206 THE ARTICULATIONS OR JOINTS 
first tarsal and furnishes insertion to the tibialis anterior muscle. In some cases 
it fuses with the first tarsal; when the first digit is well developed, its metatarsal 
may resemble the others (except in size) or be reduced in its proximal part to a 
fibrous band. The other metatarsals are a little longer than the corresponding 
metacarpals. Their proximal ends are elongated from before backward and have 
plantar projections, which in the case of the third and fourth usually have facets 
Fic. 228.—SkeLeton or Distau Part or Lerr Petvic Limes or Doc; Dorsau View. 
L, Lateral malleolus (distal end of fibula); 7. ¢., tibial tarsal bone; 7. f., fibular tarsal bone; 7’. c., central tarsal 
bone; 7. 2, T. 3, T. 4, second, third, and fourth tarsal bones; P. 1+ 2, fused first and second phalanges, and P. 3, third 
phalanx, of first digit; Mc. 5, fifth metacarpal bone; P. 1, P. 2, P. 3, phalanges of fifth digit; S, dorsal sesamoid. 
for articulation with two small rounded sesamoid bones. In other respects they 
resemble the metacarpals. 
The first digit is often absent. When present, its development varies and it 
contains one or two phalanges. In other cases—especially in very large dogs— 
a sixth digit is present; it does not articulate with the metatarsus, but is attached 
by fibrous tissue. The phalanges of the other digits resemble those of the tho- 
racic limb. 
Ossification of the metatarsal bones and phalanges is complete at five or six 
months. 
