THE SACRAL PLEXUS 



181 



AFFECTIONS OF THE SCIATIC NERVE or of its numerous 

 branches are by no means uncommon. The main trunk is pro- 



FIG. 74. The Nerve-supply of the Skin on the Posterior Aspect 

 of the Lower Limb. 



A. The individual nerves of supply. 



B. The segmental supply. 



1. Posterior rami of L. i, 2 and 3. 



2. Posterior rami of S. 1,2 and 3. 



3. Sacro-coccygeal nerve. 



4. Iliac branch of ilio-hypogastric nerve. 



5. Posterior cutaneous nerve of thigh 



(small sciatic nerve). 



6. Lateral cutaneous nerve of thigh. 



7. Lateral sural nerve. 



8. Nervus suralis. 



9. Saphenous nerve. 



10. Medial cutaneous nerve of thigh. 



11. Obturator nerve. 



vided with a thick, fibrous sheath, which is the site of inflamma- 



