CONFORMATION AND SURFACE ANATOMY
The cranial boundary of the accessible abdominal wall is easily determined by palpation of the last rib and costal arch, but the caudal boundary is more difficult to discover because only the ventral part (pecten ossis pubis) of the bony ring about the pelvic inlet can be palpated between the thighs.
The wings of the ilia, though prominent landmarks, rise above the level of the abdomen and pertain to the back. The thick muscles above the lumbar transverse processes are palpable but not the processes themselves; however, the tips of the spinous processes provide a guide to the identification of individual vertebrae.The abdominal cavity is of course larger than these landmarks appear to indicate because the diaphragm bulges far into the rib cage at its cranial end. The organs in this intrathoracic part of the abdomen are protected by the ribs and are in part overlain by the caudal lobes of the lungs. The abdominal cavity is relatively less voluminous than in the large domestic species and has, by and large, the shape of a cone with a bulbous cranial base (Figure 14-1). Its longitudinal axis inclines cranio- ventrally at an angle that varies considerably; it is steepest in deep-chested breeds. Except in fat subjects and heavily pregnant or lactating bitches, the ventral abdominal wall rises from the sternum to the pecten in a straight or even slightly concave line. Dog fanciers use the expression “tucked-up” to describe animals with an especially shallow body depth at the loin. The skin fold that connects the flank with the stifle tends to obscure the shallowness of this part. Advancing pregnancy enlarges the abdomen in both depth and breadth and gives it a more cylindrical or even a barrel shape.
Superficial inguinal lymph nodes may be palpated in the groin, lateral to the bulbus glandis of the penis or in a comparable site in the bitch (Figure 14-2, B/d).