In the Barlow test, displaceability is manifested by

• A. A sudden shift of the proximal femur
• B. A clunk as the hip relocates
• C. A palpable click
• D. Pain on movement

Answer: (A)

Displaceability in this context means the hip is unstable enough that the femoral head can slip out of the acetabulum with gentle manipulation. During the Barlow maneuver, with the hip flexed and adducted, applying slight posterior pressure can cause the proximal femur to shift suddenly as the head dislocates posteriorly. Feeling that abrupt movement of the thigh indicates that the hip is dislocatable.

This differs from the sign seen with relocation (Ortolani) when the head corrects back into the socket, producing a clunk as the hip relocates. A palpable click or pain on movement is not the specific sign of displaceability the Barlow test aims to detect.