586 SPINAL NERVES. 



to the Gemellus inferior and Quadratus femoris also arises from the lower part of 

 the plexus, passes beneath the Gemelli and tendon of the Obturator interirsa 

 and supplies an articular branch to the hip-joint. This branch is occasionally 

 derived from the upper part of the great sciatic nerve. 



The SUPERIOR GLUTEAL NERVE arises from the back part of the lumbo-sacral ; 

 it passes from the pelvis through the great sacro-sciatic foramen above the Pyri- 

 formis muscle, accompanied by the gluteal vessels, and divides into a superior and 

 an inferior branch. 



The superior branch follows the line of origin of the Gluteus minimus, and 

 supplies it and the Gluteus medius. 



The inferior branch crosses obliquely between the Gluteus minimus and Gluteus 

 medius, distributing filaments to both these muscles, and terminates in the Tensor 

 vaginae femoris, extending nearly to its lower end. 



The PUDIC NERVE arises from the lower part of the sacral plexus, and leaves 

 the pelvis, through the great sacro-sciatic foramen, below the Pyriformis. It then 

 crosses the spine of the ischium, and re-enters the pelvis through the lesser sacro- 

 sciatic foramen. It accompanies the pudic vessels upwards and forwards along the 

 outer wall of the ischio-rectal fossa, being covered by the obturator fascia, and 

 divides into two terminal branches, the perineal nerve and the dorsal nerve of the 

 penis. Near its origin, it gives off the inferior hemorrhoidal nerve. 



The inferior hemorrhoidal nerve is occasionally derived from the sacral 

 plexus. It passes across the ischio-rectal fossa, with its accompanying vessels, 

 towards the lower end of the rectum, and is distributed to the External sphincter 

 and the integument round the anus. Branches of this nerve communicate with 

 the inferior pudendal and superficial perineal nerves on the inner margin of the 

 thigh. 



The perineal nerve, the most inferior and largest of the two terminal branches 

 of the pudic, is situated below the pudic artery. It accompanies the superficial 

 perineal artery in the perineum, dividing into cutaneous and muscular branches. 



The cutaneous branches (superficial perineal) are two in number, posterior and 

 anterior. The posterior branch passes to the .back part of the ischio-rectal fossa, 

 distributing filaments to the Sphincter ani and integument in front of the anus, 

 which communicate with the inferior hemorrhoidal nerve; it then passes for- 

 wards, with the anterior branch, to the back of the scrotum, communicating with 

 this nerve and the inferior pudendal. The anterior branch passes to the fore 

 part of the ischio-rectal fossa, in front of the preceding, and accompanies it to the 

 scrotum and under part of the penis. This branch gives one or two filaments to 

 the Levator ani. 



The muscular branches are distributed to the Transversus perinei, Accelerator 

 urinae, Erector penis, and Compressor urethra. The nerve of the bulb supplies 

 the corpus spongiosum ; some of its filaments run for some distance on the surface, 

 before penetrating its interior. 



The dorsal nerve of the penis is the superior division of the pudic nerve ; it 

 accompanies the pudic artery along the ramus of the ischium, and between the 

 two layers of the deep perineal fascia ; it then pierces the suspensory ligament of 

 the penis, and accompanies the arteria dorsalis penis to the glans, to which it js 

 distributed. On the penis, this nerve gives off a cutaneous branch, which runs 

 along the side of the organ; it is joined with branches of the sympathetic, and 

 supplies the integument of the upper surface and sides of the penis and prepuce, 

 giving a large branch to the corpus cavernosum. 



In the female, the pudic nerve is distributed to the parts analogous to those in 

 the male; its superior division terminating in the clitoris, the inferior in the 

 external labia and perineum. 



The SMALL SCIATIC NERVE supplies the integument of the perineum and back 

 part of the thigh and leg, and one muscle, the Gluteus rnaximus. It is usually 

 formed by the union of two branches, which arise from the lower part of the 

 sacral plexus. It issues from the pelvis below the Pyriformis muscle, descends 



