THE POSTERIOR TIBIAL ARTERY. 



841 



ThQjifth plantar interosseous artery is considerably larger than the others, and arises from 

 the inner end of the plantar arch, opposite the communicating branch which passes between the 

 plantar arch and the dorsalis pedis. It runs forward at first along the first intermetatarsal space 

 and then upon the first metatarsal bone, and gives off a digital branch which passes to the inner 

 surface of the great toe and continues on towards the metatarso-phalangeal joint of that digit. 

 Before reaching this, however, it gives off an anterior perforating branch and then divides uito 

 two plantar digital branches, which supply respectively the inner side of the second and the 

 outer side of the great toe. 



Since the communicating branch which traverses the first intermetatarsal space is some- 

 times regarded as the terminal portion of the dorsalis pedis artery, and tlie fifth plantar inter- 

 osseous artery seems to be, upon such a view, the branch of the communicating vessel, the fifth 

 plantar has been de- 

 scribed as a branch of Fig, 740. 

 the dorsalis pedis ar- 

 tery, under the name of 

 the a. princeps hallucis. 

 There can be no doubt, 

 however, that both the 

 communicating and 

 the princeps are equiv- 

 alent to the other pos- 

 terior perforating and 

 plantar interosseous 

 arteries. 



Tendo Achillis 



Posterior tibia 



Internal malleolar 



Internal lateral 



ligament 



Internal plantar 



Flexor longus 



hallucis tendon 



Adductor 



obliquus, cut 



Princeps hallucis 

 (V. interosseous) 

 dividing into 

 digital branches 



Internal calcanean 



— Abductor hallucis 



Internal calcanean of ext. 

 External [plantar 



plantar 



Flexor brevis digitoruni 



Flexor accessorius 

 Superficial fascia 



Abductor minimi digiti 



II. and III. plantar 

 interossei and flexor 

 brevis minimi digiti 



I.-IV. interosseous 

 arteries dividing into 

 digital branches 



Variations. — The 

 external plantar artery 

 may be quite small, in 

 which case the plantar 

 arch seems to be a 

 continuation from the 

 anterior tibial artery 

 through the posterior 

 perforating branch of 

 the first intermetatar- 

 sal space. The arch 

 is occasionally double, 

 owrng to its division 

 at its origin into two 

 stems which reunite 

 opposite the first inter- 

 metatarsal space. The 

 first plantar interosse- 

 ous may arise by a 

 common stem with the 

 second, and, con- 

 versely, one or more 

 of the plantar digital 

 branches may have an 

 independent origin 

 from the arch. 



Anastomoses 

 of the Posterior 

 Tibial Artery. — A 



collateral circulation 



for the posterior tibial after interruption of that vessel below the origin of the 

 peroneal may readily be established through the anastomoses which its branches 

 form with those of the peroneal and those of the anterior tibial. The anasto- 

 moses with the peroneal are between the communicating branches of the two 

 arteries, between the anterior peroneal and the external plantar, and between the 

 posterior peroneal and the internal calcaneal. With the anterior tibial artery there 

 is communication through the malleolar branches of the two arteries, through the 

 anastomotic branch of the external plantar and the tarsal and metatarsal branches 

 of the dorsalis pedis, and through the union of anterior and posterior perfo rating- 

 branches of the plantar arch and the plantar interosseous arteries with the dorsalis 

 pedis and dorsal interosseae. 



Arteries of plantar surface of right foot ; deeper dissection. 



