This means that the effort (force exerted by hip abductors) is positioned between the fulcrum (hip joint) and the load (upper body weight), across a lever (the neck of the femur) – see Figure 3. The hip, in this case, is a class 3 lever. There are 3 types of levers and they differ depending on where the fulcrum, load and effort are positioned relative to each other. The load is the bone itself, along with the overlying tissues. Muscle contraction provides the effort that is applied at the muscle’s insertion point on the bone.

In the human body, the joints are fulcrums, and the bones act as levers.įorces can be exerted across levers in the form of load and effort. The operation of most skeletal muscles involves leverage – using a lever to move an object.Ī lever is a rigid bar that moves on a fixed point called the fulcrum when a force is applied to it. We don’t fall because the hip abductors pull the pelvis towards the femur of the weight-bearing leg. When standing on one leg, the centre of gravity, much like the chair, shifts to the unsupported leg. The human body is the same, the centre of gravity passes midway through the body and through the pubic symphysis. Imagine a chair…when you remove a leg what happens? The chair will normally fall towards the side that had the leg removed. Unilateral positive Trendelenburg’s sign produces a lurching gait.īilaterally positive Trendelenburg’s sign produces a waddling gait. It occurs as a result of compensatory mechanisms due to the drooping pelvis. Trendelenburg’s gait involves excessive up-down motion of the pelvis whilst walking. 3 Positive signĪ positive Trendelenburg’s sign (pathological) involves sagging of the pelvis on the unsupported side due to the abductor muscles failing to stabilise the hip towards the weight-bearing femur (see Figure 2). If the patient is using your arms for support, you will feel them pressing down on one of your arms if their hip abductors are unable to support their weight.Ībductors should be sufficiently strong to keep the pelvis level during a single leg stance, but it is normal to see a slight elevation of the pelvis on the unsupported site (this is due to the abductor muscles contracting – see Figure 1). Observe carefully if the hip on the unsupported side lifts or droops. Position your hands on the patient’s iliac crests (make sure to clearly explain each of the steps and gain consent prior to doing this). When the patient lifts their left foot, the right hip abductors are being tested. When the patient lifts their right foot, the left hip abductors are being tested.

Single-leg stanceĪsk the patient to lift each foot in turn off the ground. Alternatively stand in front of the patient, with their forearms positioned on yours to support them. If the patient is comfortable to stand alone, stand behind the patient. See our hip examination guide for more details. You might also be interested in our OSCE Flashcard Collection which contains over 2000 flashcards that cover clinical examination, procedures, communication skills and data interpretation. When a patient complains of a limp, or hip pain or as part of a normal physical examination assessing gait. When would you perform Trendelenburg’s test? As a result, the pelvis will sag towards the floor while standing on the affected limb, as opposed to being lifted. If the hip abductors aren’t strong enough, or there’s pain inhibition, the patient can’t counterbalance the weight of the upper body on the affected limb. While the contralateral leg is in the air and the ipsilateral leg is on the floor (mid-stance/single leg stance), the position of the hip during this stage is important to observe when assessing the strength of the hip abductors (because all the weight of the body is being borne on one leg). 1ĭuring the foot flat phase of the gait cycle, the contralateral leg is lifted to do the heel strike.

Events of the gait cycle include heel strike foot flat push off (heel off + toe-off) and the stance and swing phases. The gait cycle is the sequence of events between the time one foot touches the ground and the time the same foot returns to the same position. Posterior fibres: extend and laterally rotate the hip OriginĪnterior fibres: flex and medially rotate the hip The hip abductors which are assessed with Trendelenburg’s test are shown in the table below. Hip abductors assessed in Trendelenburg’s test 2 The test is named after Friedrich Trendelenburg, who described the test in 1895. The aim of Trendelenburg’s test is to assess the strength of the hip abductors, specifically the gluteus medius and minimus.

Trendelenburg position