The authors demonstrate five observations of aneurysmal bone cysts of the spine which were in three instances in the thoracic portion, in one instance at the C1-2 level and adjacent parts of the cranial base, in one patient the LS transition was affected with a predominating localisation in the S1 segment. The authors summarize the most important signs of aneurysmal bone cysts in the MR image incl. features common with other tumourous and non-tumourous spinal processes. They draw attention to the limitations of MRI and other methods of diagnostic imaging in typing of these spinal lesions and to difficulties in defining the borderlines between so-called primary and secondary aneurysmal bone cysts.

        Key words: MR imaging - spine, spinal canal - primary tumours and tumour-like affections of the spine - aneurysmal bone cyst - osteoblastoma, osteoid osteoma - giant cell tumour