508 CJwparfs Aniptitation 



astragalus and os calcis. A short dorsal flap is then made, the skin 

 and subjacent tissues being reflected up to the line of the trans- 

 verse tarsal joint. It is almost impossible to get the sole-flap too 

 large. 



The land-marks. The tuberosity of the scaphoid on the inner side ; 

 behind which the knife is introduced. On the outer side there is no 

 prominence showing the line of the calcaneo-cuboid joint, but that 

 articulation is surely opened by introducing the knife exactly midway 

 between the tip of the external malleolus and the tuberosity on the 

 base of the fifth metatarsal bone. The tendon of Achilles had better 

 be divided, so that the heel may be brought well down ready for sup- 

 porting the weight of the body. 



Fallacies. The mid-tarsal joint is not always easily found, the 

 surgeon opening the joint between the scaphoid and cuneiforms ; or, 

 on the outer side of the foot, plunging his knife into the hollow be- 

 tween the astragalus and os calcis, instead of into the calcaneo-cuboid 

 joint. The flap is apt to be cut too short, so that it does not cover the 

 articular surfaces ; this is especially apt to occur on the inner side, 

 where the head of the astragalus stands forth so boldly. 



The dorsal artery and the two plantars and their branches will 

 require ligation. 



The os calcis has an epiphysis into which the tendo Achillis is in- 

 serted ; this epiphysis is often detached in Syme's 

 operation. The os calcis articulates in front with 

 the cuboid ; this joint possesses a distinct synovial 

 membrane, as shown in the illustration. 



The cuboid is on the outer border of foot, between 



5 epiphysis. * " the os calcis and the fourth and fifth metatarsals. Its 



joint with the metatarsals has a separate membrane. 



The scaphoid articulates with the rounded head of the astragalus, 

 and in front with the three cuneiform bones. Its tuberosity bulges 

 into the sole on the inner side, and is the landmark behind which the 

 knife is kept in Chopart's, and also in the sub-astragaloid amputa- 

 tion. 



The cuneiform bones. The innermost has a large tuberosity 

 dipping into the sole, corresponding with that of the scaphoid. The 

 inner cuneiform articulates by a reniform facet with the base of the first 

 metatarsal, and has there a special synovial membrane. A strong 

 ligament holds the base of the second metatarsal bone against the 

 internal cuneiform. The middle and external cuneiforms articulate 

 with the second and third metatarsals ; the synovial membrane which 

 lines those joints passing back between the cuneiforms to Inbricate the 

 joints between them and the scaphoid. It also sends a prolongation 

 between the external cuneiform and the cuboid, and perhaps one be- 

 tween the scaphoid and cuboid. This arrangement is not shown in 

 the wood-cut. 



