Idiopathic spinal cord herniation (ISCH) is a rare cause of progressive myelopathy. This condition has recently seen an increased frequency of diagnosis, possibly due to increased awareness and the use of magnetic resonance (MR) imaging. ISCH is characterised by herniation of the thoracic spinal cord through an anterior or anterolateral dural defect. Patients usually present with a Brown-Séquard-like syndrome, which is gradually progressive and may evolve into severe paraparesis. This disease has a characteristic radiological appearance, and in most cases, excellent postsurgical outcome. We report ISCH and its imaging appearance in a 31-year-old woman with classical presentation, and discuss the current concepts regarding the aetiopathogenesis, radiological features and management of the disease.