548 



THE MUSCLES AND FASCIAE 



in any other region of the body because the tibia is such a superficial bone and is so much 

 exposed to injury. Most fractures from indirect force are oblique. 



In oblique fracture of the shaft of the tibia (Fig. 407), if the fracture has taken place obliquely 

 from above, downward and forward, the fragments override each other, 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 integu- 

 ment, often protruding through it and rendering the fracture a compound one. If the direc- 

 tion 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 counterexten- 

 sion at the knee, the fragments may be brought into apposition. 



FIG. 407. Oblique fracture of 

 the shaft of the tibia. 



FIG. 408. Fracture of the fibula, with dislocation of 

 the foot outward "Pott's fracture." 



Fracture of the fibula with dislocation of the foot outward (Fig. 408), commonly known as 

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

 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 corresponding 

 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 counterextension at the knee. 



