362 



HUMAN ANATOMY. 



is resisted, perhaps slightly, by the ligamentum teres, but chiefly by the anterior 

 margin of the acetabulum. 



Separation is followed by shortening. This may be recognized by Nelaton's line 

 (Fig. 378), by the base line of the " ilio-femoral triangle" (Bryant's) (Fig. 379), 

 or by Robson's line, which is a line dropped vertically from the anterior spine to 

 meet a transverse line drawn forward and inward from the tip of the greater tro- 

 chanter across the front of the thigh, the patient being in dorsal decubitus. 



Eversion, from the weight of the limb, is usually present. 



The toughness of the periosteum and the strength of the cartilaginous bond 

 between the neck and head in childhood may make the epiphyseal line stronger 

 than the thin neck beneath it, and fracture of the neck may therefore occur even in 

 young children or adolescents. The symptoms are very similar to those of epi- 

 physeal separation. The crepitus may be rough instead of ' ' muffled. ' ' The X-rays 

 will sometimes differentiate the two conditions. In a case of injury to the hip in a 

 young person, it is, however, probable that epiphyseal disjunction will result rather 

 than fracture of the neck; but in youth, on account of the presence of the epiphyseal 



Fig. 378. 



Fig. 379. 



Showing Nfilaton's line. 



Showing^ BrySint's triangle. 



joint and the weakness of the neck, both of these lesions are more frequent than 

 dislocation. Either of them will convert the normal obliquity of the neck to a 

 position more nearly horizontal, causing prominence and ascent of the trochanter, 

 and bringing about at once the condition known as coxa vara, which will probably 

 increase later, as whenever the angle of the neck with the shaft is diminished the 

 strain upon the former is increased. Thus, either epiphyseal separation, fracture 

 of the neck, or slight rhachitis in early childhood may result in coxa vara at the 

 period of adolescence, when the softening incident to rapid growth is taking place, 

 the body weight is increasing, — often disproportionately, — and laborious occupations 

 are frequently begun. 



The epiphysis for the greater trochanter wmies at about the nineteenth year. It 

 is easily disloc'ated, almost always from direct violence, and usually between the 

 thirteenth and eighteenth years, because that is the period of greatest exposure to 

 traumatism, and because at the latter date the epiphysis is joined to the shaft. The 

 line of junction with the shaft is on the level of the tubercle for the quadratus on the 

 posterior edge of the greater trochanter (Fig. 383). It is therefore below the level of 

 the capsule of the hip-joint and of the insertions of the glutei, obturators, pyriformis, 



