Main Vessels in the Pelvis
The internal iliac artery supplies blood to the pelvic wall and the pelvic organs. The sacral median artery courses over the ventral surface of the sacrum and continues as the median caudal artery in the tail.
The internal iliac artery divides into the caudal gluteal artery (wide) and internal pudendal artery (smaller), after detaching the umbilical artery. In the mature dog and cat internal iliac artery gives off branches to the bladder, after which it becomes the ligament in the cranial edge of the lateral bladder ligament. The internal pudendal artery courses at the inside of the pelvic wall and branches off the prostatic artery or the vaginal artery, which continues cranially as the uterine artery. Internal pudendal artery also detaches branches to the rectum, bladder, and urethra. Near the anus the internal pudendal artery detaches the ventral perineal artery before continuing as the artery of the penis or clitoris.Comprehension Check
1. Relate the topography of the pelvic viscera observed in a cadaver to the two-dimensional radiographic and ultrasonographic images.
2. Develop a flow chart of the branches of the internal iliac artery and the specific areas of the urogenital tract they supply. Describe the changes in the vascular supply necessitated by the pregnancy.
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* In addition to marking, ostentatious cocking of the leg by a male dog when passing urine may assert superiority. Cats also make a social use of micturition (see later).
* Ovulation is not spontaneous in the cat; it is induced by coitus.
* Successful service may precede or follow ovulation by an interval of several days, and gestation measured from the date of service consequently has the inconveniently wide range of 58 to 68 days. The practice—generally unavoidable—of measuring gestation in days after service explains the difficulty of precisely specifying the period of change in the form of the uterus or of specific development of the fetus. Prediction of the date of parturition in days subsequent to the appearance of certain features of skeletal mineralization is more exact.
* Queens also sometimes spray, though generally they squat when passing urine, which they then seek to conceal by scratching dirt over it. It seems that spraying by females is most often performed far from home, at the bounds of a territory disputed with other cats; it is, in consequence, less commonly objectionable to the householder. In both sexes, the practice may have sexual connotations.
* It is also claimed that female kittens can be spayed at the same early age without unacceptably greater risk. Humane societies tend to be the strongest advocates of early neutering, before kittens are adopted by their permanent owners, because it avoids unwanted pregnancies with the inevitable consequence of abandoned animals' contributing to feral populations.