1062 THE NERVE SYSTEM 



space; the other and larger digital branch supplies the adjoining sides of the fourth 

 and fifth toes, and communicates with the internal plantar nerve. 



The deep or muscular branch (ramus profundus) accompanies the external plantar 

 artery into the deep part of the sole of the foot, beneath the tendons of the Flexor 

 muscles, and Adductor obliquus hallucis, and supplies all the Interossei (except 

 those in the fourth metatarsal space), the three outer Lumbricales, the Adductor 

 obliquus hallucis, and the Adductor transversus hallucis. 



The External Popliteal or Peroneal Nerve (n. peronaeus communis) (Figs. 774 

 and 776), about one-half the size of the internal popliteal, is derived from the 

 posterior branches of the last two lumbar and first two sacral nerves. It descends 

 obliquely along the outer sides of the popliteal space to the head of the fibula, 

 close to the inner margin of the Biceps muscle. It is easily felt beneath the skin 

 behind the head of the fibula at the inner side of the tendon of the Biceps. It 

 passes between the tendon of the Biceps and outer head of the Gastrocnemius, 

 winds around the neck of the fibula, between the Peroneus longus and the bone, 

 and divides beneath the muscle into the anterior tibial and musculocutaneous 

 nerves. 



The branches of the external popliteal nerve, previous to its division, are articular 

 and cutaneous. 



The articular branches (rami articulares) are three in number: two of these 

 accompany the superior and inferior external articular arteries to the outer side 

 of the knee. The upper one occasionally arises from the great sciatic nerve 

 before its bifurcation. The third {recurrent} articular nerve is given off at the 

 point of division of the external popliteal nerve; it ascends with the anterior 

 recurrent tibial artery through the Tibialis anticus muscle to the front of the knee, 

 which it supplies. 



The Lateral Cutaneous Branch (11. cutaneous surae lateralis]. There may be 

 two or three of these branches. They supply the integument along the back 

 part and outer side of the leg. The largest cutaneous branch of the peroneal 

 is the peroneal communicating (ramus anastomoticus peronaeus or communicans 

 fibularis), which arises near the head of the fibula, crosses the external head of the 

 Gastrocnemius to the middle of the leg, and joins with the communicans tibialis 

 to form the external saphenous nerve. This nerve occasionally exists as a sepa- 

 rate branch, which is continued as far down as the heel. 



The Anterior Tibial Nerve or Deep Peroneal (n. peronaeus profundus) (Fig. 771) 

 commences at the bifurcation of the peroneal nerve, between the fibula and upper 

 part of the Peroneus longus, passes obliquely downward beneath the Extensor 

 longus digitorum muscle to the fore part of the interosseous membrane, and 

 gets into relation with the anterior tibial artery above the middle of the leg; 

 it then descends with the artery to the front of the ankle-joint, where it divides 

 into an external and an internal branch. This nerve lies at first on the outer side 

 of the anterior tibial artery, then in front of it, and again at its outer side at the 

 ankle-joint. 



The branches of the anterior tibial nerve in its course through the leg are the 

 muscular branches (rami musculares) to the Tibialis anticus, Extensor longus 

 digitorum, Peroneus tertius, and Extensor proprius hallucis muscles, and an 

 articular branch to the ankle-joint. 



The external or tarsal branch of the anterior tibial nerve passes outward across the 

 tarsus, beneath the Extensor brevis digitorum, and, having become enlarged 

 like the posterior interosseous nerve at the wrist, supplies the Extensor brevis 

 digitorum muscle. From the enlargement three minute interosseous branches 

 are given off which supply the tarsal joints and the metatarsophalangeal joints 

 of the second, third, and fourth toes. The first of these sends a filament to the 

 Second dorsal interosseous muscle. 



