BONES OF THE THORACIC LIMB 179 
osseous space, and is marked in its upper part by the nutrient foramen. From this 
space a vascular furrow descends to the distal part of the shaft, where there is often 
a distal interosseous space for the passage of vessels. The medial surface is exten- 
sive, concave, and smooth. The lateral surface is slightly convex, and its proximal 
part is marked by an oblique rough line or ridge. The proximal extremity is 
large and is bent medially somewhat; its length is more than one-third of that of 
the entire bone. The distal extremity is relatively small; it articulates with the 
ulnar and accessory carpal bones, and is notched in front to accommodate the ridge 
Me: 2 
Fic. 189.—Sketetron or Distat Part or Lerr Tuor- Fic. 190.—Sxereron or Distat Part or Lert 
acic Limp or Pic; Dorsat View. Tuxoracic Limp oF Pig; Vouar VIEW. 
R, Distal end of radius; U, distal end (styloid proc- R, Distal end of radius; U, distal end (styloid proc- 
ess) of ulna; C.r., radial carpal; C. i., intermediate ess) of ulna; C.r., C.%., C.u., C. a., radial, intermedi- 
carpal; C. u., ulnar carpal; C. 2, C. 3, C. 4, second, ate, ulnar, and accessory carpal bones; C. 1—4, first to 
third, and fourth carpal bones; Mc. 2-3, metacarpal fourth carpal bones; Mc. 2-5, metacarpal bones; Ph. 1, 
bones; Ph.1, Ph. 2, Ph. 3, first, second, and third pha- Ph. 2, Ph. 3, first, second, and third phalanges; S, prox- 
langes. imal, and S’, distal sesamoid bones. 
on the radius. The bone contains a considerable medullary canal, and is con- 
solidated at three to three and a half years. 
The carpus comprises eight bones, four in each row. The bones of the prox- 
imal row resemble those of the ox, with the exception of the accessory, which is more 
like that of the horse, but has no lateral groove. The first carpal is small, elon- 
gated from before backward, rounded, and articulates in front with the second carpal. 
The latter is high and narrow, and articulates with the second and third metacarpal 
bones distally. The third carpal articulates with the radial and intermediate 
above, the third metacarpal bone below. The fourth is the largest bone of the row; 
it articulates with the intermediate and ulnar above, the fourth and fifth meta- 
carpals below, and bears a tuberosity on its volar aspect. 
