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 



Fig. 228. — Skeleton of Distal Paht of Left Pelvic Limb op Dog; Dorsal View. 

 L, Lateral malleolus (distal end of fibula); T. t., tibial tarsal bone; T. f., fibular tarsal bone; T. c, central tarsal 

 bone; T. 2, T. 3, T. 4, second, third, and fourth tarsal bones; P. l-\- 2, fused first and second phalanges, and P. 3, third 

 phalanx, of first digit; Mc. o, 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. 



