THE HIP-JOINT. 241 



tensor vaginae feraoris. The neck of the femur is raised. 

 Rotation outwards, in which the trochanter major is 

 thrown backwards and the foot outwards, by the glutens 

 maximus and medius, pyriforrnis, obturators, and quad- 

 ratns femoris. Internal rotation., when the great tro- 

 chanter is thrown forwards and the foot inwards, by the 

 anterior fibres of the gluteus medius and the gluteus 

 minimus. 



It will be seen that the greater part of these muscles 

 are external rotators, and it has been considered that this 

 fact explains the corresponding rotation of the thigh in 

 fracture of the neck of that bone, but it is much more 

 probable that the eversion of tbe limb is due simply to 

 its own weight. External rotation, however, is of no 

 diagnostic value in fracture of the neck, unless accom- 

 panied by actual shortening of the limb. 



The trochanter major is the great lever into which are 

 inserted the rotator muscles of the hip-joint, and is sep- 

 arated from the integuments by the anterior edge of the 

 tendon of the gluteus maximus, beneath which is a large 

 bursa. Its variable position is readily seen in the seve- 

 ral movements of the hip, describing the arc of a circle, 

 owing to its continuity with the neck of the femur. 

 When the neck of the femur is fractured, the trochanter 

 major rotates in the axis of the bone, and in cases of dis- 

 location, or suspected dislocation, measurements of its 

 distance from the anterior superior iliac spine must be 

 carefully compared with similar measurements taken on 

 the opposite side of the body. The position of the tro- 

 chanter minor, which lies just below the neck, at the su- 

 perior and inferior aspect of the femur, is of importance 

 to the surgeon in performing amputation at the articu- 

 lation, as the knife is liable to be locked in it unless care 

 be taken to pass it well behind. 



