Cervical cord stenosis. Sagittal MRI of adult with MPS I demonstrating cervical cord stenosis at C2–C4 and hypertrophied ligament, with effacement of anterior and posterior CSF spaces (red arrows). Also note the abnormal vertebrae at C7 and T1 with degenerative disc and hypertrophied ligament (yellow arrow) causing cervical-thoracic kyphosis and effacement of anterior CSF spaces.