[Mechanical pathology of the spinal cord].

Syringomyelia is a cyst within the spinal cord, associated with numerous causes, most frequently combined with the Chiari abnormality. Many other causes of craniovertebral junction anomalies are described. In those cases the syringomyelia is so-called hind-brain related syringomyelia. Other dysraphic states and spinal causes of syringomyelia are spina bifida cystica, lumbar lipomas, diastematomyelia or split notochord syndrome. Mechanical causes of spinal cord compression are mostly of tumoral origin. The vast majority of spinal metastases occur extradurally and originate from carcinomas of the breast, prostate and lung. Intradural extramedullary tumours of the spine constitute two thirds of all spinal neoplasm: schwannomas and meningiomas make up approximately 90% of the total and occur in equal numbers.