DISSECTION OF THE PELVIS. 363 



(Plate 16) ; the latter continues the direction of the lateral sacral artery 

 to the tail. The inferior division of the 3rd sacral nerve appears in 

 the angle of separation between these two arteries. The collateral 

 branches of the lateral sacral artery are : (1) Branches entering the inter- 

 vertebral foramen between the last lumbar vertebra and the sacrum 

 (last lumbar artery), and the first two or three inferior sacral foramina. 

 Each of these enters the spinal canal, furnishes there a spinal branch, 

 and then emerges by the corresponding superior foramen, and is dis- 

 tributed to the overlying muscles and skin. (2) The middle coccygeal 

 artery is an unpaired vessel, variable as to its origin, but generally, as 

 in Plate 48, furnished by the right lateral sacral artery. It passes 

 inwards to the middle line, and is continued backwards to the tail. 



4. The Ilio- lumbar Artery. This artery is in series with the 

 lumbar arteries, representing, as it were, the abdominal or inferior 

 branch of the last lumbar artery. Arising from the outer side of the 

 parent trunk, it passes outwards across the sacro-iliac joint, giving 

 branches to the iliacus and psoas magnus muscles. Its terminal 

 twigs may reach the gluteus maximus or the tensor vaginae femoris. 



5. The Gluteal Artery, a large vessel, arises at the edge of the 

 sacrum, and passes out into the hip by the great sacro-sciatic foramen, 

 dividing into a number of branches as it escapes (Plate 16). 



The Iliaco-femoral Artery, one of the terminal branches of the 

 internal iliac, passes downwards and outwards beneath the shaft of 

 the ilium and the iliacus muscles, to reach the outer aspect of the 

 thigh. It supplies the nutrient artery of the ilium. 



The Obturator Artery, the other terminal branch of the internal 

 iliac, passes downwards and backwards on the pelvic surface of the 

 ilium, at the anterior edge of the pyriformis muscle. Under cover 

 of the obturator internus muscle, it passes through the obturator 

 foramen and reaches the thigh. It is accompanied by a satellite 

 vein, and by the obturator nerve, which is placed anterior to the 

 vessels. The tendon of the psoas parvus muscle is inserted in the 

 angle of separation between this and the preceding artery. 



The Internal Iliac Vein collects the blood from the satellite veins 

 of the foregoing arteries. It unites with the external iliac vein, 

 forming the common iliac vein. 



The Obturator Internus and the Pyriformis. For a description 

 of these muscles turn to page 69. 



reproductive organs in the female. 



Comprised under this heading there are : the ovaries, the Fallopian 

 tubes, the uterus, the vagina, and the vulva. The ovaries, the Fallopian 

 tubes, and the uterus (in part) are abdominal organs, and their mode of 



