THE FOOT AND ANKLE. 1465 



instead of disarticulating at " Lisfranc's joint," to saw through the metatarsal bones 

 just in front of their bases. 



The metatarso-phalangeal articulations are situated 1 in. behind the web of the 

 toes. In disarticulating a toe, the transverse metatarsal ligament, which unites 

 the heads of the metatarsal bones, should not be injured. 



The tendon of the tibialis posterior may be felt, and, by inverting the foot, seen, 

 as it extends from behind the tip of the medial malleolus to the tuberosity of the 

 navicular ; it crosses the talus immediately above the sustentaculum tali. 



In the commonest form of club-foot, viz., talipes equino-varus, the tuberosity of the 

 navicular is approximated to the medial malleolus, so that tenotomy of the tendon 

 should be performed through a puncture a little distal to the tip of the medial malleolus ; 

 if the knife, after dividing the tendon, is carried down to the bone, the plantar calcaneo- 

 navicular ligament will be divided and the talo-navicular joint opened, a procedure 

 which is called for before the foot can be brought into good position. 



Crossing the front of the ankle-joint, from medial to lateral side, are the 

 following tendons, viz. : the tibialis anterior, the largest and most prominent ; the 

 extensor hallucis longus, the extensor digitorum longus, and the peronaeus tertius. The 

 extensor digitorum brevis gives rise to a fleshy pad which overlies the dorsal aspect 

 of the calcaneo-cuboid joint. When the foot is everted, the tendon of the peronaeus 

 brevis may be seen extending from the tip of the lateral malleolus to the base of 

 the fifth metatarsal bone ; immediately below it is the tendon of the peronaeus longus, 

 which, as it winds round the cuboid, is obscured by the fleshy fibres of the abductor 

 digiti quinti muscle. The abductor hallucis muscle, although described along with 

 the sole, forms a fleshy pad along the medial border of the foot below the susten- 

 taculum tali. 



An incision, extending from the tuberosity of the navicular to the middle of 

 the medial border of the heel, will expose the various tendons, vessels, and nerves, 

 as they pass from the medial malleolus into the sole, beneath the abductor hallucis. 



The dorsalis pedis artery may be mapped out on the surface by drawing a line from 

 a point opposite the ankle-joint, midway between the tips of the two malleoli, to the 

 posterior end of the first interosseous space ; the vessel may be compressed against 

 the medial column of the tarsal bones. The great saphenous vein and the saphenous 

 nerve lie between the anterior border of the medial malleolus and the tendon of 

 the tibialis anterior; the small saphenous vein and the nervus suralis take the 

 same course as the tendon of the peronaeus brevis. 



The medial plantar vessels and nerves lie along the medial intermuscular septum, 

 which corresponds to a line drawn from the inferior surface of the medial 

 tubercle of the calcaneus to the interval between the first and second toes. The 

 lateral plantar vessels and nerves may be exposed by an incision along the 

 lateral intermuscular septum, which runs in a line extending from the middle of 

 the inferior surface of the heel to the fourth toe (Kocher) ; to map out the course 

 of the plantar arch, draw a line across the sole from the medial side of the base of 

 the fifth metatarsal bone to the proximal end of the first interosseous space. 



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