BONES OF THE PELVIC LIMB 155 
The patella is long, narrow, and very thick. The free surface is strongly con- 
vex and very rough and irregular. The articular surface is convex from side to 
side and nearly straight in the vertical direction. The large prominence on the 
medial side for the attachment of the fibro-cartilage allows prompt determination 
of the side to which the bone belongs. The apex is more pointed than in the horse. 
The tarsus consists of five pieces; the central and fourth and the second and 
third tarsal bones are fused. 
The tibial tarsal bone is relatively long and narrow, and is somewhat flattened 
from before backward. It bears a trochlea at either end. The groove and ridges 
of the proximal trochlea are not spiral, but almost sagittal; the lateral ridge is the 
wider, and articulates with both tibia and fibula. The distal trochlea consists 
of two condyles divided by a groove, and articulates with the 
combined central and fourth tarsals. The plantar surface bears 
a large oval facet for articulation with the fibular tarsal; this 
occupies most of the surface, and is convex and grooved from 
above downward. The lateral surface presents two facets for 
articulation with the fibular tarsal, and is excavated and rough 
elsewhere. The medial surface bears a tuberosity at its upper 
part, and is flattened below. 
The fibular tarsal bone is longer and more slender than in 
the horse. The distal part of the body is compressed laterally, 
and bears a projection in front which articulates with the lateral 
malleolus. The tuber calcis is marked posteriorly by a wide 
shallow groove, which is coated with cartilage in the fresh state. 
The central and fourth tarsals are fused to form a large 
bone (Os centrotarsale quartum, scapho-cuboid), which extends 
across the entire width of the tarsus and articulates with all of 
the other bones. The greater part of the proximal surface is 
molded on the distal trochiea- of-the tibial tarsal, and its medial 
part rises high above the rest posteriorly. Laterally there is a 
narrow, undulating surface for articulation with the distal end 
of the fibular tarsal bone. The plantar surface bears two tuber- 
osities, of which the lateral one is rounded, the medial more 
prominent and narrower. 
The first tarsal bone is quadrilateral and small. It articu- 
lates with the central above, the metatarsus below, and the 
second tarsal in front. Fic. 160—Larce 
The second and third tarsals are fused to form a rhomboid MeraTarsat BoNE 
5 a é : or Ox; Dorsat 
piece. The proximal surface is concavo-convex, and articulates a 
with the central component. The distal surface is undulating 1, Vassular eroove: 
and rests on the metatarsus. The lateral surface bears a small 2, foramen; 3, 3’, con- 
facet in front for the fourth tarsal component, and the plantar 9%" 
surface a very small one for the first tarsal bone. 
The large metatarsal bone is about one-seventh (ca. 3 cm.) longer than the 
corresponding metacarpal. Its shaft is compressed transversely and is distinctly 
four-sided. The groove on the dorsal surface is deep and wide. The plantar 
surface is marked by variable grooves. The proximal foramen on this surface does 
not perforate the shaft, but passes obliquely through the extremity, opening on the 
posterior part of its proximal surface. The medio-plantar angle of the proximal 
end bears a facet for articulation with the small metatarsal bone. 
The small metatarsal bone is a quadrilateral dise a little less than an inch in 
width and height. ~Its anterior face bears a facet for articulation with the large 
metatarsal bone. 
