572 APPLIED ANATOMY. 



The flexor longus digitorum and flexor longus hallucis lie too deeply behind 

 the internal malleolus to be recognized; the latter is the more posterior. 



The tibialis posterior, on strongly abducting the foot, can often be seen and felt 

 along the posterior border of the internal malleolus and between the latter and the 

 tubercle of the scaphoid, into which it inserts. 



The tibialis anterior is the tendon nearest the anterior edge of the internal 

 malleolus. It runs down to the internal cuneiform bone about 2.5 cm. (i in.) in 

 front of the tubercle of the scaphoid. 



The extensor longiis hallucis lies just to the outside of the tibialis anterior and 

 can often be made prominent by flexing the big toe. 



The extensor longus digitorum tendons at the ankle lie close together just out- 

 side of the extensor longus hallucis. The peroneiis tertius runs from them to the 

 dorsum of the fifth metatarsal bone a little in front of its base. 



The peroncal tendons can usually be made visible by sharply adducting the foot. 

 The brevis is then seen running back to the peroneal spine 2.5 cm. (i in.) below and 

 a little in front of the external malleolus and from this point up to behind the malle- 

 olus; in thin people both the brevis and longus can be seen and followed up the 

 lower part of the fibula. 



The soft rounded prominence about 5 cm. (2 in.) in front of the external malleo- 

 lus is the extensor brevis digitorum muscle. 



The Joints. The ankle-joint lies 1.25 cm. (^ in.) above the tip of the inter- 

 nal malleolus. 



The midtarsal (Chopart's) joint is best found on the inner side of the foot; here it 

 passes immediately behind the tubercle of the scaphoid. On the outer side it is ap- 

 proximately at the middle of a line joining the external malleolus and tuberosity of 

 the fifth metatarsal bone. At this point there is frequently a bony prominence 

 formed by the anterior edge of the os calcis. 



The tarsometatarsal (Lisfranc's) joint is best found on the outer side of the 

 foot. It lies immediately behind the tuberosity of the fifth metatarsal bone, between 

 it and the cuboid. 



Its inner extremity can be found either by 'following up the first metatarsal bone 

 from its head for about 5 cm. (2 in.) when a ridge of bone will be felt on its base, the 

 joint being immediately behind it; or by identifying the tubercle of the scaphoid and 

 allowing 2.5 cm. (i in.) from its anterior edge for the internal cuneiform bone. Its 

 exact location is to be recognized by pressing with the edge of the thumb at the sus- 

 pected spot and moving the metatarsal bone with the opposite hand. 



THE ARTERIES OF THE FOOT. 



The dorsalis pedis artery runs from the middle of the front of the ankle 

 to the base of the first metatarsal interspace. The extensor longus hallucis tendon 

 is on the medial side and the extensor longus digitorum on the lateral. An in- 

 cision made midway between these tendons exposes the muscular fibres of the ex- 

 tensor brevis digitorum; this is pulled to the outer side and the artery will be found 

 lying on the bone beneath. The extensor brevis digitorum crosses it near its termi- 

 nation. 



This artery is rarely the subject of ligation, but one frequently endeavors to feel 

 its pulsation in order to determine whether the artery above is intact. 



The Plantar Arteries. The tibialis posterior divides into the internal and 

 external plantar arteries at a point midway on a line joining the internal malleolus 

 and internal tubercle of the os calcis. From this point the internal plantar artery 

 runs forward along the medial side of the flexor longus hallucis in the groove between 

 the abductor hallucis and flexor brevis digitorum. It is much the smaller of the two 

 plantar arteries (Fig. 591). 



The external plantar artery runs from the same point as the internal to the 

 inner side of the base of the fifth metatarsal bone. To this point it lies beneath the 

 flexor brevis digitorum and above the accessorius. It then dips deeper, lying on the 

 interossei, and curves inward to end in the communicating artery which pierces 

 the base of the first metatarsal space to anastomose with the dorsalis pedis. 



