A 12-year-old girl with a spastic dystonic tetraparesis due to cerebral palsy showed a subacute cervical myelopathy. X-ray films of the cervical spine demonstrated a subluxation of C4 on C5. Myelography and computerized tomography of the cervical spine performed under general anesthesia demonstrated only a minimal rotation of C3 with respect to C4 and a rather narrow cervical canal. In the reported case the most important factor in the spinal cord impairment was probably the anterior-slipping of the 4th cervical vertebra. The subluxation, secondary to torsion dystonia as demonstrated by its relief during general anesthesia, very likely caused a long-standing, although intermittent, spinal cord compression.