Need help reading x-ray. - Knee & Hip Problems Message Board

lancell · 05-27-2008, 01:54 PM

I just had a postural x-ray to confirm whether a potential leg length discrepancy may be contributing to my scoliosis problem. X-ray indicated that "the femoral head height is 3mm higher on the right, the iliac crest height is 6mm higher on the right, the sacrum tilts inferiorly to the left by 9mm". My doctor is telling me the x-ray confirms a shorter right leg, which confuses me; if the femoral head & iliac crest are higher on the right, shouldn't that indicate that the right leg is the longer leg, not the shorter one? (Or do x-rays perhaps indicate Right or Left from the point of view of the observor, not the patient?). Please help.

jearef · 05-27-2008, 06:23 PM

Your doctor is correct. Create this mental image: you are holding a 2-foot long stick horizontally in front of you. At each end of the stick, a 3-foot long stick is hanging straight down. Now, lift up the right side of the horizontal stick. The TOP of the vertical stick on that side will be higher, but the BOTTOM of that stick will fall well short of the bottom of the other stick. Same thing with your legs.

When measuring leg length, the doctor measures from a specific point on your pelvis. The measurement referred to in your X-ray report indicates that the top of your right leg is sticking up above the reference point, and thus is functionally shorter.

Hope that makes sense.