The =os coxæ= is long and narrow. The ilium and ischium are almost in
line with each other and sagittal in direction. The wing of the =ilium=
bends outward much less than in the horse or ox. The gluteal surface is
divided into two fossæ by a ridge, which is continuous with the superior
ischiatic spine behind. The inner surface presents an extensive rough
area behind, which is in apposition with the wing of the sacrum. The
smooth iliac area is narrow, and is bounded above by a ridge. The crest
or anterior border is convex, and is thick, rough, and prominent in its
middle, which forms the highest point of the bone. The internal angle is
lower than the crest, is directed backward, and articulates internally
with the sacrum. The external angle is lower still and is very little
thickened. The =ischia= in the female are somewhat divergent and
flattened behind. The tubera are everted and bear three prominences.
There is a crest or tuberosity on the ventral surface. The superior
ischiatic spine is like that of the cow, but is slightly incurved and
the muscular ridges on its outer face are more pronounced. The
symphyseal part of the =pubis= is thick and the two bones are almost in
a horizontal plane. The ilio-pectineal eminence is prominent and the
psoas tubercle is well marked.
The =acetabulum= is placed a little further back than in the ox. The rim
is thick and is cut into posteriorly by a narrow fissure, which leads
into the deep fossa acetabuli. The three pieces of the os coxæ are fused
by the end of the first year, but the crest and the ischial tubera are
partially separate till the sixth or seventh year. The symphysis does
not usually undergo complete anchylosis. Interischial bones are present.
The =inlet= of the =pelvis= is elliptical and very oblique. In a sow of
full size the conjugate diameter is about five to six inches (10 to 12
cm.) and the transverse about three and a half to four inches (ca. 8.75
to 10 cm.). In the female the floor is relatively wide and flattened,
especially at the outlet, where the tubera are everted; it also has a
decided downward inclination behind. The pelvic axis is therefore
correspondingly oblique. The ischial arch is wide. In the boar the pubis
is much thicker and the ischia are not everted posteriorly. The inlet is
smaller. The floor is concave from side to side and slopes decidedly
less than in the sow. The superior ischiatic spines are more incurved,
and the ischial arch is much narrower and deeper.
The =femur= has a relatively wide and massive shaft, on which four
surfaces might be recognized. The principal nutrient foramen is situated
in the proximal third of the anterior surface. The posterior surface is
wide, and is limited outwardly by a ridge which extends from the
trochanter major to the large external supracondyloid crest. There is no
supracondyloid (plantar) fossa. The head is strongly curved, and is
marked toward the inner side by a rather large depression for the
attachment of the round ligament. The neck is distinct. The trochanter
major, although massive, does not extend up as high as the head. The
trochanteric ridge and fossa resemble those of the ox. The external
(third) trochanter is absent. The ridges of the trochlea are similar and
almost sagittal.
The shaft of the =tibia= is slightly curved, convex internally. The
tuberosity is grooved in front, and a narrow sulcus separates it from
the external condyle. The facet for the fibula is on the posterior
border of the latter, and is bounded internally by an eminence. The
upper part of the crest is very prominent and curves outward. The distal
end resembles in general that of the ox, but is relatively narrower
transversely and thicker from before backward.
The =fibula= extends the entire length of the region, and is separated
from the tibia by a wide interosseous space. The shaft is flattened from
side to side; the proximal part is wide and deeply grooved externally;
the lower part is narrower and thicker. The proximal end is flattened,
grooved externally, and articulates internally with the external condyle
of the tibia. The distal end forms the external malleolus. It is grooved
externally, and articulates with the tibia and tibial tarsal internally,
with the fibular tarsal bone distally.
The =patella= is very much compressed laterally and presents three
surfaces.
[Illustration: