper; it has a considerable tuberosity on its inner edge (Plate XL B), 

 and is connected with the two internal carpal bones, which are the 

 scaphoides and semi-lunare. 



The length of the radius is twenty-nine inches ; the breadth of its 

 carpal extremity, six inches and a half. The entire circumference of the 

 elbow-joint is forty-four inches, 

 uina. Ulna (Plate XXV.). — The ulna is much the largest of the two bones 



of the fore-arm, and is the great support of the limb. It has an immense 

 olecranon, very long, thick, and rough, terminating in something like a 

 neck ; whence proceeds a process to the groove between the condyles, pre- 

 senting an articulating surface for each of these, as before stated. 



The body of the ulna has three edges and three faces. The pos- 

 terior edge is a continuation of that from the olecranon process, and 

 terminates in the back part of its inferior extremity. The external edge 

 of the ulna, beginning at the external part of the head of the bone, con- 

 tinues regularly downwards to the anterior part of the inferior condyle. 

 The internal edge, proceeding from the internal part of the head of the 

 bone, becomes less defined below, and terminates near the lower extremity 

 of the radius. 



Of the faces of the ulna the anterior is smooth and regular. It is 

 covered in part superiorly by the radius; inferiorly it is uncovered and 



