174 ANATOMY IN A NUTSHELL. 



Pyriformis muscle, lying between this muscle and the Cuccygeus. After cross- 

 ing the spine of the ischium, external to the nerve, it passes through the lesser 

 sacro-sciatic foramen into the pelvis, it now passes through Aleock's canal 

 about an inch and a half above the tuberosity of the ischium, it now pierces the 

 triangular ligament where it divides into the dorsal artery of the penis and the 

 artery of the corpus cavernosum. Besides these two terminal branches it has 

 the (1) muscular, (2) inferior hemorrhoidal. (3) superficial perineal, (4) trans- 

 perineal, (5) artery of the bulb. The sciatic branch is the larger of the 

 terminal branches of the anterior trunk and passes through the great sacro- 

 sciatic foramen below the Pyriformis, then descends between the tuberosity of 

 the ischium and the trochanter of the femur under the Gluteus maximus, and 

 then helps to form the crucial anastomosis which is made by four branches, the 

 first three of which are branches of the profunda artery and the fourth is the 

 S< [atii BRANCH. The first three branches are named internal circumflex, 

 external circumflex, and superior perforating. Inside the pelvis the 

 sciatic artery gives branches to the rectum, neck and base of bladder, prostate 

 gland, and muscle- of the floor of the pelvis. Outside the pelvis the sciatic 

 artery gives anastomotic and coccygeal branches, which run through the great 

 sacro-sciatic ligament to the back of the coccyx, and inferior gluteal branches 

 (which are three or four) to the Gluteus maximus. and muscular branches to 

 the muscles on the back of the hip. It sends articular branches to the hip-joint 

 and comes nekyi ischiadici to the great sciatic nerve. The uterine branch 

 runs to the cervix of the uterus and then along its sides in the broad ligament 

 to anastomose with the ovarian. This artery is above and in front of the ureter. 



The Relations of the Common Iliac Arteries. (Plates LXXII-XCI.) The 

 right common iliac artery has the following relations: 



In Front. — (1) Peritoneum, (2) Small intestine, (3) Sympathetic nerves, 

 and (4) Ureter. 



Behind.— (1) Fourth and fifth lumbar vertebrae, (2) Right common iliac 

 vein, (3) Lef1 common iliac vein. 



Outer Side. — (1) Vena cava. (2) Right common iliac vein, (3) Psoas 

 muscle. 



Inner Side.— (1) Left common iliac vein. 



The Left Common Iliac Artery has the following relations: 



I\ Front.- (1) Peritoneum, (2) Small intestine, (3) Sympathetic nerves, 

 I Superior hemorrhoidal artery. (5) Ureter. 



Behind." (1) Fourth and fifth lumbar vertebra?, (2) Left common iliac 

 vein. 



( >i m.i; Side. — Psoas magnus muscle. 



Iwi.i; Side. Left common iliac vein. 



The Relations of the Internal Iliac Artery.— (Plates LXXII-XCT.) 



In Front. — (1) Peritoneum, and (2) Ureter. 



Behind. — (1) Interna] iliac vein, (2) Lumbo-sacral cord. (3) Pyriformis 

 muscle. 



( )ii i;i; Side.— Psoas magnus. 



The Relations of the External Iliac Artery. (Plate XCI.) 



