500 



THE INFERIOR EXTREMITY 



The Common Peroneal Nerve (L. 4, 5, S. i and 2) may be 

 injured in fractures of the neck of the fibula, in scythe wounds 

 and during forcible movements of the ankylosed knee-joint. 



The muscles of the anterior and lateral compartments of the 

 leg are paralysed and the foot, therefore, adopts the attitude 

 of talipes equino-varus (p. 495). 



L!V 



, Lumbo-sacral trunk 



Superior gluteal nerve 



Inferior gluteal nerve 



To piriformis I 



To piriformi 



Nerve to quadratus femoris 

 Nerve to obturator internus 



Sciatic nerv 



Common 

 peroneal nerve 



Sciatic nerve 



\ Tibial nerve 



Post. cut. N. of thigh (O.T. small sciatic) 

 Perineal N. and dorsal N. of penis | Pudend: 

 Inferior haemorrhoidal nerve / nerve 



'-Perforating cutaneous nerve 



Nerves to levator ani 

 Coccygeal branches 



FIG. 148. Diagram of the Sacral Plexus. 



When the nerve is injured, proximal to the point of origin of 

 its lateral cutaneous branch (p. 446), alterations in sensibility 

 are found over the dorsum of the foot and the lateral and anterior 

 aspects of the leg, but, when the injury occurs distal to that point, 

 the sensory disturbance is confined to the dorsum of the foot. 



The Tibial Nerve (L. 4 and 5, S. i, 2, and 3) is rarely injured, 

 but when it is completely divided, all the muscles of the sole of 

 the foot and of the posterior compartment of the leg are paralysed. 



