
The increase in depth provides a larger articular surface, further improving the stability of the joint. There is a horseshoe shaped fibrocartilaginous ring around the acetabulum which increases its depth, known as the acetabular labrum. This decreases the probability of the head slipping out of the acetabulum (dislocation). It is deep, and encompasses nearly all of the head of the femur. There are a number of factors that act to increase stability of the joint. The primary function of the hip joint is to weight-bear.

It encloses a branch of the obturator artery (artery to head of femur), a minor source of arterial supply to the hip joint. It is a relatively small structure, which runs from the acetabular fossa to the fovea of the femur. The only intracapsular ligament is the ligament of head of femur. They can be divided into two groups – intracapsular and extracapsular: Tronzo, R.G.: Surgery of the Hip Joint.The ligaments of the hip joint act to increase stability. Type 5: reverse obliquity fracture, with or without greater trochanter separation.Type 4: Posterior wall exploded, neck spike displaced outside shaft.
DISPLACED INTERTROCHANTERIC FRACTURE PLUS


A1: Trochantericarea fracture, pertrochanteric simple.Philadelphia: Lippincott Williams and Wilkins, 1991 Rockwood and Green's Fractures in Adults, vol. Type II Fracture line extends downwards and outwards from the lesser trochanter (reversed obliquity/unstable).Ie: Four-fragment fracture without postero-lateral and medial support (combination of Type III and Type IV).Id: Three-fragment fracture without medial support, owing to displaced lesser trochanter or femoral arch fragment.Ic: Three-fragment fracture without posterolateral support, owing to dis- placement of greater trochanter fragment.Type I Fracture line extends upwards and outwards from the lesser trochanter (stable).
