The abdominal cavity of the ox is very capacious, both absolutely and
relatively, as compared with that of the horse. This is due to several
factors. The lumbar portion of the spine is about one-fourth longer than
that of the horse. The transverse diameter between the last ribs is
greater. The costal attachment of the diaphragm is almost vertical in
direction from the lower part of the ninth rib to the extreme upper part
of the thirteenth; in fact, the attachment to the last rib is not
constant. Thus the abdomen is increased at the expense of the thorax,
and the last three or four ribs enter more largely into the formation of
the abdominal wall than in the horse. The flank is also much more
extensive. The ilia, on the other hand, do not extend forward beyond a
transverse plane through the middle of the last lumbar vertebra. The
epigastric and mesogastric regions would be separated by a plane through
the lower end of the tenth pair of ribs, or through the last thoracic
vertebra. The chief differential features in the arrangement of the
peritoneum will be described with the viscera.