BONES OF THE PELVIC LIMB 



167 



It is almost circular in the female, 



The symphyseal part of the pubis is thick and fuses late with the opposite bone. 

 There is no subpubic groove. 



The acetabulum is about twice as far from the external angle of the ilium as 

 from the tuber ischii. The fossa acetabuli is deep, and is bounded internally by a 

 flat plate of bone; its floor is so thin as to be translucent. There is a small notch 

 behind. 



The obturator foramen resembles in outline an equilateral triangle with the 

 angles rounded off. 



The inlet of the pelvis is very oblique, 

 but in the male it is elliptical and the con- 

 jugate diameter is the longer. The cavity is 

 narrowest between the acetabula, and very 

 wide behind. The floor is concave and rela- 

 tively narrow in front, wide and flat behind. 



The femur is relatively much longer than 

 in the horse or ox. Tlu^ shaft is regularly 

 cylindrical, except near the extremities, where 

 it is wider and compressed from before back- 

 ward. It is strongly curved in its lower two- 

 thirds, convex in front. The posterior surface 

 is flattened transversely, narrow in the middle, 

 and widens toward each end. It is bounded 

 by two rough lines (Labium laterale, mediale) 

 which diverge toward the extremities. The 

 third trochanter and the plantar (supracondy- 

 loid) fossa are absent. There are two supra- 

 condyloid crests, the inner one being small. 

 The nutrient foramen is in the upper third of 

 the posterior surface. The head is a little more 

 than a hemisphere and has a shallow depression 

 -behind and external to its center. The neck is 

 well defined. The trochanter major does not 

 extend as high as the head ; a thick ridge runs 

 from its anterior surface to the neck. The in- 

 ternal trochanter has the form of a blunt tuber- 

 osity. The trochanteric fossa is round and 

 deep. The ridges of the trochlea are practi- 

 cally sagittal in direction and are almost similar. 

 The intercondyloid fossa is wide. Just above 

 each condyle posteriorly there is a facet for 



articulation with the sesamoid (of Vesal), which is developed in the origin of the 

 gastrocnemius muscle. 



The tibia is about the same length as the femur. The shaft forms a double 

 curve ; the upper part is convex internally, the lower part externally. The proximal 

 third is prismatic, but is compressed laterally and is long from before backward. 

 The remainder is almost regularly cylindrical. The crest is short but very prominent. 

 The nutrient foramen is usually in the upper third of the external border. The 

 tuberosity is not grooved, but ])ears a distinct mark where the ligamentum patellse 

 is attached. There is a small facet for the fibula on the postero-external part of 

 the external condyle, and a small sesamoid bone in the tendon of origin of the 

 popliteus is in contact with the posterior angle of the latter. The distal end is 

 quadrangular and relatively small. The articular grooves and ridge are almost 

 sagittal. There is a facet externally for articulation with the fibula. There is a 

 vertical groove internally and a shallower one behind — both for tendons. 



Fig. 137. — Skeleton of Distai- Part of 

 Pelvic Limb of Dog, External View. 

 6, Tibial tarsal bone; 7, fibular tarsal; 

 <9, central tarsal; 9, second tarsal; 10, third 

 tarsal; 11, fourth tarsal; 13, metatarsal 

 bones; 13, first phalanx. The first tarsal 

 bone is not visible in the figure. (After 

 Leisering's Atlas.) 



