PRACTICAL CONSIDERATIONS: THE HIP-JOINT. 381 



joint is nearest the surface ; and (<5) at the lower posterior part of the capsule, which 

 is also thin. 2. Tenderness over these points, — i.e., beneath the middle of Pou- 

 part's ligament and behind the trochanter. 3. Alteration in position, the femur being 

 flexed, abducted, and everted. This puts the joint in the position of greatest 

 comfort, which is that of its greatest capacity. In extension the head of the bone 

 presses against the upper anterior portion of the capsule, and the Y-ligament is 

 drawn as a dense band across the front of the joint. Flexion relaxes the superior 

 or main portion of the Y-ligament and the ilio-psoas muscle ; abduction, the outer 

 limb of the ligament and the ilio-tibial band of fascia lata ; eversion, the inner 

 limb. Fle.xion is, in its effect on tension, the most effective of these motions ; 

 eversion the least. The joint will now hold a larger quantity of fluid than when the 

 limb is in extension. 4. At this stage, to bring the limb parallel with its fellow, to 

 overcome the shortening caused by abduction, and to relieve strain, as the thigh 

 cannot be moved on the pelvis, the lumbar spine is curved with the convexity 

 towards the diseased side and the pelvis is tilted downward on that side. This is 

 the stage of apparent lengthening. The real position of the limb in abduction is 

 shown by straightening the pelvis so that a line drawn between the two anterior 

 superior spines is at right angles to the longitudinal mid-line of the body. 5. With 

 the same object of securing parallelism, — i.e., of reducing strain upon the mus- 

 cular and fibrous structures which are holding the limb in its abnormal position, 

 — the deformity caused by flexion (maintained by the ilio-psoas, which is in 

 such close relation to the front of the capsule) is met by an arching forward — 

 lordosis — of the lumbar spine. The real position of the limb in flexion is shown 

 by raising the thigh of the affected side until the lumbar curve is effaced and the 

 lumbar spines touch the surface on which the patient lies. 6. Pain in the knee is 

 often marked. It is due to the association of the nerve-supply to the two joints, 

 both being innervated from the same spinal segments, as they both receive twigs 

 from the anterior crural, obturator, sciatic, and sacral plexus. 7. Rigidity of the 

 joint is due to fixation by (a) the muscles inserted into and passing over the cap- 

 sule ; {b^ all the muscles moving the lower limb on the pelvis. Rotation is the 

 most valuable movement for diagnostic purposes because it is least likely to be 

 interfered with by extra-articular disease. For example, in abscess beneath the 

 gluteus, or in enlargement of the subgluteal bursa, flexion of the thigh is interfered 

 with ; in psoas or iliac abscess extension is limited ; in superficial disease of the 

 upper end of the shaft, or in suppuration of the bursa over the trochanter, adhe- 

 sions of the soft parts may limit both flexion and extension. 8. Muscular wasting 

 is often a very early symptom, and is then due to reflex atrophy from the associa- 

 tion — emphasized long ago by Hilton — of the nerves supplying a joint with those of 

 the muscles moving that joint ; in this instance both joint and muscles are supplied 

 by the anterior crural, the sciatic, the sacral plexus, the obturator, etc. Later, 

 atrophy of muscles may be due to disuse. The glutei and the thigh muscles are 

 those most obviously affected. The atrophy of the former aids in producing the 

 characteristic obliteration of the gluteo-femoral crease. 9. After softening of the 

 capsule and diminution of tension have occurred, the adductors draw the limb 

 inward. The lumbar spine is now curved so that the concavity is towards the 

 diseased side, thereby drawing up the pelvis on that side so as to relieve strain and 

 secure parallelism of the limb. This is the stage of apparent shortening. The 

 real position of the limb in adduction is shown by bringing the interspinous line to 

 a right angle with the longitudinal axis of the body. The adductors are supplied 

 almost exclusively by the obturator nerve, which enters largely into the supply of 

 the articulation, and act to great advantage when the capsular and ligamentous 

 resistance has partly disappeared. As the shaft and lower end of the femur move 

 inward, the head is necessarily brought more forcibly against the outer fibres of the 

 capsule near its pelvic attachment, and when they soften is partially projected from 

 the acetabulum, against the upper and outer rim of which it rests. 10. During 

 this stage the trochanter on the diseased side is often found to be nearer the middle 

 line of the body than the other trochanter. The cause of this is either absorption 

 of the head and neck of the femur or deepening of the acetabulum with sinking 

 in of the head, and the diagnosis between these may be made by rectal examina- 



