SURGICAL ANATOMY OF THE LOWER EXTREMITY. 453 



In oblique fracture of the shaft of the tibia (Fig. 270), if the fracture has taken place 

 obliquely from above, downward and forward, the fragments ride over one another, the lower 

 fragments being drawn backward and upward by the powerful action of the muscles of the 

 calf; the pointed extremity of the upper fragment projects forward immediately beneath the 

 integument, often protruding through it and rendering the fracture a compound one. If 

 the direction of the fracture is the reverse of that shown in the figure, the pointed extremity of 

 the lower fragment projects forward, riding upon the lower end of the upper one. By bending 

 the knee, which relaxes the opposing muscles, and making extension from the ankle and counter- 

 oxtension at the knee, the fragments may be brought into apposition. It is often necessary, 

 however, in compound fracture, to remove a portion of the projecting bone with the saw before 

 complete adaptation can be effected. 



Fracture of the fibula with dislocation of the foot outward (Fig. 271), commonly known as 

 " Pott's fracture," is one of the most frequent injuries of the ankle-joint. The fibula is frac- 

 tured about three inches above the ankle ; in addition to this the internal malleolus is broken 

 off, or the deltoid ligament torn through, and the end of the tibia displaced from the correspond- 

 ing surface of the astragalus. The foot is markedly everted, and the sharp edge of the upper 

 end of the fractured malleolus presses strongly against the skin ; at the same time, the heel is 

 drawn up by the muscles of the calf. This injury can generally be reduced by flexing the leg at 

 right angles with the thigh, which relaxes all the opposing muscles, and by making extension 

 from the ankle and counter-extension at the knee. 



