Most people have this but the difference in length is usually subtle. It’s debated in the rehab world on if it’s a cause for concern or not.
2 categories of leg length discrepancies
Functional vs Structural
Structural the leg is actually a different size from the other. Result from fracture, developmental or hip replacement are some examples.
Functional the size of the legs are the same. However the pelvis or lower back are shifted making it appear different lengths
Several different reasons for tilts and shifts in the pelvis. Postural, muscle imbalances, pain, etc
I use leg lengths as an indicator of what the pelvis is doing.
When people in my office say they feel “off” in the their lower back and/or hips usually it’s has something to do with their pelvis.
A tightness in the lower back muscle (Quadratus Lumborum) and weakening of the glute muscles is a common pattern to cause “pelvic unleveling”
Lacrosse ball work into the QL and single leg bridges to the shorter/weaker side can help with functionally and level the pelvis.