5o8 



APPLIED ANATOMY. 



page 283). The web of the two arms is half way down the posterior surface of the 

 neck of the femur. 



Capsular Ligament. The capsule of the joint is composed of a thin sac 

 strengthened by the band-like ligaments just described. Wherever there is no rein- 

 forcing band the capsule is weak. The posterior and lower portion is weaker than 

 the anterior and upper portion. There is a weak spot between the arms of the ilio- 

 femoral ligament anteriorly, a branch of the circumflex artery usually entering here. 

 Between the pubofemoral and inner edge of the iliofemoral ligament is another weak 

 point. A bursa here separates the iliopsoas from the joint and often communicates 

 with the joint. A third weak spot is on the lower posterior part of the neck between 

 the two branches of the ischiofemoral ligament (Fig. 511). Injections into the joint 



Weak spot 



Weak portion of 

 capsule distended 

 by the injection 

 mass 



FIG. 510. The ischiofemoral or posterior Y- 

 ligament. The stem of the Y is attached at the 

 base of the tuberosity of the ischium and one 

 branch is seen going toward the greater tro- 

 chanter and the other toward the lesser, leaving a 

 weak spot between them half-way down the neck 

 of the bone. 



Fio. 511. Hip-joint distended with wax; the 

 capsule ends posteriorly half-way down the neck 

 and is seen distended by the injection material pro- 

 truding between the two arms of the ischiofemoral 

 ligament. 



protrude very markedly at this point. The weakest part of the joint is the lower 

 anterior, below the pubofemoral ligament and opposite the cotyloid notch; the 

 strongest part is the upper anterior part. 



DISLOCATIONS OF THE HIP. 



s 



Classification. Dislocations of the hip are either anterior or posterior 

 (Allis) 1 . If the innominate bone is held horizontally it will be seen that the Roser- 

 Nelaton line from the tuberosity to the anterior superior spine passes through the 

 acetabulum. It forms the apex of a wedge the two sides of which pass down, one 

 anteriorly and the other posteriorly (Fig. 512). Therefore when the head of the 



1 Dr. Oscar H. Allis has given the clearest exposition of dislocations of the hip with which we are acquainted 

 in his Gross Prize Essay entitled," An Inquiry into the Difficulties Encountered in the Reduction of Dislocations of 

 the Hip," Philadelphia, 1896. 



