Spinal subdural haematoma is a rare entity. Only a few cases have been reported, mainly in patients with coagulopathies or bleeding diathesis, and also in patients undergoing anticoagulant therapy following surgery, trauma, or lumbar puncture. Symptoms of spinal cord compression produced by spinal subdural haematoma may progress rapidly causing complete and irreversible deficits. However, rapid diagnosis and surgical intervention can result in a good functional outcome for the patient. We report on a 41-year-old woman with a normal coagulation profile who developed a spinal subdural haematoma after a minor motor vehicle accident. Although initially asymptomatic, she developed a dense quadriparesis over a 36-h period. A magnetic resonance imaging study demonstrated a subdural mass compressing the spinal cord, and at surgery a spinal subdural haematoma was found. She was discharged to an inpatient rehabilitation facility. Follow-up at 1 year showed significant improvement in motor function, but absence of posterior column function. A follow-up magnetic resonance study demonstrated widening of the spinal cord, advanced myelomalacia and a large, central, multi-loculated syrinx.