Neck instability Some people with Down syndrome have neck instability (or craniovertebral instability) and it is a subject that sometimes causes worry for parents and professionals alike. The joints at the top of the spine and at the base of the skull allow us to shake and nod our heads. In people with Down syndrome, the ligaments, tissue that connects one bone to another bone thus holding a joint together, are stretchier. So joints may be looser and more flexible which can lead to slippage of the vertebrae; these are the bones that surround and protect the spinal cord. Problems can develop if a vertebra slips too far and puts pressure on the nerves in the spinal cord. This can be a gradual process or it can happen if a person is jolted suddenly such as when a whiplash injury occurs. In people with Down syndrome, the most common place for this slippage to happen is at the first and second vertebrae of the neck (known as ‘atlanto-axial instability’). Similar problems can also occur between the base of the skull and the atlas vertebrae (known as ‘atlanto-occipital instability’) although this isn’t as common as atlanto-axial instability. These two conditions are collectively known as craniovertebral instability. Sudden dislocation of the neck (such as with whip-lash injury) probably occurs more commonly in people with Down syndrome than in the rest of the population although it must be stressed that it is still very rare. A doctor suspecting that craniovertebral instability may be present and causing problems in a person with Down syndrome will probably refer that person to either an orthopaedic surgeon or a spinal neurosurgeon.