Leg length discrepancy (LLD) is a diagnosis that appears deceptively simple, one limb being shorter than the other. However, there is more to the apparent difference in limb length than meets the eye, and sometimes an almost imperceptible difference can be the cause of issues that arise anywhere along the lower limb or in the back. The sacrum sits between the ilium supporting the lumbar spine, and imbalance distal to this can be a source of lower back pain. Symptoms can be diverse and vague, such as complaints of lower-limb pain, intermittent backache, unilateral foot pain, or a nagging, recalcitrant running injury. Interestingly, the majority of people have some small amount of LLD, although it frequently remains asymptomatic as most can adapt and compensate for it.