580 



MAMMALIAN ANATOMY 



of the lower end of the ulna to a greater or less degree according as 

 the hand is held with the palm downward and backward or is turned 

 inward. As a cat is unable to turn the palm of the hand directly 

 forward without rotating also the humerus, the lower end of the radius 

 can never lie wholly on the outer side of the lower end of the ulna. 

 The shaft of the radius is parallel with the shaft of the ulna, or may 

 cross it obliquely from above, downward, and inward, the ordinary 

 position in walking. The radius articulates by its proximal end with 

 the distal end of the humerus and with the contiguous side of the ulna, 

 and by its distal or lower end not only with the scapho-lunar, the 



Metacarpus. 



Metatarsus. 

 Phalanges. 



THE SKELETON OF THE CAT. (LEFT SIDE ONLY.) 



principal bone in the proximal row of the carpus, or wrist, but also 

 .with the lower end of the ulna. Its shaft is bound to the shaft of the 

 ulna by a strong interosseous ligament. The radius can be felt through 

 the muscles of the forearm, and its outer edge is almost subcutaneous. 

 The proximal end of the radius is smaller than the distal end. The 

 shaft is arched from above downward, and the convexity of the arch is 

 on the back of the forearm, which in walking faces forward. It is also 

 slightly arched away from the ulna. For convenience of description, 

 the bone may be held with the concave surface in front. The radius 

 has three well-marked parts, the upper extremity, the shaft, and the 

 lower extremity. 



The Upper Extremity comprises about one-ninth of the length of 

 the entire bone. It is subcylindrical in shape and bent outward and 



