A difference in leg length is of importance in many orthopedic and postural examinations. It is measured more accurately in the weight bearing position when the patient is standing erect.
Sighting with one's eyes and hands across the iliac crests or the gluteal muscles provides rough estimates, but these usually are too approximate for accurate measurement. A tape measure, while readily available, is neither accurate nor satisfactory to use on patients in the erect position.
A rigid fluoroscopic screen1 with a water level and a wire across the screen is accurate. However, this, besides the expensive apparatus, requires a darkroom and sufficient time for dilation of the pupils, unless a series of cases were being run consecutively.
A simple device that is equally accurate and can be made at a cost of a few dollars is described below. Measurement with this device requires only a few seconds. In addition,
Seiger HW. DEVICE FOR MEASUREMENT OF DIFFERENCES IN HEIGHT OF OPPOSITE SIDES OF BODY. JAMA. 1951;146(13):1232-1233. doi:10.1001/jama.1951.63670130012012g