This section is from the book "Applied Anatomy: The Construction Of The Human Body", by Gwilym G. Davis. Also available from Amazon: Applied anatomy: The construction of the human body.
The femur is usually fractured through the neck, greater trochanter, upper third of the shaft, middle of the shaft, or just above the condyles.
The signs peculiar to this fracture are due to the displacement of the fragments. Some shortening occurs in all fractures of the femur (Fig. 538). Comparative measurements to ascertain this will be of no value if the pelvis is tilted (see page 497). If by measurement the limb is shorter than the opposite one, then if the distance from the tip of the greater trochanter to the external malleolus is the same on both sides, the injury must be higher up, or in the neck.
The iliotrochanteric angle instead of being thirty degrees will be diminished or lost. The tip of the greater trochanter will be above the Roser-Nelaton line. The base of Bryant's triangle will be shorter on the injured side (Fig. 539). If the extended limb is rotated the arc described by the greater trochanter will be smaller on the injured side because the shaft rotates on its axis instead of rotating in the acetabulum. The trochanter of the injured side is usually not so prominent as on the sound side. The iliotibial band is relaxed.
Fig. 538. - Intracapsular fracture of the neck of the femur showing the shortening. The dotted line represents the outline of the normal bone.
Fig. 539. - View of the outer surface of the bones of the hip. showing Roser-Nelaton line (a d); Bryant's triangle (a b c - b c being its base); the iliotrochanteric line (a c) and iliotrochanteric angle (bac).
Shortening is well demonstrated by flexing the thighs with the patient on his back: the knee of the sound side will be found to be higher than that of the injured one.
In all fractures of the thigh the foot is placed by gravity in eversion. The rise of the greater trochanter, being nearer to the crest of the ilium, produces a slight fulness in the outer portion of Scarpa's triangle which is absent on the healthy side.
The neck is fractured in one of two places, near the head, or near the trochanter. The former is intracapsular entirely, the latter partly intracapsular and partly extracapsular. As the capsule anteriorly descends as low as the intertrochanteric line and posteriorly only half way down the neck, the high fractures are entirely intracapsular and the low fractures intracapsular in front and extracapsular behind. This causes a marked difference in healing; complete intracapsular fractures do not unite firmly, but the fractures close to the trochanters not infrequently unite firmly with resulting" good function.
Fig. 540. - Fracture of the femur at the juncture of the upper and middle thirds. Upper fragment drawn forward and outward.