THE HIP-JOIXT. 367 



tion into the sciatic notch, the head passes behind the muscle, and is therefore- prevented from 

 reaching the dorsum, in consequence of the tendon of the muscle arching over the neck of the 

 bone, and so remains in the neighborhood of the sciatic notch. Bigelow. therefore, distinguishes 

 these two forms of dislocation by describing them as dislocations backward, " above and below," 

 the Obturator iutemus. 



The ilio-femoral ligament is rarely torn in dislocations of the hip, and this fact is taken 

 advantage of by the surgeon in reducing these dislocations by manipulation. It is made to act 

 as a fulcrum to a lever, of which the long arm is the shaft of the femur, and the short arm the 

 neck of the bone. 



The hip-joint is rarely the seat of acute synovitis from injury, on account of its deep 

 position and its thick covering of soft parts. Acute inflammation may, and does, frequently 

 occur as the result of constitutional conditions, as rheumatism, pyaemia, etc. When, in these 

 cases, effusion takes place, and the joint becomes distended with fluid, the swelling is not very 

 easy to detect on account of the thickness of the capsule and the depth of the articulation. It 

 is principally to be found on the front of the joint, just internal to the ilio-femoral ligament; 

 or behind, at the lower and back part. In these two places the capsule is thinner than 

 elsewhere. Disease of the hip-joint is much more frequently of a chronic character and is 

 usually i.if a tubercular origin. It begins either in the bones or in the synovia! membrane, 

 more frequently in the former, and probably, in most cases, at the growing, highly vascular 

 in the neighborhood of the epiphysial cartilage. In this respect it differs very materially 

 from tubercular arthritis of the knee, where the disease usually commences in the synovial 

 membrane. The reasons for this are twofold : first, this part being the centre of rapid growth, 

 its nutrition is unstable and apt to pass into inflammatory action; and, secondly, great 

 strain is thrown upon it. from the frequency of falls and blows upon the hip, which causes 

 crushing of the epiphysial eartilase or the cancellous tissue in its neighborhood, with the results 

 likely to follow such an injury, fn addition to these, the depth of the joint protects it from the 

 causes of synovitis. 



In chronic hip-disease the affected limb assumes an altered position, the cause of which it 

 is important to understand. In the early stage of a typical case the limb is flexed, abducted, 

 and rotated outward. In this position all [the ligaments of the joint are relaxed : the front of 

 the capsule by flexion : the outer band of the ilio-femoral ligament by abduction ; and the 

 inner band of this ligament and the back of the capsule by rotation outward. It is, therefore, 

 the position of the greatest ease. The condition is not quite obvious at first upon examining a 

 patient. If the patient is laid in the supine position, the affected limb will be found to be 

 extended and parallel with the other. But it will be found that the pelvis is tilted downward 

 on the diseased side and the limb apparently longer than its fellow, and that the lumbar 

 spine is arched forward (lordosis). If now the thigh is abducted and flexed, the tilting down- 

 wan! and the arching forward of the pelvis disappears. The condition is thus explained. A 

 limb which is flexed and abducted is obviously useless for progression, and. in order to over- 

 come the difficulty, the patient depresses the affected side of his pelvis in order to produce 

 parallelism of his limbs, and at the same time rotates his pelvis on its transverse horizontal axis, 

 so as to direct the limb downward instead of forward. In the latter stages of the disease the 

 limb becomes flexed and abducted and inverted. This position probably depends upon muscular 

 action, at all events as regards the adduction. The Adductor muscles are supplied by the 

 obturator nerve, which also largely supplies the joint. These muscles are therefore thrown into 

 reflex action by the irritation of the peripheral terminations of this nerve in the inflamed artic- 

 ulation. Osteo-arthritis is not uncommon in the hip-joint, and it is said to be more common in 

 the male than in the female, in whom the knee-joint is more frequently affected. It is a disease 

 of middle age or more advanced period of life. 



Congenital dislocation is more commonly met with in the hip-joint than in any other articula- 

 tion. The displacement usually takes place on to the dorsum ilii. It gives rise to extreme 

 lordosis. and a waddling gait is noticed as soon as the child commences to walk. 



Excision of the hip may be required for disease or for injury, especially gunshot. It may 

 be performed either by an anterior incision or a posterior one. The former one entails less 

 interference with important structures, especially muscles, than the posterior one, but permits 

 of less efficient drainage. In these days, however, when the surgeon aims at securing 

 healing of his wound without suppuration, this second desideratum is not of so much import- 

 ance. In the operation in front the surgeon makes an incision three to four inches in length, 

 starting immediately below and external to the anterior superior spinous process of the ilium, 

 downward and inward between the Sartorius and Tensor vaginae femoris. to the neck of the 

 bone, dividing the capsule at its upper part. A narrow-bladed saw now divides the neck of the 

 femur, and the head of the bone is extracted with sequestrum forceps. All diseased tissue is 

 carefully removed with a sharp spoon or scissors, and the cavity thoroughly flushed out with a 

 hot antiseptic fluid. 



The posterior method consists in making an incision three or four inches long, commencing 

 midway between the top of the .great trochanter and the anterior superior spine, and ending 

 over the shaft, just below the trochanter. The muscles are detached from the great trochanter, 

 and the capsule opened freely. The head and neck are freed from the soft parts and the bone 

 sawn through just below the top of the trochanter with a narrow saw. The head of the bone is 

 then levered out of the acetabulum. In both operations, if the acetabulum is eroded, it must be 

 freely gouged. 



