THE INTERNAL ILIAC ARTERY 



679 



The sciatic artery (a. glutaca inferior) (Fig. 477), the larger of the two terminal 

 branches of the anterior trunk of the internal iliac, is distributed chiefly on the 

 buttock and back of the thigh. It passes down to the lower part of the great 

 sacrosciatic foramen behind the internal pudic artery, resting on the sacral plexus 

 of nerves and Pyriformis muscle, and escapes from the pelvis through this foramen 

 between the Pyriformis and 

 Coccygeus. It then descends 

 in the interval between the tro- 

 chanter major and tuberosity 

 of the ischium, accompanied 

 by the sciatic nerves, and 

 covered by the Gluteus maxi- 

 mus, and is continued down 

 the back of the thigh supplying 

 the skin, and anastomosing 

 with branches of the perfora- 

 ting arteries. 



Within the pelvis it distrib- 

 utes branches to the Pvriformis, 

 Coccvgeus, and Leva tor ani 

 muscles; some hemorrhoidal 

 branches, which supply the 

 rectum, and occasionallv take 



Termination 

 of internal 

 circumflex. 



the place of the middle hemor- 

 rhoidal artery; and vesical 

 branches to the base and neck 

 of the bladder, seminal vesicles, 

 and prostate gland. Outside 

 the pelvis it gives off the fol- 

 lowing branches: 



Muscular. 



Coccygeal. 



Comes nervi ischiadici. 



Anastomotic. 



Articular. 



Cutaneous. 



The muscular branches sup- 

 ply the Gluteus maximus, 

 anastomosing with the gluteal 

 artery in the substance of the 

 muscle; the External rotators, 

 anastomosing with the internal 

 pudic artery; and the muscles 

 attached to the tuberosity of the 

 ischium, anastomosing with the 

 external branch of the obturator 

 and the internal circumflex 

 arteries. 



The coccygeal branch runs inward, pierces the great sacrosciatic ligament, and 

 supplies the Gluteus maximus, the integument, and other structures on the back 

 of the coccyx. = 



The conies nervi ischiadici (a. comitans n. ischiadici) is a long, slender vessel 

 which accompanies the great sciatic nerve for a short distance; it then penetrates 

 it and runs in its substance to the lower part of the thigh. 



JSuperior 

 perforating. 



Middle 

 perforating. 



Inferior 

 perforating. 



Termination of 

 profunda. 



Superior muscular. 



Superior external 

 articular. 



Inferior muscular 



FIG. 477. The arteries of the gluteal and posterior femoral 

 regions. 



Superior internal 

 articular. 



