214 ANATOMY IN A NUTSHELL. 



(3) The inferior gluteal nerve is derived from the fifth lumbar, first 

 and second sacral nerves. It leaves the pelvis below the Pyriformis muscle 

 with the sciatic and pudic vessels and nerves. It gives muscular branches to 

 the ( Huteus maximus. 



(4) The nerve to the Quadratus femoris is derived from the fourth, fifth 

 lumbar, and first sacral nerves. It leaves the pelvis below the Pyriformis 

 muscle. It sends a branch to the Gemellus inferior, and also one to the hip- 

 joint. 



i.")i The nerve i<» the Obturator interims is derived from the fifth lumbar, 

 tirst and second sacral nerves. It leaves the pelvis below the Pyriformis mus- 

 cle and re-enters the pelvis through the lesser sacrc -sciatic foramen to be dis- 

 tributed to the inner surface of this muscle. It gives a branch to the Gemellus 

 superior. 



Under ((') cutaneous branches we have, (Plate LXXYIII.) 



(1) The small sciatic is derived from the first, second, and third sacral 

 nerves. It leaves the pelvis through the great sacro-sciatic foramen below the 

 Pyriformis muscle with the sciatic vessels and the great sciatic nerve, inferior 

 gluteal nerve, internal pudic nerve and vessels. At the lower border of the 

 Glutens maximus it passes behind the long head of the Biceps and descends 

 beneath the deep fascia to the popliteal space. Some say it supplies the Gluteus 

 maximus, bu1 outside of supplying this one muscle it is cutaneous. Its branches 

 are first; peroneal cutaneous which supplies the skin of the upper, inner, and 

 posterior aspects of the thigh and perineum. One of these branches, the in- 

 ferior or long pudendal nerve, crosses the tuberosity of the ischium and per- 

 forates the fascia lata and Colles' fascia to enter the anterior compartment of 

 the perineum. In the perineum it communicates with the superficial perineal 

 nerves and sends branches to the skin of the scrotum in the male, and to the 

 major lip in the female. Second; Femoral cutaneous branch which supplies 

 the integumenl on the central, inner and outer aspects of the posterior partof 

 the thigh. Third; Gluteal or ascending cutaneous branches to supply the skin 

 over the lower and outer part of the Gluteus maximus. 



(2) Perforating cutaneous nerve is derived from the second and third sacral 

 nerves. It perforates the greater sacro-sciatic ligament and supplies the skin 

 over the lower and inner part of the Gluteus maximus. 



Under I D) terminal branches we have. 



(1) The pudic nerve is derived from the second, third and fourth sacral 

 nerves. It haves the pelvis below the Pyrifomis muscle. It now crosses the 

 spine of the ischium, being on the inner side of the internal pudic artery, which 

 it accompanies through the lesser sacro-sciatic notch into Alcock's canal where 

 it divides into three branches. First; the inferior hemorrhoidal nerve which 

 passes through the inner wall of Alcock's canal towards the anus to supply the 

 sphincter ani and the adjacent integument. Second; the perineal branch 

 which has a cutaneous branch called the superficial perineal. It leaves Alcock's 

 canal ami pierces the base of the triangular ligament and is distributed to the 

 skin of the scrotum in the mule or the major lip in the female. Third; the dor- 

 sal nerve of the penis, pierces the posterior layer of the triangular ligament and 





