Age changes in the lumbar spinal and intervertebral canals.

A variety of measurements of the lumbar spinal canal (SC) and intervertebral foramina (IVF) are presented and compared in two adult age groups (48 individuals aged 20-35 and 48 individuals over 60 years) in both males and females. The dimensions measured in fresh post-mortem material include: mid-sagittal (AP) and transverse diameters (TD) of the SC; height, length and greater antero-posterior (AP) width of the IVF and ligamentum flavum (LF) thickness at the lumbo-sacral level. The data show a significant decline in the SC APD in both sexes, but the SC TD increases with ageing in males while it declines with ageing in females. The IVF height decreases with ageing but its AP width increases and its length increases. The LF shows a 50% increase in thickness with ageing. These ageing changes in a 'normal' population provide the neurovascular bundle in the IVF with less 'room for manoeuvre' and support the view that minor additional pathology is more likely to lead to entrapment syndromes in the elderly than in the young.