PELVIS MINOR 463 



In addition to the two main bands into which the sacral 

 andptidendal plexuses resolve themselves (sciatic and pudendal) 

 various other branches are given off, some from the back and 

 some from the front of the plexus. They are : 



1. Superior gluteal. 



2. Inferior gluteal. 



3. Posterior cutaneous of the thigh (O.T. small sciatic). 



4. Nerve to the obturator internus and superior gemellus. 



5. Nerve to the quadratus femoris and inferior gemellus. 



6. Perforating cutaneous nerve. 



7. Branches to the piriformis muscle. 



8. Branches to the pelvic viscera. 



Nervns Glutseus Superior. The superior gluteal nerve 

 arises from the posterior aspect of the plexus and contains 

 fibres of the fourth and fifth lumbar and first sacral 

 nerves. It passes, with the superior gluteal vessels, above 

 the upper border of the piriformis muscle, and leaves 

 the pelvis through the upper part of the greater sciatic 

 foramen. It is distributed, in the gluteal region, to the 

 glutaeus medius and glutaeus minimus, and to the tensor fasciae 

 latae muscles. 



Nervus Glutseus Inferior. The inferior gluteal nerve is 

 the special branch of supply to the glutaeus maximus. It also 

 springs from the back of the plexus ; and it contains fibres 

 of the fifth lumbar and the first and second sacral nerves. 

 It passes below the piriformis and through the greater sciatic 

 foramen into the buttock. 



Nervus Cutaneus Femoris Posterior (O.T. Small Sciatic). 

 The posterior cutaneous nerve arises from the back of the 

 plexus and contains fibres of the second and third sacral nerves. 

 It passes between the piriformis and coccygeus, and leaves the 

 pelvis through the lower part of the greater sciatic foramen. 



The Nerve to the Obturator Internus springs from the 

 anterior aspect of the plexus, and contains fibres of the fifth 

 lumbar and the first and second sacral nerves. It leaves the 

 pelvis with the pudendal nerve, and, after giving a twig to the 

 superior gemellus in the gluteal region, it reaches the obturator 

 internus by passing through the lesser sciatic foramen. It 

 sinks into the medial aspect of the muscle. 



The Nerve to the Quadratus Femoris springs from the 

 anterior aspect of the plexus, receiving fibres from the fourth 

 and fifth lumbar and the first sacral nerves. It accompanies 

 the sciatic trunk out of the pelvis, and supplies not only 



