INTEBOSSEI MUSCLES. 



291 



the external head of the flexor accessorius, the ligamentum longum plantse, the 

 peroneus longus, and the flexor brevis minimi digiti. 



The flexor brevis minimi digiti arises by tendinous fibres from the base of 

 the fifth metatarsal bone, and from the sheath of the peroneus longus, and 

 terminates in a tendon which is inserted into the base and external border 

 of the first phalanx of the little toe. It is covered partly by the abductor 

 minimi digiti, partly by the plantar fascia. 



THE INTEROSSEOUS MUSCLES of the foot, like those of the hand, are seven 

 in number, three plantar and four dorsal ; the plantar iuterossei, visible 

 only from the under side, arise each from only one metatarsal bone, and 

 their action is to approximate the toes ; the dorsal muscles, visible both from 

 above and below, arise each from two metatarsal bones, and in their action 

 separate the toes. The arrangement of the second dorsal and first plantar 

 interosseous muscles of the foot, in relation to the toes, is somewhat different 

 from that of the corresponding muscles of the hand. 



Fig. 222, A. DEEP DISSECTION OP THE Fig. 222. 



DORSUM OF THE FOOT, TO SHOW THE A g 



DORSAL INTEROSSEOUS MUSCLES. \ 



1, 2, 3, 4, the several dorsal inter- 

 osseous muscles : the final insertion of 

 the extensor tendons into the phalanges of 

 the toes is also shown in this figure, more 

 particularly in the great toe, and the sepa- 

 rate insertion of the tendons of the short 

 and the long extensor. 



B. DEEP DISSECTION OF THE SOLE OF 

 I'HE FOOT, TO SHOW THB PLANTAR 

 INTEROSSEOUS MUSCLES. . 



1, 2, 3, the three plantar interossu ; 

 this figure also shows the long and short 

 plantar ligaments, and the insertion of the 

 tendon of the peroneus longus muscle into 

 the first metatarsal Lone. 



The dorsal interossei are arranged 

 so as to separate the toes from the 

 line in which the second toe rests ; 

 they lie one in each interspace, their 

 fibres radiating pennately from a 

 central tendon ; and they terminate 

 partly in the first phalanx and partly 



in the extensor aponeurosis of the toe to which each belongs. The first 

 two are inserted one on each side of the second toe ; the third and fourth 

 are inserted on the outer sides of the third and fourth toes. 



The plantar interossei, arranged so as to approximate the three outer toes 

 to the second, arise from the inner and under surfaces of the third, fourth, 

 and fifth metatarsal bones, and are inserted in a manner similar to the dorsal 

 interossei into the inner sides of the first phalanges of the third, fourth, 

 and fifth toes. 



ACTIONS OF THE MUSCLES OF THE LEG AND FOOT. There is only one muscle of the 

 leg, viz., the popliteus, which acts on the knee-joint alone. Its principal action is 

 that of a rotator inwards of the lower leg ; and it is interesting to observe that while 

 rotation of the leg at the knee-joint occurs only in flexion, it is in that position only 

 that the tendon of the popliteus lies in its groove on the femur. 



