240 ANATOMY OP THE LOWER EXTREMITY. 



off numerous muscular twigs, and at the ankle-joint ai 

 external and internal malleolar branch ; these supply th< 

 parts about the joint, anastomosing with the calcanes 

 branches of the posterior tibial and peroneal arteries. 



The anterior peroneal artery, coming from the back 

 the leg, passes through an aperture in the lower part of the 

 interosseous membrane, and is distributed in front of the 

 fibula to the dorsum and outer part of the foot, anastomos- 

 ing with the malleolar branches of the anterior tibial. 



The anterior tibial nerve, one of the divisions of the 

 peroneal nerve, having passed through the opening in the* 

 upper part of the interosseous membrane, will be found 

 emerging from under the belly of the extensor longus mus- 

 cle, to accompany the anterior tibial artery which lies upon 

 its outer side ; on the dorsum of the foot it is distributed 

 as has been described. 



The musculo-cutaneous nerve, the other division of the 

 peroneal nerve, after curving round the head of the fibula 

 and passing beneath the fascia of the leg, lies between the 

 extensor longus and the peronei muscles ; it then pierces 

 the fascia, becomes subcutaneous, and is distributed as has 

 been described. 



The dorsalis pedis artery lies upon the outer side of the 

 tendon of the extensor proprius pollicis; it is accompanied 

 by the anterior tibial nerve ; it distributes some branches 

 to the tarsus, called tarsal, and then forms an arch over 

 the bases of the metatarsal bones ; this arch gives off three 

 interosseous branches which, at the commissures of the 

 third, fourth, and fifth toes, divide into digital branches, 

 to supply the sides of the toes. At each end of the inter- 

 osseous spaces these arteries are joined by perforating 

 branches from the sole of the foot. At the base of the first 

 interosseous space, the dorsalis pedis penetrates to the sole 

 of the' foot, to unite, under the name of the communicating 

 artery, with the termination of the plantar arch ; before 

 disappearing it gives off the dorsalis hallucis branch, which 

 passes forward and is distributed to the great toe and the 

 inner side of the next toe. 



The DORSAL INTEROSSEOUS MUSCLES arise by two heads 

 from the sides of the bases of adjoining metatarsal bones ; 

 they are inserted into the bases of the first phalanges of 

 the toes, and into the expansion of the extensor tendons ; 

 the first interosseous muscle being inserted into the inside 

 of the second toe, and the three others into the outsides of 

 the second, third, and fourth toes. 



