244 ANATOMY OF THE LOWER EXTREMITY. 



sheath of the internal annular ligament, below the tubercl< 

 of the os calcis, and, entering the sole of the foot, is insertc 

 into the last phalanx of the great toe. The posterior tibh 

 nerve lies along the inner side of this muscle, and the pen 

 neal vessels are in part concealed by it. 



The TIBIALTS POSTICUS MUSCLE occupies a position be- 

 tween the two bones of the leg, and between the two mus- 

 cles last described. It arises from nearly the whole length 

 of both tibia and fibula, and from the interosseous mem- 

 brane ; its origin superiorly forms, as it were, two heads, 

 between which passes the anterior tibial artery; its tendon 

 curves around the internal malleolus, passing through the 

 sheath in the internal annular ligament which is nearest 

 the malleolus, and enters the sole of the foot, to be inserted 

 into the scaphoid and external cuneiform bones, and into 

 the base of the first metatarsal bone. 



Along the outer border of the leg, and upon the fibula, 

 will be found two muscles, the peroneus longus and pero- 

 neus brevis. 



The PERONEUS LONGUS MUSCLE arises from the head and 

 upper part of the surface of the fibula, and terminating in 

 a long tendon, curves around the external malleolus, and 

 passes through the sheath of the external annular liga- 

 ment; entering the sole of the foot, it crosses obliquely 

 forward to be inserted into the base of the metatarsal bone 

 of the great toe. The musculo-cutaneous nerve lies be- 

 tween this muscle and the extensor-longus digitornm. 



The PERONEUS BREVIS lies beneath the preceding muscle, 

 and arises from the lower half of the outer surface of the 

 fibula; its fibres are inserted in a penniform manner into a 

 tendon which passes beneath the external annular ligament, 

 with the peroneus longus, and is inserted into the base of 

 the metatarsal bone of the fifth toe. 



The INTERNAL ANNULAR LIGAMENT confines the tendons 

 which curve around the inner ankle from the back of the 

 leg ; it stretches across from the tip of the internal mal- 

 leolus to the side of the os calcis, and contains three com- 

 partments, lined by synovial membrane, which transmit 

 the tendons of the tibialis posticus, flexor longus digitorum 

 pedis, and flexor longus pollicis, in the order in which they 

 have been mentioned, that of the tibialis posticus being 

 nearest the malleolus. 



The EXTERNAL ANNULAR LIGAMENT stretches across 

 from the tip of the external malleolus to the side of the os 



