THE DORSAL IS PEDIS ARTERY. 643 



which lie on each side of the vessel, some piercing the deep fascia to supply the 

 integument, others passing through the interosseous membrane, and anastomosing 

 with branches of the posterior tibial and peroneal arteries. 



The malleolar arteries supply the ankle-joint. The internal arises about two 

 inches above the articulation, and passes beneath the tendons of the Extensor 

 proprius hallucis and Tibialis anticus to the inner ankle, upon which it ramifies, 

 anastomosing with branches of the posterior tibial and internal plantar arteries 

 and with the internal calcanean from the posterior tibial. The external passes 

 beneath the tendons of the Extensor longus digitorum and Peroneus tertius, and 

 supplies the outer ankle, anastomosing with the anterior peroneal artery and with 

 ascending branches from the tarsal branch of the dorsalis pedis. 



The Dorsalis Pedis Artery (Fig. 378). 



The dorsalis pedis, the continuation of the anterior tibial, passes forward from 

 the bend of the ankle along the tibial side of the foot to the back part of the first 

 intermetatarsal space, where it divides into two branches, the dorsalis hallucis, and 

 communicating, or first dorsal interosseous artery and. plantar digital respectively. 



Relations. This vessel, in its course forward, rests upon the astragalus, navic- 

 ular. and internal cuneiform bones and the ligaments connecting them, being cov- 

 ered by the integument and fascia, anterior annular ligament, and crossed near 

 its termination by the innermost tendon of the Extensor brevis digitorum. On 

 its tibial side is the tendon of the Extensor proprius hallucis ; on its fibular side, 

 the innermost tendon of the Extensor longus digitorum, and the termination of the 

 anterior tibial nerve. It is accompanied by two veins. 



PLAX OF THE RELATIONS OF THE DORSALIS PEDIS ARTERY. 



In front. 



Integument and fascia. 



Anterior annular ligament. 



Innermost tendon of Extensor brevis digitorum. 



Tibial side. I _ lia \ Fibular side. 



Extensor proprius hallucis. * j Extensor long digitorum. 



Anterior tibial nerve. 



Behind. 



Astragalus. 

 Navicular. 

 Internal cuneiform, 

 and their ligaments. 



Peculiarities in Size. The dorsal artery of the foot may be larger than usual, to compen- 

 sate for a deficient plantar artery; or it may be deficient in its terminal branches to the toes, 

 which are then derived from the internal plantar ; or its place may be supplied altogether by a 

 large anterior peroneal artery. 



Position. This artery frequently curves outward, lying external to the line between the 

 middle of the ankle and the back part of the first interosseous space. 



Surface Marking. The dorsalis pedis artery is indicated on the surface of the dorsum of 

 the foot by a line drawn from the centre of the space between the two malleoli to the back of the 

 first internietatarsal space. 



Surgical Anatomy. This artery may be tied, by making an incision through the integu- 

 ment between two and three inches in length, on the fibular side of the tendon of the Extensor 

 proprius hallucis. in the interval between it and the inner border of the short Extensor muscle. 

 The incision should not extend farther forward than the back part of the first intermetatarsal 

 space, as the artery divides in that situation. The deep fascia being divided to the same extent, 

 the artery will be exposed, the nerve lying upon its outer side. 



