502 SURGICAL APPLIED ANA TOMY. [Chap. xxn. 



displacement. The fibula is usually broken at a higher 

 level than the tibia, and its lower fragment follows, of 

 course, with absolute precision the corresponding 

 fragment of the larger bone. A remarkable spiral 

 fracture (fracture helicoi'de), involving the lower third 

 of the tibia, has been described by French surgeons. 

 It is associated with a more or less vertical fissure 

 that involves the ankle-joint, and with a fracture of 

 the fibula high up. MM. Leriche and Tillaux have 

 shown that this injury is due to torsion, especially to 

 some twisting of the leg while the foot is fixed. 



2. The fibula alone. Fractures of this bone in 

 its lower fourth are usually due to indirect violence, 

 Aad will be dealt with in connection with the 

 ankle-joint. When broken in any other part the 

 fracturing force is usually directly applied, the lesion 

 transverse, and the displacement insignificant, or 

 scarcely obvious. The tibia acts as an efficient splint. 



3. The tibia alone. The malleolus may be broken 

 by a blow, or the lower epiphysis separated. The 

 latter comprises the whole of the inner malleolus, 

 and the facet with which the fibula articulates. It 

 joins the shaft during the eighteenth or nineteenth 

 year. Fractures of the tibia alone are nearly always 

 due to direct violence, and whilst most common in the 

 lower third of the bone, become more rare as the 

 knee is approached. When transverse there may be 

 no visible displacement, the fibula acting as a splint. 

 Thus Mr. H. Morris mentions the case of a woman 

 who walked into and out of a hospital with a trans- 

 verse fracture of the tibia that was not detected on 

 examination, and was not indeed discovered until 

 two days after the accident. When the fracture is 

 just above the ankle the lower fragment may be moved 

 in whatever direction the foot is forced, such displace- 

 ment being resisted and limited by the inferior tibio- 

 fibular ligaments. 



