We evaluated 56 postmortem lumbar aortograms to study differences between subjects with and without low-back pain in the lumbar and middle sacral arteries. Twenty-two of 25 (88%) cases with back pain history had one or more missing arteries, 20 (80%) of them had narrow arteries, and 18 (72%) had developed collaterals. The corresponding figures for 22 age-matched controls were 13 (59%), 12 (55%), and 12 (55%), and for nine young (i.e., age < or = 30 years) controls two (22%), two (22%), and two (22%). The cases had on average 2.04 entirely missing and 1.32 narrow (< or = 50% in diameter) arteries, compared with the age-matched controls who had 0.82 missing (p < 0.001 for difference from cases) and 0.59 narrow arteries (p < 0.01). We conclude that insufficient arterial blood flow may be an underlying factor for low-back symptoms. Atheromatous lesions in the abdominal aorta or congenital hypoplasia of the arteries may explain the angiographic findings.