REIDER PART 218

178_Chaiter 5 Pelvis, Hip, and Thigh

Figurę 5-22. A and B, Diagram of forces across the hip during single-leg stance.

A

B

is bcaring weight on the weak limb. This results in an exaggerated up-and-down motion of the pelvis during ambulation known as Trendelenburg’s gait (Fig. 5-23). In a Trendelenburg gait, the patients pelvis sags Abductor Limp. If the abductor muscles are even weaker, further modifications of gait need to be madę to prevent the patient from falling over when bearing weight on the involved limb. By leaning over toward the side of the weightbearing limb, the patient brings his or her center of gravity closer to the femoral head. This decreases the levcrage of the patient s upper body weight and thus decreases the counterbalancing force that needs to be exerted by the abductor muscles. The correspon-ding gait abnormality, with its dramatic shift of body position, is often known as an abductor limp or abductor lurch (Fig. 5-24). When compensation of this sort is necessary in both hips, the side-to-side shifting of the patient’s upper body during ambulation is quitc dramatic.

An abductor limp may also be present in a patient with a painful hip joint but otherwise normal abductor strength. This is bccause shifting the center of gravity of the upper body to a position closer to the femoral head reduces the counterbalancing force required in the abductor muscles, thus dramatically reducing the com-pressive force across the painful hip joint. Close examina-tion of these patients reveals no evidence of a pelvic

Figurę 5-23. Trendelenburgs gait.