The arterial supply of the urinary bladder.

(1) The urachal artery has a primary origin from the umbilical artery itself, and is at first bilateral. (2) The arterial pattern in newborn infants is not identical to that of adults. Obliteration of the umbilical artery in older infants carries with it obliteration of some of its branches, especially at their origin from its distal part, with a resulting change in arterial pattern. (3) The middle vesicle artery is a fairly constant branch of the umbilical artery, supplying the bladder neck and the front of the bladder above the neck. (4) The urachal and middle vesicle arteries, when unilateral, occur with equal frequency on both sides. (5) The anastomosis between superior vesical and inferior episgastric arteries was confirmed in the subperitoneal tissues, but was very rare in the wall of the bladder, occurring only when an abnormal obturator artery was the source of a superior vesical branch. (6) The constancy of the vesiculo-deferential artery is confirmed.