THE ANTEKIOK TIBIAL AETEEY. 955 



plantar artery gives off (a) the medial calcanean branch, which is distributed to the skin 

 and the subcutaneous tissue of the heel. 



(6) Muscular branches to the abductor hallucis, flexor digitorum brevis, quadratus 

 plantse, and abductor digiti quinti. 



(c) Cutaneous branches to the skin of the lateral side of the foot. 



Between the base of the fifth metatarsal bone and the first interosseous space it forms 

 the plantar arch, and gives off (d) four plantar metatarsal branches ; (e) three 

 posterior perforating arteries to the dorsal metatarsal arteries ; and (/) articular branches 

 to the tarsal joints. 



The fifth or most lateral metatarsal branch runs along the lateral side of the little 

 toe, supplying the skin, joints, and the flexor tendons with their synovial sheaths. The 

 three medial plantar metatarsal branches, second, third, and fourth, run forwards on the 

 plantar surfaces of the interossei, the medial two lying dorsal to the oblique head of 

 the adductor of the great toe, and all three passing dorsal to the transverse head of the 

 adductor. At the bases of the interdigital clefts the second, third, and fourth plantar 

 metatarsal arteries divide into plantar digital arteries which run along the plantar aspects 

 of adjacent toes, and supply skin, joints, and the flexor tendons and sheaths. Opposite 

 the last phalanx of each toe the digital arteries of opposite sides of the toe anastomose 

 together. 



The posterior perforating arteries are three in number ; they pass dorsal wards through 

 the three lateral intermetatarsal spaces, between the heads of the dorsal interosseous 

 muscles, and terminate by uniting with the corresponding dorsal metatarsal arteries. 

 Anterior perforating branches which communicate with the dorsal metatarsal arteries are 

 given off from two or three of the plantar metatarsal arteries just before they divide. 



The articular branches are numerous and irregular ; they supply the joints and 

 ligaments of the tarsus on its plantar aspect. 



ARTERIA TIBIALIS ANTERIOR. 



The anterior tibial artery, the smaller of the two terminal divisions of 

 the popliteal, commences opposite the distal border of the popliteus muscle, and 

 terminates in front of the ankle, where it is continued into the dorsal artery of 

 the foot. 



Course and Relations. From its origin, at the back of the leg, the artery 

 passes anteriorly, between the two slips of the proximal part of the tibialis 

 posterior and above the proximal border of the interosseous membrane. It then 

 runs distally, resting, in the proximal two-thirds of its course, against the anterior 

 surface of the interosseous membrane and, subsequently, on the distal part of the 

 tibia and the anterior ligament of the ankle-joint. In the proximal third of the 

 anterior compartment of the leg it lies between the extensor digitorum longus 

 laterally and the tibialis anterior medially; in the middle third it is between 

 the extensor hallucis longus and the tibialis anterior; in the distal third the 

 extensor hallucis longus crosses in front of the artery and reaches its medial 

 side, and the most distal part of the vessel lies between the tendon of the extensor 

 hallucis longus on the medial side and the most medial tendon of the extensor 

 digitorum longus on the lateral side. 



The deep peronaeal nerve (O.T. anterior tibial) is at first well to the lateral side 

 of the artery, but it soon passes in front of the vessel, and it lies in front of the 

 middle third of the artery ; more distally the nerve is usually found on the 

 lateral side again, and at the ankle it intervenes between the artery and the most 

 medial tendon of the extensor digitorum longus. 



Two vense comites, with numerous intercommunications, accompany the artery. 



Obviously the anterior tibial artery is, at least in its proximal part, deeply placed; 

 moreover, its lateral muscular boundaries overlap it. In the distal two-thirds of 

 its extent it is, however, easily accessible from the surface ; and beyond being 

 covered by the nerve and crossed by the tendon, as already described, is only 

 covered, in addition, by skin, fascia, and the transverse crural ligament. 



Branches. Close to its origin the artery gives off fibular and posterior tibial 

 recurrent branches; after it reaches' the front of the leg it gives off anterior tibial 

 recurrent, muscular, cutaneous, medial malleolar, and lateral malleolar branches: 



