THE MUSCLES IN THE SOLE OF THE FOOT. 



433 



inserted, along with part of the flexor hallucis brevis into the medial side of the 

 base of the first phalanx of the great toe. 



Nerve-Supply. Medial plantar nerve (L. 4. 5. S. 1.). 

 Actions. A flexor and abductor of the great toe. 



M. Flexor Digitorum Brevis. The flexor digitorum brevis has likewise a 

 double origin : (1) from the an- 

 terior part of the medial process 

 of the tuberosity of the calcaneus 

 (Fig. 386, p. 432), and (2) from 

 the thick central part of the 

 plantar aponeurosis which covers 

 it, and from the inter muscular 

 septa on either side. 



It passes forwards, and gives 

 rise to four slender tendons, which 

 are inserted into the second 

 phalanges of the four lateral 

 toes, after having been perforated 

 by the long flexor tendons, just 

 as in the case of the tendons of 

 the flexor digitorum sublirais of 

 the hand (p. 389). 



Nerve - Supply. Medial plantar 

 nerve (L. 4. 5. S. 1.). 



Actions. The muscle is a flexor 

 of the toes, acting on the metatarso- 

 phalangeal and first inter-phalangeal 

 articulations of the four lateral toes. 



Plantar 

 aponeurosis 



ABDUCTOR DIGITI 



QUINTI 



QUADRATUS 

 PLANTS 



FLEXOR . 

 DIGITORUM BREVIS 



ABDUCTOR 

 HALLUCIS 



FLEXOR DIGITI 

 QUINTI BREVIS 



FLEXOR HALLUCIS 



BREVIS 



FOURTH 



LUMBRIOAL 



THIRD 

 LUMBRICAL 

 SECOND... 



LUMBRICAL 



FIRST 

 LUMBRICAL 



FLEXOR 



M. Abductor Digiti Quinti. 

 The abductor digit! quinti 



also has a double origin: (1) by 

 fleshy and tendinous fibres from 

 the anterior part of both pro- 

 cesses of the tuberosity of the 

 calcaneus, partly concealed by the 

 flexor digitorum brevis (Fig. 386, 

 p. 432), and (2) by fleshy fibres 

 from the lateral portion of the 

 plantar aponeurosis and the cal- 

 caneo-metatarsal ligament, and * 

 from the intermuscular septum 

 between it and the flexor digi- 

 torum brevis. 



Its tendon lies along the fifth 

 metatarsal bone, and is inserted 

 into the lateral side of the pos- 

 terior end of the first phalanx of 

 the little toe. The most lateral 

 fibres usually obtain an ad- 

 ditional insertion into the lateral 

 side of the plantar surface of the 

 fifth metatarsal bone. 



Nerve-Supply. Lateral plantar nerve (S. 1. 2.). 

 Actions. Flexion and abduction of the little toe. 



FIG. 387. SUPERFICIAL MUSCLES OF THE RIGHT FOOT. 



SECOND LAYER. 



The tendons of the long flexors of the toes, the lumbricales and quadratus 

 plant* muscles, constituting the second layer of muscles, have already been described 



29 



