8o 



ELEMENTS OF MAMMALIAN ANATOMY 



The head bears a convex surface for articulation with the 

 navicular. The neck is the constricted portion between the 

 body and the head. 



The scaphoid lies on the medial side of the foot and articu- 

 lates with the remaining six bones of 

 the tarsus. It may be recognized by 

 its deep concave surface for articula- 

 tion with the talus, and also by the 

 tuberosity, a process on its medial 

 plantar angle (Fig. 44). 



The internal cuneiform is next to the 

 smallest bone of the tarsus. It articu- 

 lates with the navicular, middle cunei- 

 form, and first and second metatarsals. 

 The fuiddle cuneiform is a wedge- 

 shaped bone and the smallest element 

 of the tarsus. It articulates with the 

 other two cuneiforms, the scaphoid and 

 second metatarsal. The external cunei- 

 form may be recognized by a strong 

 hook-like process on its plantar surface. 

 It articulates with the scaphoid, mid- 

 dle cuneiform, cuboid, and second and 

 third metatarsals. 



The cuboid is the lateral bone of the 

 distal row. It may be recognized by 

 the deep groove on its plantar surface 

 which shelters the tendon of the per- 

 oneus longus muscle. 



The typical arrangement of the tar- 

 sal elements in vertebrates is similar to 

 that of the carpus. Three bones, a 

 tibiale, intermedium, and fibtdare, com- 

 pose the proximal row, while five tarsalia form the distal row. 

 The centrale occupies the center of the tarsal region. In the 



Fig. 44. — Dorsal Aspect 

 OF Left Hind-foot. 

 ag, Talus; ar, articular 

 surface of the tibia; cb, 

 cuboid; ec, external cunei- 

 form; gr, groove for the ten- 

 don of the plantaris; h, head 

 of the fourth metatarsal; ic, 

 internal cuneiform; 7nc, 

 middle cuneiform; Wi, hal- 

 lux or first metatarsal; W2, 

 W3, ni4, and ws. second, 

 third, fourth, and fifth 

 metatarsals; nv, navicular 

 or scaphoid; oc, os calcis, 

 or calcaneum; 3, proximal 

 row of phalanges; .2, middle 

 row of phalanges; i, distal 

 row of phalanges. 



