A functional short leg can be the result of an ipsilateral which structure?

A functional short leg can be the result of an ipsilateral which structure?

• A. Posterior ilium
• B. Anterior ilium
• C. Ischium
• D. Pubis

Answer: (A)

A functional short leg occurs when pelvic mechanics create an apparent leg-length difference rather than an actual bone length change. When the ilium on one side rotates posteriorly (posterior innominate rotation), the pelvis tilts and the acetabulum on that side sits in a position that makes the limb functionally appear shorter. This ipsilateral posterior ilium dysfunction shifts the pelvis and sacrum relationships so the standing leg on that side effectively shortens, even though the actual bone length hasn’t changed. If the ilium were rotating anteriorly, the opposite effect would happen and the leg would function as longer. The ischium or pubis can influence pelvic stability, but they don’t produce the classic functional short leg pattern on their own in the same way that an ipsilateral posterior ilium does.

A functional short leg occurs when pelvic mechanics create an apparent leg-length difference rather than an actual bone length change. When the ilium on one side rotates posteriorly (posterior innominate rotation), the pelvis tilts and the acetabulum on that side sits in a position that makes the limb functionally appear shorter. This ipsilateral posterior ilium dysfunction shifts the pelvis and sacrum relationships so the standing leg on that side effectively shortens, even though the actual bone length hasn’t changed.

If the ilium were rotating anteriorly, the opposite effect would happen and the leg would function as longer. The ischium or pubis can influence pelvic stability, but they don’t produce the classic functional short leg pattern on their own in the same way that an ipsilateral posterior ilium does.