Clinical and neuroradiological data were recorded in a series of 73 spinal cord injured patients (33 in Nantes, 40 in Paris-Bicêtre) in whom a post traumatic syringomyelia (PTS) developed. These findings and a review of the literature allow to point out some of the main characteristics in such a pathology. Clinical symptoms are frequent, the commonest of them are pain and sensory loss but any alteration of the neurological status after spinal cord injury has to be considered. Magnetic resonance imaging (MRI), sagittal and axial T1 and T2 weighted images, confirms the diagnosis of syrinx (area with the same signal intensity as CSF extending beyond the site of the initial lesion at least on 2 vertebral segments). MRI allows the diagnosis when it is performed in the follow up of asymptomatic patients. So PTS is not infrequent in spinal cord injured patients, for some of them in the first year after the trauma. The highest incidence is found in patients with complete thoracic lesions. Pathophysiology and surgical management have to take into account post traumatic residual stenosis of the vertebral canal.