What is a positive result during Barlow's Test?

In Barlow's Test, which is used to assess for hip instability or dislocation in infants, a positive result is indicated by the presence of a click or clunk. This occurs when the hip joint is gently manipulated during the test, and if the femoral head slips out of the acetabulum and then back into place, it produces a distinct sound or feeling described as a click or clunk. This positive finding suggests that there may be a degree of laxity in the hip joint, which can be indicative of developmental dysplasia of the hip (DDH).

The other options do not align with the primary purpose of Barlow's Test. A look of apprehension may signify discomfort or unease, but it does not specifically indicate a mechanical issue with the hip joint. Incomplete extension of the knee is unrelated to the hip joint assessment performed in this test. Lastly, while a popping sound could suggest hip instability, it is not the primary outcome measured in Barlow's Test; the definitive outcome is the sensation or noise associated with the hip's movement in and out of the acetabulum. Hence, the presence of a click or clunk provides a clear, clinically relevant indication of potential hip instability.