THE LEG. 



FIG. 8 7 .-The plantar aspect of the foot. The flexor brevis digitorum muscle has been divided and portions have been 

 cut out of the flexor longus digitorum, adductor hallucis, and flexor brevis hallucis muscles! 



behind the sustentaculum tali of the os calcis to the sole of the foot, crosses the tendon of the 

 flexor longus digitorum, and is attached to the second phalanx of the great toe. Between the 

 internal malleolus and the tuber calcanei each of the tendons of the flexor longus digitorum, 

 tibialis posticus, and flexor longus hallucis possesses an individual synovial sheath which is 

 bridged over by the internal annular ligament (ligamentum laciniatum). 



Anterior Tibial Artery. After the popliteal artery divides into its two terminal branches 

 at the upper margin of the soleus muscle, the anterior tibial artery (Fig. 85) gives off a small 

 posterior recurrent branch and passes anteriorly above the upper margin of the interosseous 

 membrane. The vessel runs downward upon the anterior surface of the interosseous mem- 

 brane, being situated at first between the tibialis anticus and extensor longus digitorum muscles, 

 and then between the former and the extensor longus hallucis. Above the malleolar region the 

 artery lies directly upon the external surface of the tibia; it then passes beneath the anterior an- 

 nular ligament and runs forward upon the foot as the dorsalis pedis. During life the course of 

 the artery is indicated by a line drawn from a point midway between the tubercle of the tibia and 

 the head of the fibula to a point upon the anterior surface of the ankle midway between the two 

 malleoli. In addition to muscular branches, the vessel gives off the anterior tibial artery above, 

 which runs upward to the anastomosis about the knee, and the external and the internal malle- 

 olar arteries below. None of the branches are of great importance from a practical standpoint. 

 The artery is accompanied by the anterior tibial nerve (Fig. 85). This nerve pierces the origin 

 of the extensor longus digitorum and runs at first to the outer side of the artery and then on top 

 of it to the dorsum of the foot. It is the motor nerve for the three extensor muscles and for 

 the extensor brevis digitorum upon the dorsum of the foot. The musculocutaneous nerve is 

 more superficial than the preceding; it passes between the peroneus longus and brevis muscles, 

 supplying both, pierces the deep fascia at the junction of the inferior and middle thirds of the 

 leg, and divides, before reaching the foot, into an external and an internal branch (N. cutaneus 

 dor si pedis medial is and intermedius) . In paralysis of the peroneal nerve the patient stumbles 

 over his own toes and loses sensation over almost all of the dorsum of the foot. 



Posterior Tibial Artery. The posterior tibial artery (Fig. 86) runs between the soleus 

 and tibialis posticus, beneath the flexor longus hallucis, and then between the flexor longus 

 digitorum and the flexor longus hallucis. It is superficial and easily accessible between the 

 tendo Achillis and the internal malleolus. In this situation it is placed to the inner side of the 

 posterior tibial nerve and may be readily ligated. In tenotomy of the tendo Achillis the artery 

 can scarcely be injured if ordinary care is observed. Behind the internal malleolus the vessel 

 divides into its terminal branches the external and internal plantar arteries. In the ligation of 

 the artery behind the internal malleolus particular care must be taken to avoid opening the 

 synovial sheath of the tibialis posticus, which lies immediately to the inner side of the vessel 

 (Fig. 87). The chief branch of the posterior tibial, the peroneal artery (Fig. 86), arises high up, 

 runs downward behind the fibula covered by the flexor longus hallucis muscle, and ends at the 

 outer side of the os calcis with branches to the rete calcanei. The posterior tibial nerve, the 



