202 



DISSECTION OF THE FOOT. 



Dissect the 

 next 



muscular 

 layer, 



and plantar 

 vessels and 



Two plantar 

 arteries : 



inner and 

 outer. 



Internal 

 small ; 



course and 

 ending. 



Branches to 

 muscles ; 



and super- 

 ficial digital; 



first, 

 second, 

 third, 

 fourth. 



External 

 artery has 

 a curved 

 course ; 



partly 

 superficial, 

 partly deep. 



ttuperficial 

 part : 



relations ; 



Dissection (fig. 77). To bring into view the second layer of 

 muscles and the plantar vessels and nerves, the muscles already 

 examined must be reflected. Cut through the flexor brevis digi- 

 torum at the os calcis, and as it is raised, notice a branch of 

 nerve and artery to it. Divide the abductor minimi digiti near 

 its origin, and in turning it to the outer side of the foot, seek its 

 nerve and vessel close to the calcaneum. The abductor hallucis 

 can be drawn aside if it is necessary, but at present it may remain 

 uncut. 



Next, the internal plantar vessels and nerve are to be followed 

 forwards to their termination, and backwards to their origin ; and 

 the external plantar vessels and nerve, the tendons of the long 

 flexors of the toes, the accessory muscle, and the small lumbricales, 

 should be freed from fat. 



The PLANTAR ARTERIES (fig. 77) are the terminal branches of 

 the posterior tibial trunk, and supply digital offsets to the toes. 

 They are two in number, and are named external and internal 

 from their relative position in. the sole of the foot : the external is 

 the larger, and forms the plantar arch. 



The INTERNAL PLANTAR ARTERY (a) is inconsiderable in size, 

 and accompanies the internal plantar nerve, under cover of the 

 abductor hallucis, as far as the middle of the foot, where it ends 

 in four superficial digital branches. 



Branches. The artery furnishes muscular branches, ' like the 

 nerve, to the abductor hallucis, flexor brevis digitorum, and the 

 flexor brevis hallucis. Its digital branches accompany the digital 

 nerves of the internal plantar (fig. 75), and are thus disposed : 



The first is distributed to the inner side of the foot and great 

 toe ; the second is directed to the first interdigital space ; the third 

 to the second space ; and the fourth to the third space. At the 

 root of the toes the last three join the deeper digital arteries in 

 those spaces. 



The EXTERNAL PLANTAR ARTERY (6) takes an arched course in 

 the foot, with the concavity of the arch turned inwards. The vessel 

 first passes outwards across the sole towards the base of the fifth 

 metatarsal bone, and then turns obliquely inwards towards the root 

 of the great toe, so that it crosses the foot twice. In the first half 

 of its extent, viz., as far as the base of the metatarsal bone of the 

 little toe, the artery is comparatively superficial ; in the other 

 half, between the little and the great toe, it lies deeply in the 

 foot, and forms the plantar arch. 



Only the first part of the artery is now laid bare ; the remaining 

 portion, supplying the digital branches, will be noticed after the 

 examination of the third layer of muscles (p. 207). 



As far as the metatarsal bone of the little toe, the vessel is con- 

 cealed by the abductor hallucis and the flexor brevis digitorum ; 

 but for a short distance near its termination it lies in the interval 

 between the last muscle and the abductor minimi digiti. It rests 

 on the os calcis and flexor accessorius ; and it is accompanied by 

 vense comites and the external plantar nerve. 



