THE MUSCLES IN THE SOLE OF THE FOOT. 



435 



M, Flexor Digiti Quinti Brevis. The flexor digiti quinti brevis arises from 

 (1) the sheath of the peronseus longus and (2) the base of the fifth metatarsal 

 bone (Fig. 386, p. 432). 



Partially concealed by the abductor digiti quinti, the muscle passes along the 

 fifth metatarsal bone, to be inserted, in common with that muscle, into the lateral 

 dde of the base of the first phalanx of the little toe. 



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

 Actions. Flexion of the little toe. 



FOURTH LAYER. 



Mm. Interossei, The interossei muscles of the foot resemble those of the 

 and except in one respect. In the hand the line of action of the muscles is the 

 iddle line of the 

 iddle finger. In 

 e foot the second 

 is the digit 

 >und which the 

 uscles are 

 >uped, and their 

 ittachrnents and 

 heir actions 

 liffer accordingly. 

 There are four 

 >rsal and three 

 intar muscles, 

 rhich occupy to- 

 ither the four in- 

 jeous spaces, 

 id project into 

 hollow of the 



The four 

 >rsal muscles, 



in each interosseous space, arise by two heads each from the shafts of adjacent 

 letatarsal bones. 



Each gives rise to a tendon, which, after passing dorsal to the transverse 

 letatarsal ligament, is inserted on the dorsum of the foot, into the side of the first 

 )halanx, the metatarso-phalangeal capsule, and the dorsal expansion of the 

 :tensor tendon. The first and second muscles are inserted respectively into the 

 tedial and lateral sides of the proximal end of the first phalanx of the second toe. 

 third and fourth muscles are inserted into the lateral sides of the third and 

 mrth toes. 



The three plantar muscles occupy the three lateral interosseous spaces. Each 

 rises, by a single head, from the medial side of the third, fourth, and fifth metatarsal 

 >nes respectively. 



Each ends in a tendon which passes dorsal to the transverse metatarsal ligament, 

 id is inserted, in the same manner as the dorsal muscles, into the medial sides of 

 the third, fourth, and fifth toes. 



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



Actions. The muscles are flexors of the metatarso-phalangeal joints, and extensors of the 

 inter-pbalangeal joints of the four lateral toes. The dorsal interossei abduct the toes into which 

 "ley are inserted from the middle line of the second toe. The plantar interossei adduct the 

 iree lateral toes towards the second toe. 



Actions of the Muscles of the Leg and Foot. 



The muscles of the leg and foot act chiefly in the movements of the ankle-joint (assisted by 



FIG. 389. INTEROSSEOUS MUSCLES OF THE RIGHT FOOT. 



proximal 



of 



