THE HORSE. 
the other two, which, from thus supporting, are sometimes called splint 
bones. 
Tue Metacarpus Maenvs, or cannon-bone, has a body and two extremi- 
ties, the superior of which articulates with the carpus while the inferior 
rests upon the next phalanx, or great posterior bone. (See Fig. 26.) 
THE BopyY is convex and smooth, anteriorly and late. 
rally ; thus forming two-thirds of a cylinder. Poste- 
riorly it is flattened ; its sides, extending from above, 
downwards, to about three inches above its inferior 
extremity, present two triangular scabrous surfaces ; on 
the upper parts of which two smooth articulatory spots 
occur, to which the small metacarpal bones are attached. 
THE SUPERIOR EXTREMITY presents a smooth articu- 
latory surface which is, for the most part, flat ; it slopes 
off, however, on its outer side for articulation with the 
os unciforme. There is also another small spot which 
slightly declines, situated at the outer side of the head of 
the inner small metacarpal bone. This spot articulates 
with the postero-inferior surface of the os trapezoides. 
The flat surface articulates with the os magnum, to which 
it corresponds in figure. Its anterior and lateral edges 
are somewhat roughened. 
THE INFERIOR EXTREMITY presents two smooth condy- 
loid surfaces, separated by a smooth semicircular emi- 
nence, which articulate with a corresponding formation 
on the superior extremity of the os suffraginis. On the 
sides of each of the condyles a depression occurs. 
Ossa Metacarri Parva are in number, two; ex- 
ternal and internal. In form they are pyramidal, pre- 
senting bases turned upwards, apices downwards, and 
bodies or middles. 
THE BASE is surmounted by a smooth articulatory 
surface, surrounded inferiorly by roughened tuberosities, 
except anteriorly, where two smooth articular surfaces 
occur, which articulate with corresponding surfaces men- 
tioned as existing on the metacarpus magnus. 
THE Bopy is trifacial. The anterior surface is rough, 
and articulates with the metacarpus magnus. The inner 
surface is excavated. The outer surface is convex and 
340 
Fia. 29.—Back View 
or THE LARGE AND 
SMALL METACAR- 
PAL BONES. 
2. Metacarpus mag- 
nus. 
8. Thesurfaces above 
articulate with 
the lower carpal 
bones. 
4, 4, External and in- 
ternal small me- 
tacarpal bones. 
5. 5. Condyloid sur- 
faces articulat- 
ing with corre- 
sponding ones 
on the upper ex- 
tremity of the 
os suffraginis. 
smooth. The apex terminates in a bulbous extremity, 
which looks posteriorly, and does not articulate with 
the metacarpus magnus. 
6. Eminence articu- 
lating with a 
corresponding 
depression on 
the upper ex- 
tremity of the 
os suffraginis. 
THE PHALANGEAL BONES (PASTERNS 
AND FOOT). 
BrYOND THE METACARPUS in the horse, there is only 
a single bone in each joint, the five fingers being 
merged in one. The same number of phalanges, however, is maintained, 
counting from the metacarpus to the distal phalanx, which is the pedal 
bone. ‘The whole may, therefore, be considered as analogous to one 
human finger, with the addition of the two sesamoid bones, and tho 
navicular bone, all three of which are intended to assist in giving leverage 
to the tendons moving these parts. The highest of these is the os suffra- 
