The Hip Joint. 321 



Dislocation at the hip joint is more frequent in men 

 than in women owing to the greater exposure of the for- 

 mer to the accidents that give rise to these injuries. Of the 

 regular dislocations of the hip there, are four varieties 

 (1) On the dorsum ilii; (2) into the sciatic notch; (3) 

 on the thyroid foramen, and (4) upon the pubes. These 

 occur in the order named, thus, out of the one hundred 

 and four cases collected by Hamilton, fifty-five were on the 

 dorsum, twenty-eight into the sciatic notch, thirteen on 

 the thyroid foramen and eight on the pubes. 



1. On the Dorsum Ilii. This form of dislocation 

 generally occurs when the thigh is adducted, flexed and 

 inverted (Hamilton, Andrews) ; while Treves states, that 

 in the production of this variety of dislocation, the limb, 

 on the receipt of the injury, is, as a rule, in the position of 

 abduction and flexion. Whatever be the position of the 

 limb when the accident happens, the head of the femur 

 rests on the dorsum ilii, under or among the gluteal mus- 

 cles, while the shaft points towards the upper part of the 

 patella of the uninjured limb, and the toe of the dislo- 

 cated (2) towards the instep of the sound side. The smaller 

 external rotators are tense, or torn, the glutei muscles are 

 pushed up and stretched, the adductors are tense, while 

 the ilio-femoral or Y ligament is rigid. The limb is in 

 a state of adduction, inward rotation and slight flexion, 

 due, partly, to the bony conformation of the head of the 

 femur and of the dorsum ilii on which the head rests, but 

 chiefly to the tension of the Y ligament (Bigelow), 

 although Gunn of Chicago, considers, as the result of his 

 dissections and experiments, that the Y ligament is 

 entirely without influence in determining the deformity 

 in this form of dislocation, but that the deformity depends 

 on the tension of the anterior and inferior untorn portions 

 of the capsular ligament. 



