PHRENIC AND LUMBAR. 42T 



ureter, the vein being usually in front, the ureter behind. Each vessel gives off 

 some small branches to the supra-renal capsules, the ureter, and to the surround- 

 ing cellular membrane and muscles. 



SPERMATIC ARTERIES. 



The Spermatic Arteries are distributed to the testes in the male, and to the 

 ovaria in the female. They are two slender vessels, of considerable length, 

 which arise from the front of the aorta, a little below the renal arteries. Each 

 artery passes obliquely outwards and downwards, behind the peritoneum, cross- 

 ing the ureter, and resting on the Psoas muscle, the right spermatic lying in 

 front of the inferior vena cava, the left behind the sigmoid flexure of the colon. 

 On reaching the margin of the pelvis, each vessel passes in front of the 

 corresponding external iliac artery, and takes a different course in the two sexes. 



In the male, it is directed outwards, to the internal abdominal ring, and 

 accompanies the other constituents of the spermatic cord along the spermatic 

 canal to the testis, where it becomes tortuous, and divides into several branches, 

 two or three of which accompany the vas deferens, and supply the epididymis, 

 anastomosing with the artery of the vas deferens ; others pierce the back part of 

 the tunica albuginea, and supply the substance of the testis. 



At an early period of fcetal life, when the testes lie by the side of the spine, 

 below the kidneys, the spermatic arteries are short ; but as these organs descend 

 from the abdomen into the scrotum, they become gradually lengthened. 



In the female, the spermatic arteries (ovarian) are shorter than in the male, 

 and do not pass out of the abdominal cavity. On arriving at the margins of the 

 pelvis, each artery passes inwards, between the two laminae of the broad ligament 

 of the uterus, to be distributed to the ovary. One or two small branches supply 

 the Fallopian tube ; another passes on to the side of the uterus, and anastomoses 

 with the uterine arteries. Other offsets are continued along the round ligament, 

 through the inguinal canal, to the integument of the labium and groin. 



PHRENIC ARTERIES. 



The Phrenic Arteries are two small vessels, which present much variety in their 

 origin. They may arise separately from the front of the aorta, immediately below 

 the cceliac axis, or by a common trunk, which may spring either from the aorta, or 

 from the coeliac axis. Sometimes one is derived from the aorta, and the other from 

 one of the renal arteries. In only one out of thirty-six cases, did these arteries 

 arise as two separate vessels from the aorta. They diverge from one another 

 across the crura of the Diaphragm, and then pass obliquely upwards and outwards 

 upon its under surface. The left phrenic passes behind the oesophagus, and runs 

 forwards on the left side of the cesophageal opening. The right phrenic passes 

 behind the liver and inferior vena cava, and ascends along the right side of the 

 aperture for transmitting that vein. Near the back part of the central tendon, 

 each vessel divides into two branches. The internal branch runs forwards to the 

 front of the thorax, supplying the Diaphragm, and anastomosing with its fellow 

 of the opposite side, and with the musculo-phrenic, a branch of the internal 

 mammary. The external branch passes towards the side of the thorax, and in- 

 osculates with the intercostal arteries. The internal branch of the right phrenic 

 gives off a few vessels to the inferior vena cava; and the left one some branches 

 to the oesophagus. Each vessel also sends capsular branches to the supra-renal 

 capsule of its own side. The spleen on the left side, and the liver on the right, 

 also receive a few branches from these vessels. 



LUMBAR ARTERIES. 



The Lumbar Arteries are analogous to the intercostal. They are usually four 

 in number on each side, and arise from the back part of the aorta, nearly at right 

 angles with that vessel. They pass outwards and backwards, around the sides of 



