The orthopaedic surgeon is often the first consultant to whom a patient with syringomyelia is referred. The disease is not as rare as he may suppose, but its early presenting features are very variable; if he relies solely on such familiar features as pes cavus and scoliosis, he may well miss the diagnosis. The commonest presenting symptom is pain in the head, neck, trunk or limbs; headache or neckache made worse by straining is particularly significant. A history of birth injury also may suggest the possibility of syringomyelia, especially if any spasticity subsequently worsens. Neurological features which may be diagnostic include nystagmus, dissociated sensory loss, muscle wasting, spasticity of the lower limbs or Charcot's joints. Radiographic features include erosion of the bodies of cervical vertebrae and widening of the spinal canal; if, at C5, the size of the canal exceeds that of the body by 6 millimetres in the adult, pathological dilatation is present. The presence of basilar invagination or other abnormalities of the foramen magnum, of spina bifida occulta and of scoliosis are further pointers. Thermography is a useful way of showing asymmetrical sympathetic involvement in early cases. A greater awareness of the prevalence of syringomyelia may lead to earlier diagnosis and to early operation, which appears to hold out the best hope of arresting what is all too commonly a severely disabling and progressive condition.