492 Anterior Tibial Artery 



The tibialis anti jus .irises from the outer aspect of the tibia, the 

 deep fascia, and the interosseous membrane. It is inserted into the 

 internal cuneiform and the scaphoid bones. Its tendon has a syno- 

 vial sheath as it descends beneath the two bands of the annular liga- 

 ment. Its action is to flex and invert the foot ; its tendon often has 

 to be divided in talipes varus. The tenotomy is best performed just 

 below the front of the inner malleolus. 



The extensor longus digltorurn arises from the outer tuberosity 

 of the tibia, the anterior surface of the fibula, and the deep fascia. Its 

 tendons are inserted into the second and third phalanges of the four 

 outer toes. The anterior tibial nerve comes through the upper end 

 of its origin. The peroneus terrius is continued from the lowest 

 part of this muscle, and is inserted into the dorsal surface of the base 

 of the fifth metatarsal bone. 



The extensor prop.ius hallucfs (pollicis] arises from the middle 

 two-fifths of the front of the fibula, and from the interosseous mem- 

 brane ; it is inserted into the ungual phalanx of the great toe. 



Course. At first it lies on the outer side of the anterior tibial 

 artery, and to the inner side of the extensor longus digitorum between 

 that muscle and the tibialis anticus, and overlapped by them. It 

 then slowly crosses over the artery, and at the ankle its tendon lies to 

 the inner side of the artery. 



The foregoing muscles are flexors of the foot ; they are supplied 

 by the anterior tibial nerve. 



The peroneus longus and brevis arise down the outer side of the 

 fibula, the brevis being to the front of the longus and overlapped by 

 it. They lie between the extensor longus digitorum and the peroneus 

 tertius, to the front, and the soleus and flexor longus hallucis behind. 

 Their tendons groove the back of the external malleolus and the 

 outer side of the os calcis, the shorter tendon being above the peroneal 

 tubercle, and the longer below it. The shorter tendon is then inserted 

 into the outer side of the base of the fifth metatarsal bone, whilst the 

 longer runs forwards and inwards in the tunnel under the cuboid bone, 

 to be inserted into the tuberosity of the internal cuneiform and the 

 outer side of the base of the first metatarsal bone. 



These two muscles, which are supplied by the musculo-cutaneous 

 nerve, extend and evert the foot, and in the case of extreme talipes 

 valgus their tendons require division behind the malleolus. The 

 external popliteal nerve divides in the substance of the longer muscle 

 just below the head of the fibula. The tendons have a common 

 synovial investment as they groove the malleolus. 



The anterior tibial artery is one of the divisions of the popliteal. 

 It comes through the top of the interosseous membrane, and runs 

 clown thereon until it rests upon the front of the expanded, lower 

 end of the tibia. It afterwards lies upon the anterior ligament of the 

 ankle-joint, where it changes its name to dorsalis pedis. 





