A Trendelenburg's sign is a gait adopted by someone with an absent or weakened hip abductor mechanism.
During the step, instead of the pelvis being raised on the side of the lifted foot, it drops. Thus it is seen as the patient's pelvis tilting towards the lifted foot, with much flexion needed at the knee on the affected side in order for the foot to clear the ground.
Note that the lesion is on the contralateral side to the sagging hip.
A positive Trendelenburg sign is found in:
A weak abductor mechanism may also be demonstrated by Trendelenburg's test.
Last reviewed 01/2018