The frequency, distribution, and histological characteristics of vertebral rim lesions have been studied at D11 and L4 in 117 post-mortem spines in subjects aged 13-96 years. Only one lesion was found in patients less than 30 years, but thereafter the frequency increased with age. At least one rim was affected in the majority of patients greater than or equal to 50 years. They were found more frequently in the upper than the lower rim and they were also more common anteriorly than posteriorly. Lesions were associated with focal avulsion of the annulus in an otherwise healthy disc or with annular tears running into the rim. Rim lesions can be recognised radiographically by the presence of the vacuum phenomenon, vertebral rim sclerosis with or without a cup-shaped defect in the rim and osteophytes confined to one side of the disc. The histological appearances suggest a traumatic aetiology, and since bone is known to be supplied with pain sensitive nerve endings the lesions may be important in the general context of low back pain.