Ankylosing spondylitis is a seronegative spondyloarthropathy which predominantly affects the sacroiliac joints and the spine. The spine can become very kyphotic with time. Minor trauma is sufficient to produce a fracture, because of the underlying osteoporosis and because the ankylosed segments constitute large leverage arms. These fractures are unstable because the soft tissues are ossified and also involved in the fracture. Cervical spine fractures need an immobilisation which respects the pre-injury flexion deformity. Inadvertent application of a rigid collar which forces the previously flexed cervical spine into extension may lead to neurological deterioration and even death. We report such a case in a 59-year-old male patient.