What is Atlanto-Axial Instability?

Atlanto-Axial Instability (AAI), or neck instability, is an uncommon condition but can have serious consequences. Though this condition can occur in anyone, it is more common in people with Down's Syndrome. While between 10 and 24% of people with Down's Syndrome have an unstable neck joint, only 1% develop symptoms of neck instability.

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’s syndrome, the ligaments (tissue that connects one bone to another bone thus holding a joint together) are stretchier. Therefore, joints may be looser and more flexible which can lead to slippage of the vertebrae.

Problems can develop if a vertebra slips too far and puts pressure on the nerves in the spinal cord. It can, in extreme cases, lead to sudden neck dislocation though this is rare. Slippage of the vertebrae can happen very gradually due to day-to-day wear and tear or it can happen suddenly as a result of a severe jolt or high impact.

As long as they are physically capable, a person with Down's syndrome can play any sport they want. People with Down's syndrome are often encouraged to participate in sports at a young age, to help build muscle tone, which can be naturally lower in people with Down's syndrome.1


Signs & Symptoms

Evidence suggests that most people with Down’s syndrome develop certain mild symptoms / warning signs before long-term damage takes place. These are:

  • Pain at a spot near the hard bump behind the ear
  • A stiff neck, which does not get better quickly
  • Unusual head posture
  • Changes in the way a person walks so that they may look unsteady on their feet
  • Change in a person’s ability to manipulate things with their hands


First-Aid for AAI

If a person shows any of these symptoms, they should be checked out by a doctor as soon as possible. If the symptoms come on suddenly, the person should be taken to the Emergency Department.

Adapted from:
For Families and Carers: Neck Instability. Down's Syndrome Association, UK.
1 Can People With Down's Syndrome Play Sports? Canadian Down's Syndrome Society.