THE SACRAL PLEXUS 373 



also the interossei of the fourth space, and another digital 

 branch to the adjacent sides of this toe and the fourth. 



The deep branch dips under the accessorius and flexor muscles, 

 and supplies all the dorsal and plantar interossei except, occa- 

 sionally, those of the fourth space; it also supplies the outer 

 two lumbricales, the adductor pollicis, and the transversns 

 pedis. 



The external popliteal or peroneal nerve runs between the 

 biceps muscle and outer head of the gastrocnemius, turns 

 round the fibula just below its head and beneath the peroneus 

 longus, and divides into the anterior tibial and the musculo- 

 cutaneous nerves. 



Branches. Articular, with the upper and lower external 

 articular arteries, and occasionally a recurrent articular branch, 

 with the recurrent tibial artery, reaches the joint. 



Cutaneous, two in number, supply the skin of the outer and 

 back part of the leg; and another, arising from its lower part, 

 the peroneal communicating, crosses the outer head of the 

 gastrocnemius and passing obliquely downward joins the 

 popliteal communicating to form the short saphenous nerve. 



The musculocutaneous nerve runs between the extensor 

 longus digitorum and the peronei, and pierces the fascia at 

 the lower part of the leg, dividing into two branches, external 

 and internal, for the toes. 



Branches. Muscular, to the peroneus longus and brevis; 

 cutaneous, to the lower part of the leg. 



The terminal branches: . Of these, the internal runs on the 

 dorsum of the foot and supplies the adjacent sides of the second 

 and third toes and the inner side of the great toe. It com- 

 municates with the long saphenous and anterior tibial nerves. 



The external supplies the fourth toe, together with the con- 

 tiguous sides of the third and fifth. It communicates with 

 a branch of the short saphenous nerve. 



The anterior tibial nerve, from between the peroneus longus 

 and fibula, runs along the front of the interosseous membrane 

 with the artery to the ankle, where it divides into an external 

 and an internal branch. It is at first external, then in front, 

 and below again external to the artery. 



Branches. Muscular, to the tibialis anticus, extensor longus 

 digitorum, extensor proprius, and the peroneus tertius; artic- 

 ular, to ankle; and its terminal branches. Of these 



