418 SPECIAL ANATOMY. 



b. Nn. scrotales s. labiaks are reflected beneath the m. glutceus 

 maximus inwards, and terminate in the skin of the internal 

 superior part of the scrotum or labia maj., sometimes also in 

 the perinceum. 



c. Nn. cutanei femoris posteriores, for the skin of the posterior 

 and inner part of the thigh as far as the posterior and outer 

 part of the popliteal region, whence filaments extend down- 

 wards to the outer and interior region of the calf. 



4. N. pudendus s. spermaticus communis arises (variably) from 

 the flat cord of the associated sacral nerves, immediately passes in 

 the depth between lig. spinoso-sacrum and sacro-ischiadicum on 

 the inner side of art. pudenda under m. levator ani, and divides 

 into : 



a. Ram. inferior s. 2V. perincci, corresponds to the art. pudenda 

 (with the exception of art. dorsalis penis), passes, above this, 

 from behind forwards, then between m. obturator intern, and 

 membr. obturat. with a curve upwards, and terminates with a 

 superficial branch (with art. transv. perin.), taking a course, 

 obliquely inwards and forwards, to the lower part of the scro- 

 tum and the penis, with a deep branch to the anterior part of 

 sphincter ani, to the bulbo-cavernos. and bulbus urethra (in 

 the female to sphincter vagina, the labia and mons Veneris). 



b. Ramus superior s. n, dorsalis penis (n. clitoridis of the 

 female), passes in a curve (with art. pudenda), at first close 

 to the inner surface of the tuber ischii, then upwards between 

 levator ani and obturator internus, and beneath symphysis 

 pubis (surrounded by the veins), upon the dorsum of the penis 

 in the middle line, and more superficial than art. dorsalis ; it 

 divides into two branches, the internal deeper of which goes 

 to the glans, the external cutaneous ramifies on the sides of 

 the penis, and forms a plexus which supplies the skin of the 

 three superior fourths of the organ. 



The nerve of the clitoris is finer and smaller, but takes pre- 

 cisely the same course. 



5. 2V. hamorrhoidalis infimus arises, frequently, from n. pu- 

 dendus, passes, more internally than this, between lig. tuberoso- 

 and spinoso-sacrum, under the levator ani, in the fat, divides and 

 passes to the posterior part of the sphincter aniand the neighbouring 

 skin. 



6. 2V. ischiadicus, the largest nerve of the body, arises from the 

 third and fourth lumbar, and the first, second and third sacral 

 nerves, passes out from the incisura ischiadica major below n. 

 pyriformis, flattened, descends between tuber ischii and trochanter 



