OBJECT: The authors report on symptomatic patients with myelomeningocele (MMC) and lipomyelomeningocele (LMMC) who were found to have changes in their lumbosacral angle (LSA) corresponding to the onset of symptoms indicative of a tethered spinal cord. METHODS: The authors review data obtained in these two cohorts of patients and compare the LSAs measured in the perinatal period with those seen when the patients presented with symptoms of a tethered spinal cord. RESULTS: Children with LMMC, roughly one third of studied cases, were symptomatic due to a tethered spinal cord at their most recent follow-up. In children in whom the MMC was the closed form at birth, 20 of 30 had symptoms that could be indicative of a tethered spinal cord at their most recent follow-up. The LSA was altered in both groups with symptoms. CONCLUSIONS: Signs and symptoms indicative of a tethered spinal cord appear to correspond to increases in the LSA.