30 PROFESSOR STRUTHERS. 



olecranon for 2J inches (If of it on the cartilaginous olecranon), 

 with a partial deficiency across the sigmoid cavity, as in man ; 

 and was also continued in between the epiphysis of the radius 

 and ulna for 1J inches. The facet of the humerus for the 

 radius is almost flat ; that for the ulna concave both ways, the 

 hollow J inch deep, till near the olecranon part where it be- 

 comes convex. The synovial membrane of the elbow passed 

 over the edges of the bones for J inch, until it met the liga- 

 ments. The elbow-joint allowed of a very little gliding motion. 



8. THE CAKPUS. The carpus has six cartilages, representing 

 bones, four in the proximal row, the radiale, intermedium, 

 ulnare, and pisiforme ; two in the distal row, in series with 

 digits III. and IV. (see figures 6 and 9). Only the radiale 

 and ulnare have ossification, seen only in section. The posi- 

 tion and relative size of these small ossifications are shown in 

 figure 9, as are also the ossification within the epiphysis of 

 the radius, and the very small ossification within the epiphysis 

 of the ulna. The cartilages representing the future carpal bones 

 are well marked out on both the flexor and extensor aspect by 

 surface grooves, bridged over by fibrous tissue, and the separa- 

 tion of the cartilaginous blocks goes through and through, the 

 narrow interval occupied by soft connecting fibrous tissue, 

 resisting the handle of the knife and allowing of a little motion. 

 This is beautifully seen on horizontal section of the entire 

 carpus, the great blocks of cartilage mapped out sharply as in 

 an outline diagram. The numerous vascular perforations are 

 seen over the whole area of the cartilages. The lines of articu- 

 lation, occupied by the soft fibrous tissue, vary in width from 

 T l g inch to half that or less. The same kind of articulation, by 

 intervening fibrous tissue, is seen at the wrist-joint, but with a 

 somewhat wider interval (about ^ inch), and at the carpo- 

 metacarpal articulations. 



Synovial cavities exist at both the proximal and distal ends 

 of the cartilage of the second row (os magnum) which supports 

 digit III. The proximal of these cavities reaches across the 

 whole breadth of the end (2 inches). The distal cavity covers 

 only about a fourth (1 inch) of the distal end, where the 

 cartilage forms a blunt peak. Both of these synovial cavities 

 go through and through from flexor to extensor aspect. It will 



