734 THE NEEVOUS SYSTEM. 



the peroneal anastomotic ramus extending only to the ankle and heel. It is less usual 

 for the peroneal anastomotic ramus alone to form the nervus suralis, the medial sural 

 nerve in these cases ending at the heel. 



(c) Branches arising in the Back of the Leg distal to the Knee- Joint. These 

 branches are mainly muscular and cutaneous. 



The muscular branches are four in number, comprising nerves to the soleus 

 (entering its deep surface) and tibialis posterior, often arising by a common trunk, 

 and nerves to the flexor digitorum longus and flexor hallucis longus, the latter 

 generally accompanying the peroneal artery for some distance. 



Rami Calcanei Mediales. The cutaneous branches are the medial calcanean 

 rami, which pierce the ligamentum laciniatum, and is distributed to the skin 

 of the heel and posterior part of the sole of .the foot. 



In addition, a medullary nerve to the fibula, and a small articular branch to 

 the ankle-joint, are supplied by the tibial nerve. 



The terminal branches of the tibial nerve are the medial and lateral 

 plantar nerves. 



NERVUS PLANTARIS MEDIALIS. 



The medial plantar nerve is homologous with the median nerve in the hand 

 (Fig. 629, p. 733). It is rather larger than the lateral plantar. It courses 

 forwards in the sole of the foot, under cover of the ligamentum lanciniatum 

 and abductor hallucis, to the interval between that muscle and the flexor digitorum 

 brevis, in company with the medial plantar artery. 



The collateral branches are muscular, cutaneous, and articular. The muscular 

 branches supply the abductor hallucis and the flexor digitorum brevis. The plantar 

 cutaneous branches are small twigs which pierce the plantar aponeurosis in the 

 interval between these muscles to supply the medial part of the sole of the foot. 

 The articular branches are minute twigs which supply the tarsal and tarso- 

 metatarsal articulations. 



Nn. Digitales Plantares Communes. The terminal branches are four in 

 number, the common plantar digital nerves, and. may be designated first, second, 

 third, and fourth, from medial to lateral side. 



The first (most medial) branch separates from the nerve before the others, 

 and pierces the plantar aponeurosis behind the ball of the great toe. It supplies 

 a muscular branch to the flexor hallucis brevis, and cutaneous branches to the 

 medial side of the foot and ball of the great toe. It terminates as the plantar 

 digital nerve for the medial side of the great toe. 



The second branch arises along with the third and fourth; after supplying ai 

 branch to the first lumbrical muscle, it becomes superficial in the interval between 

 the first and second toes, and terminates by dividing into two proper digital 

 nerves for the supply of the adjacent sides of these toes. 



The third and fourth branches are entirely cutaneous in their distribution. They j 

 become superficial in the intervals between the second and third and the third 

 and fourth toes, respectively, and there divide into proper digital branches for 

 the supply of the adjacent sides of these toes. 



Nn. Digitales Plantares Proprii. The plantar proper digital nerves supply 

 the whole length of the toes on the plantar aspect, and, in relation to the terminalj 

 phalanges, 'furnish minute dorsal offsets for the supply of the nails and tips oi| 

 the toes on their dorsal surface. 



The medial plantar nerve thus supplies the skin of the three and a half medial j 

 toes in the sole of the foot; and four muscles: the abductor hallucis and flexor: 

 digitorum brevis, the flexor hallucis brevis, and the first lumbrical muscle. 



NERVUS PLANTARIS LATERALIS. 



The lateral plantar nerve is homologous with the ulnar nerve in the hand 

 From its origin, under cover of the ligamentum laciniatum, it extends forward f 



