REIDER PART 211

Charter 5_Pelvis, Hip, and Thigh 171

Figurę 5-9. Figure-four position brings out the contour of the adductor longus (arrow).

toward the distal tip of the right medial malleolus (Fig. 5-11). The examiner records the distance and performs the same measurement on the left lower extremity. If the lengths differ significantly, a true leg length discrepancy is present. Differences of 5 mm or less are difficult to accu-rately assess with this method of measurement.

If the ASIS to medial malleolus distances are virtu-ally identical, then the true leg lengths are equal and a functional leg length discrepancy may be present. To check for a functional leg length discrepancy, the exam-iner measures the distance from the patients umbiłicus to the tip of each medial malleolus (Fig. 5-12). If the ASIS to medial malleolus lengths are equal but the umbiłicus to medial malleolus lengths are different, a functional leg length discrepancy is present.

Błock Method. Two other methods are available for quantitating a true leg length discrepancy. In the błock method, blocks or books of various thicknesses may be

Figurę 5-10. Assessing pelvic obliquity.

placed under the shorter limb of the standing patient until the pelvic obliquity is climinated and the imaginary linę between the iliac crests is parallel to the floor. Measuring the thickness of materiał necessary to level the pelvis yields a fairly accurate estimate of the leg length discrepancy.

Visual Method. The last method for quantitating leg length discrepancy, the visual method, is particularly useful when the discrepancy is fairly smali. It is also use-ful as a screening method when no measurement devices are available. The patient lies supine on the examination