BONES OF THE PELVIC LIMB 



135 



tuberosities, of which the outer one is rounded, the inner more prominent and nar- 

 rower. 



The first tarsal bone is quadrilateral and small. It articulates with the central 

 above, the metatarsus below, and the second tarsal in front. 



The second and third tarsals are fused to form a rhomboid piece. The proxi- 

 mal surface is concavo-convex, and articulates with the central component. The 

 distal surface is undulating and rests on the metatarsus. The external surface 

 bears a small facet in front for the fourth tarsal component, and the posterior sur- 

 face 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 laterally and is distinctly 



Central 4- fourth tarsal bone 

 First tarsal bone 



Tibial tarsal bone 



Second + third tarsal bone 



25 



Proximal sesamoid 



Distal sesamoid 



Fig. 104. — Skeleton of Distal Part of Left Hind Limb of Ox, Internal View. 

 £4, Tuber calcis; ^5, large metatarsal bone; 30, first phalanx; 31, second phalanx; 3^, third phalanx. 



Ellenberger-Baum, Anat. fiir Kiinstler.) 



(After 



four-sided. The groove on the anterior surface is deep and wide. The posterior 

 surface is marked by variable grooves. The upper 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 postero-internal angle of the proximal 

 end bears a facet for articulation with the small metatarsal bone. 



The small metatarsal bone is a quadrilateral disc a little less than an inch in 

 width and height. Its anterior face bears a facet for articulation with the large 

 metatarsal bone. 



The large metatarsal bone is usually regarded as consisting of the fused third and fourth 

 metatarsal bones. The medullary cavity is subdivided like that of the large metacarpal bone, 

 borne anatomi.sts, however, consider that the ridges at the upper end of each border represent the 

 second and hfth metatarsals (Rosenberg and Retterer). On this basis the small bone would be 

 the nrst metatarsal. 



