1464 



SUKFACE AND SUKGICAL ANATOMY. 



of the tibia. The small posterior surface of the talus is felt distal and posterior to 

 the medial malleolus, at the anterior part of the hollow between it and the heel. 

 In effusions into the ankle-joint the hollows in front and behind the malleoli are 

 obliterated, and the extensor tendons are raised from the front of the joint. 



A finger's breadth distal to the tip of the medial malleolus is the sustentaculum 

 tali ; 1^ in. in front of the sustentaculum, and midway between the dorsal and 

 plantar margins of the medial aspect of the foot, is the tuberosity of the navicular 

 (the medial landmark in Chopart's amputation), which is generally visible, and 

 always distinctly palpable. The calcaneo-taloid joint lies immediately above the 

 sustentaculum, while close above it the tendon of the tibialis posterior may 

 be rendered visible, as it extends from behind the tip of the medial malleolus to 

 the tuberosity of the navicular. An inch and a half in front of the tuberosity 

 of the navicular is the joint between the first cuneiform and the first metatarsal ; 

 the ridge at the base of the first metatarsal furnishes a good guide to the articula- 

 tion. The first metatarso-phalangeal joint lies a little in front of the middle of the 

 ball of the great toe. 



A finger's breadth vertically below the tip of the lateral malleolus is the 

 trochlear process of the calcaneus, and midway between the two is the calcaneo- 

 taloid joint ; the trochlear process is, when present, a trustworthy guide to the level 

 at which the two peronsei tendons cross the lateral surface of the calcaneus. The 



Tibialis posterior 



Anterior border of distal end of tibia 

 Line of ankle-joint 



Tibialis anterior 



Head of talus 

 Tuberosity of navicular 

 Tarso-metatarsal articulation. 



First metatarso- 

 phalangeal articulation 



Posterior tibial 

 artery 



_Flexor hallucis 

 longus 



-Medial malleolus 

 "Temlo calcaneus 



lexor digitorum 

 longus' 



Sustentaculum 

 tali 



FIG. 1124. MEDIAL ASPECT OF FOOT AND ANKLE. 



greater process of the calcaneus is felt in the triangular interval between the 

 tendons of the peronseus brevis and tertius ; the calcaneo-cuboid joint the lateral 

 landmark in Chopart's amputation is placed a little in front of the mid-point 

 between the tip of the lateral malleolus and the base of the fifth metatarsal bone. 

 To open the lateral tarso-metatarsal articulations, the knife, entered behind the 

 projecting base of the fifth metatarsal bone, should be directed forwards as well as 

 medially. On the dorsum of the foot the tarsal joints are obscured by the extensor 

 tendons. The synovial layer of the ankle-joint is prolonged on to the neck of the 

 talus, and care must be taken to avoid opening the ankle-joint in performing 

 Chopart's amputation. 



The line of the tarso-metatarsal joints extends nearly 1 in. further forwards on 

 the medial than on the lateral border of the foot ; between these points the joint- 

 line takes a zigzag course on account of the second metatarsal bone extending 

 backwards between the first and third cuneiform bones. The joint between the 

 second metatarsal and second cuneiform is nearly J in. behind that between 

 the first metatarsal and first cuneiform, and nearly J in. behind that between 

 the third metatarsal and the third cuneiform. The strong transverse inter- 

 osseous ligament (Lisfrancs ligament), which connects the lateral surface of 

 the first cuneiform with the base of the second metatarsal, must be divided in 

 the tarso-metatarsal amputation of Lisfranc. In order to preserve the insertions 

 of the two tibial and the three peroneal muscles, it is advisable, when possible, 



