180 SKELETON OF THE PIG 
Four metacarpal bones are present. The first is absent, the thyyl and fourth 
are large and carry the chief digits, while the second and fifth are much smaller and 
bear the accessory digits. Their proximal ends articulate with each other and with 
the carpus as indicated above. The distal ends fuse with the shafts at about two 
years of age. 
The third and fourth metacarpals are flattened from before backward, three-sided, and 
placed close together. The distal end of each bears a trochlea for articulation with the first 
phalanx and the sesamoids. The third is the wider of the two, and articulates with all of the distal 
row of the carpus except the first. The fourth articulates with the fourth carpal chiefly, but has a 
small facet for the third. The second and fifth metacarpals are placed further back than the chief 
bones. The fifth is considerably the thicker of the two. The proximal ends are small and articu- 
late with the corresponding carpal and metacarpal bones. The distal end is relatively large; its 
articular surface is condyloid in front, trochlear behind. 
Each chief digit comprises three phalanges and three sesamoids. The bones 
of the chief digits resemble those of the ox in form, but there is no foramen on the 
interdigital side of the extensor process and the proximal sesamoids are narrow and 
ridged behind. The phalanges of the accessory digits (which do not reach the 
ground ordinarily) are similar in form but much smaller. Fusion of the proximal 
ends with the shafts takes place at about two years for the first phalanges, at about 
one year for the second phalanges. 
Crest of ilium Gluteal line 
Tuber sacrale 
Ischiatic Lesser sciatic Tuber 
Greater spine notch ischit 
sciatic notch 
Tuber core Ilium (shaft) 
Acetabulum Tschium 
Fig. 191,—Lerr Os Cox or Pia; Larerar Vinw. 
Tuber sacrale Crest of ilium 
Lesser 
Tuber sciatic Ischiatic 
ischit notch spine 
Auricular Tuber coxe 
‘Soas 
Psoas surface 
tubercle 
Tlio-pectineal 
eminence 
Pubis (acetab- 
ular branch) 
Obturator 
foramen 
Fic. 192.—Lerr Os Cox or Pia; Mepiau View. 
BONES OF THE PELVIC LIMB 
The os coxe is long and narrow. The ilium and ischium are almost in line 
with each other and nearly sagittal in direction. The wing of the ilium bends out- 
ward much less than in the horse or ox. The gluteal surface is divided into two fossx 
