632 THE BLOOD-VASCULAR SYSTEM 



lateral malleolar. In addition, ten or twelve muscular branches are given off 

 irregularly to the adjacent muscles along the artery. 



(1) The posterior tibial recurrent artery [a. recurrens tibialis posterior] is occasionally absent. 

 It ascends between the popliteus muscle and the popliteal ligament of the knee-joint, supplying 

 these structures and the superior tibio-fibular joint. It anastomoses with the inferior lateral 

 articular branch of the pophteal, and to a less extent with the inferior medial articular branch. 



_ (2) The anterior tibial recurrent [a. recurrens tibialis anterior] is given off from the anterior 

 tibial artery immediately after that vessel has passed above the interosseous membrane. It 

 winds tortuously through the substance of the tibialis anterior muscle, over the lateral condyle 

 (tuberosity) of the tibia close to the bone; and, perforating the deep fascia, ramifies on the lower 

 and lateral part of the capsule of the knee-joint. It anastomoses with the inferior and superior 

 lateral articular branches of the pophteal, with the descending branch of the lateral circumflex, 

 and somewhat less freely with the medial articular branches of the pophteal and with the genu 

 suprema (anastomotica magna) . It gives off small branches to the tibialis anterior, the extensor 

 digitorum longus, the knee-joint, and the contiguous fascia and skin. It forms one of the col- 

 lateral channels by which the blood is carried to the hmb below in obstruction of the pophteal 

 artery (fig. 503). 



(3) The medial malleolar [a. maUeolaris anterior medialis], the smaller of the two malleolar 

 branches, arises from the lower part of the anterior tibial artery a little higher than the lateral, 

 usually about the spot where the tendon of the extensor haUucis longus crosses the anterior 

 tibial artery. It winds over the medial malleolus, passing beneath the tibiaUs anterior, and 

 joins the medial malleolar rete anastomosing with branches from the posterior tibial artery. 



(4) The lateral malleolar artery [a. maUeolaris anterior lateralis], larger than the medial, 

 arises from the lateral side of the anterior tibial artery, usually on a lower level than the medial 

 malleolar. It winds downward and laterally round the lateral malleolus, passing beneath the 

 extensor digitorum longus and peroneus tertius, and joins the lateral malleolar rete by anas- 

 tomosing with the perforating peroneal, the termination of the peroneal, and the lateral tarsal 

 branch of the dorsalis pedis (fig. 503). 



The anastomosis between the lateral malleolar and perforating peroneal is sometimes of 

 considerable size, supplying the blood to the dorsal artery of the foot; the anterior tibial, then 

 much reduced in size, usually ends at the place of origin of the lateral malleolar. 



THE DORSALIS PEDIS ARTERY 



The dorsalis pedis artery [a. dorsalis pedis] (fig. 503) is a continuation of the 

 anterior tibial. It extends from the front of the ankle-joint to the proximal end 

 of the first interosseous space, where it ends, as the deep plantar branch, by joining 

 the lateral plantar artery to complete the plantar arch. It is accompanied by 

 two venae comitantes. The course of the artery is indicated by a line drawn from 

 a point midway between the two malleoli to the proximal end of the first metatar- 

 sal space. 



Relations. — Behind, the artery from above downward lies successively on the talus (astrag- 

 alus), navicular, second cuneiform, and the base of the second metatarsal bones, and the Uga- 

 ments uniting these bones. At times its course is a little more lateral, lying either partly on 

 the second cuneiform bone, or on the dorsal ligaments uniting the second cuneiform to the first 

 cuneiform. It is more or less bound down to the bones by aponeurotic fibres derived from the 

 deep fascia. 



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

 extensor hallucis longus, by the skin, the superficial and deep fascia, and, just before its termi- 

 nation, by the tendon of the extensor hallucis brevis. The angle formed by this tendon with the 

 extensor hallucis longus is the best guide to finding the artery in the process of Hgature (fig. 503) . 



To its lateral side is the most medial tendon of the extensor digitorum longus, and lower 

 down the tendon of the extensor hallucis brevis. The deep peroneal (anterior tibial) nerve is 

 also to its lateral side. 



To its medial side is the extensor hallucis longus, except at times for about half an inch below, 

 where the tendon of the extensor haUucis brevis, having crossed the artery, may lie between it 

 and this tendon. 



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

 ate; and (3j the deep ])hintar. 



(1) The tarsal branches may be divided into (a) the lateral and (b) the medial, (a) The 

 lateral tarsal artery [a. tarsca lateralis] runs laterally over the navicular and cuboid bones beneath 

 the extensor digitorum brevis. It supplies branches to that muscle, and to the bones and the 

 articulations between them, and anastomoses above with the lateral malleolar and perforating 

 (anterior) peroneal, below with the arcuate (metatarsal) and, over the lateral border of the foot, 

 with the anastomotic branches of the lateral plantar artery, (b) The medial tarsal arteries 

 [aa. tarsea; mediales] consists of a few small branches which run over the medial side of the foot, 

 supplying the skin and articulations, and anastomose with the medial malleolar. 



(2) Tlio arcuate (metatarsal) artery [a. arcuata] (figs. 5()3, 504) runs laterally across the 

 foot, in a slight curve with tlic fonvexity forward, over the ba.ses of the metatarsal bones, and 

 beneath the extensor tendons and the exten.sor digitorum brevis. At the lateral border of the 

 foot it anastomoses, with the lateral tarsal, and with branches of the lateral plantar. 



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