622 NERVES OF THE LOWER LIMB. 



The nerve first reaches the outer side of the anterior tibial artery, 

 above the middle of the leg ; and, after crossing in front of that vessel 

 once or oftener, lies to the outer side of it at the bend of the ankle. 



(a) 2Iuscula)' hranchcs. — In its course along the leg, tlie anterior tibial nerve 

 gives slender filaments to tlie muscles between whicli it is placed, namely, the 

 tibialis anticus, the long extensor of the toes, and the special extensor of the 

 great toe. 



(h) The external hrancli of the anterior tibial nerve turns outwards over the 

 tarsus beneath the 'short extensor of the toes ; and, having become enlarged (like 

 the posterior mterosseous nerve on the wrist) tenninates in branches which 

 supply the short extensor muscle, and likewise the articulations of the foot. 



(<■) The internal hranch, continuing onwards in the direction of the anterior 

 tibial nerve, accompanies the dorsal artery of the foot to the first interosseous 

 space, and ends in two branches, which supply the integument on the neighljouring 

 sides of the great toe and the second toe on their dorsal aspect. It commimi- 

 cates with the internal division of the musculo-cutaneous nerve. 



Summary of the External Popliteal Nerve. — This nerve sup- 

 plies, besides articular branches to the knee, ankle, and foot, the peronei 

 muscles, extensor muscles of the foot, also the integument of the front 

 of the leg and dorsum of the foot. It gives the ramus communicans 

 fibularis to the short saphenous branch of the internal popliteal nerve, 

 and communicates with the long saphenous nerve. 



SYNOPSIS OF THE CUTANEOUS DISTRIBUTION OF 

 THE CEEEBRO-SPINAL NERVES. 



1. In tlie Head. — The face and licadin front of the ear are supplied 

 with sensory nerves from the fifth cranial nerve. The ophthalmic 

 division supplies branches to the forehead, upper eyelid, and dorsum of 

 the nose. The superior maxillary division supplies the cheek, ala of the 

 nose, upper lip, lower eyelid, and the region behind the eye, over the 

 temporal fascia. The inferior maxillary division supplies the chin and 

 lower lip, the pinna of the ear on its outer side, and the integument 

 in front of the ear and upwards to the vertex of the head. 



The head, hehind the ear, is mainly supplied by the great occipital 

 branch of the posterior division of the second sjiinal nerve, but above 

 the occipital protuberance there is also distributed the branch from the 

 posterior division of the third spinal nerve ; and, in front of the area of 

 the great occipital nerve, is a space supplied by anterior divisions of 

 spinal nerves, viz., the back of the pinna of the ear, together with the 

 integument behind and that in front over the parotid gland, which are 

 supplied by the great auricular nerve ; while between the area of that 

 nerve and the great occipital the small occipital nerve intervenes. The 

 auricular branch of the pneumo-gastric nerve also is distributed on the 

 back of the ear. 



2. In the Trunk. — The posterior divisions of tlie spinal nerves supply 

 an area extending on the back from the vertex of the skull to the buttock. 

 This area is narrow in the neck ; it is spread out over the back of the 

 scapula ; and on the buttock the distribution of the lumbar nerves 

 extends to the trochanters. 



The area supplied bij the cervical plexus, besides extending upwards, as 

 already mentioned; on the lateral part of the skull, stretches over the 



