298 INFERIOR EXTREMITY 



Nervus Plantaris Lateralis (O. T. External Plantar Nerve). 

 The lateral plantar nerve corresponds to the ulnar nerve in 

 the palm of the hand. It accompanies the lateral plantar artery 

 and presents the same relations. In the interval between the 

 abductor digiti quinti and the flexor digitorum brevis, opposite 

 the base of the fifth metatarsal bone, it divides into a deep 

 and a superficial part. The deep division follows the plantar 

 arch under cover of the flexor tendons. The superficial 

 division divides into a proper and a common digital branch. 



From the trunk of the lateral plantar nerve proceed two 

 muscular branches, viz. to the quadratus plantse and to the 

 abductor digiti quinti. 



The first or lateral proper digital branch of the superficial 

 part of the lateral plantar nerve goes to the lateral side of 

 the little toe. It also gives muscular twigs to the flexor 

 brevis digiti quinti and the interosseous muscles in the 

 fourth intermetatarsal space. 



The second common digital branch divides into two proper 

 digital branches which supply the adjacent sides of the 

 fourth toe and little toe. It likewise sends a twig of com- 

 munication to the third common digital branch of the 

 medial plantar nerve. 



Dissection. The abductor digiti quinti should be completely detached 

 from its origin, and turned forwards in order that a good display may be 

 obtained of the structures composing the second stratum of the sole. 



Second Layer of Muscles and Tendons. As the tendon 

 of the flexor hallucis longus enters the sole it grooves the 

 under surface of the sustentaculum tali and inclines medially 

 towards the great toe. The tendon of the flexor digitorum 

 longus, on the other hand, inclines laterally to reach the 

 middle of the foot, where it divides into four tendons for 

 the four lateral toes. Moreover, the tendons of these two 

 muscles cross each other in the sole the tendon of the 

 flexor digitorum lying upon the plantar or superficial surface 

 of the tendon of the flexor hallucis longus, and receiving from 

 it a strong tendinous slip. 



Sir William Turner has called attention to the fact that this slip, which 

 passes from the tendon of the flexor hallucis longus to the tendon of the 

 flexor longus digitorum, varies greatly in magnitude and in the manner in 

 which it is connected with the flexor tendons of the toes. In the majority 

 of cases it goes to the tendons of the second and third toes ; in some cases, 

 however, only to the tendon of the second toe, or to the tendons of the 

 second, third, and fourth toes. Very rarely does it divide so as to bring 



