Hidden Asymmetries: Leg Length Discrepancy and Breast Asymmetry in Adolescent Scoliosis and Postural Disorders—A Cross-Sectional Study

Morphological spinal alterations in adolescents, including idiopathic scoliosis (IS) and postural scoliotic attitudes (paramorphisms), may be associated with leg length discrepancy (LLD) and breast asymmetry (BA). This study aimed to assess the prevalence and characteristics of LLD and BA in adolescents with spinal paramorphisms and dysmorphisms (IS), and to explore associations between these asymmetries and spinal curve features. Methods: A cross-sectional observational study was conducted. Adolescents aged 10–18 years were included. LLD was measured clinically via direct tape measurement and, when necessary, ultrasound. BA was assessed via visual inspection. Spinal deformities were characterized via clinical and radiological examination. Results: Among the 44 participants, 26 (60%) had IS and 18 (40%) had postural scoliotic attitudes. LLD was present in 79.5% (mean 0.7 ± 0.6 cm; all mild). BA was observed in 14% of the sample. LLD was more frequent in IS (87%) than in postural scoliotic attitudes (72%). In lumbar postural curves, the shorter limb was consistently ipsilateral to the curve convexity. In IS, no consistent association was found between LLD and curve characteristics. BA was slightly more prevalent in IS (19%) than postural scoliotic attitudes (17%), with no consistent pattern relative to curve convexity. Conclusions: Mild LLD is common in adolescents with spinal asymmetries and reflects general population norms. While LLD may influence compensatory postural curves, it does not appear to affect IS curve patterns or severity. BA is more frequent in IS, but shows variable association with curve features. Considering LLD and BA prevalence in adolescents with spinal asymmetries routine assessment is warranted, though their impact on IS progression is limited.