600 THE ARTERIES 



THE DORSALIS PEDIS ARTERY 



The dorsalis pedis artery is a continuation of the anterior tihiah It extends 

 from the front of the ankh^-joint to the })roximal end of the first interosseous 

 space where it dips into the sole to join the external ]jlantar artery and comj^lete 

 the plantar arch. The course of the artery is indicated hy a line drawn from a 

 point midway between the two malleoli to the proximal end of tlie first metatarsal 

 space. 



Relations.— Behind, the artery from above downwards lies successively on 

 the astragalus, scaphoid, middle cuneiform, and the base of the second metatarsal 

 l)ones, and the ligaments uniting these bones. As it sinks into the sole, under the 

 name of the connnunicating artery, it lies between the two heads of origin of the 

 first dorsal interosseous muscle. At times it takes a course a little more outwards, 

 then lying either partly on the middle cuneiform bone, or on the dorsal ligaments 

 uniting the middle cuneiform to the internal cuneiform. It is more or less bound 

 down to the l:)ones by aponeurotic fibres derived from the deep fascia. 



In front, the artery is covered by the anterior annular ligament, sometimes by 

 the extensor longus hallucis, by the skin, the superficial and deep fascia, and, just 

 before it sinks into the sole, by the innermost tendon of the extensor brevis digi- 

 torum. The angle formed by this tendon with the extensor longus hallucis is the 

 best guide to finding the artery in. the process of ligature (fig. 380). 



To its outer side is the innermost tendon of the extensor longus digitorum, and 

 lower down the innermost tendon of the extensor brevis digitorum. The anterior 

 til)ial nerve is also to its outer side, as is also the outermost of its vena? comites. 



To its inner side is the extensor longus hallucis, except at times for al)out half 

 an inch below, where the innermost tendon of the extensor brevis digitorum, having 

 crossed the artery, may lie between it and this tendon. The innermost of the vena* 

 comites is also to the inner side. Branches lietween the venae comites at intervals 

 cross the vessel. 



The branches of the dorsalis pedis artery are: — (1) The tarsal; (2) the meta- 

 tarsal; (3) the dorsalis hallucis; and (4) the communicating, or plantar digital. 



(1) The tarsal branches may l)e divided into (a) the external, and {h) the 

 internal, (a) The external tarsal runs outwards over the scaphoid and cu))oid 

 bones, beneath the extensor brevis digitorum. It supplies branches to that muscl(\ 

 and to the bones and the articulations between them, and anastomoses above with 

 the external malleolar and anterior peroneal, below with the metatarsal, and extern- 

 ally over the outer border of the foot with the anastomotic branches of the external 

 plantar artery. (6) The internal tarsal consists of a few small branches which 

 run over the inner side of the foot, supplying the skin and articulations, and anas- 

 tomose with the internal malleolar. 



(2) The metatarsal artery ffigs. 380, 381) runs outwards across the foot, in a 

 slight curve with the convexity forwards, over the bases of the metatarsal bones, 

 and beneath the extensor tendons and the extensor brevis digitorum. At the out(»r 

 border of the foot it anastomoses, above with the external tarsal, and externally 

 with the anastomotic l^ranches of the external ])lantar. From the convexity of the 

 arch it gives off three dorsal interosseous arteries, which run forwards on the 

 dorsal interosseous muscles in the centre of the second, third, and fourth inter- 

 osseous spaces to the cleft of the toes, where they bifurcate for the supply of the con- 

 tiguous sides of the second and third toes, the third and fourth toes, and the fourth 

 and fifth toes. The outermost of the interosseous branches gives off a small vessel 

 for the supply of the outer side of the little toe. At the proximal end of the second, 

 third, and fourth interosseous spaces each artery receives a branch of comnnmica- 

 tion from the external plantar artery (posterior perforating), and immediately 

 before they bifurcate a second commvmicating artery through the distal end of the 

 interosseous space from the corresponding digital vessel (anterior perforating 

 artery). 



The little dorsal digital vessels, into which the dorsal interosseous arteries 

 divide at the cleft of the toes, run along the side of each toe towards the dorsal 

 aspect, anastomosing with each other across the dorsum of the toes and by frequent 



