DISSECTION OP 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 

 intervertebral foramen between the last lumbar vertebra and the sacrum 

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

 Each of these entei-s 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 



