Atlanto-Axial Instability Among People With Down Syndrome

The muscles and ligaments which normally hold joints in a stable position may be floppy or loose in children and adolescence with Down syndrome.  This may lead to an abnormally wide range of movement at some joints.  This can affect the stability of one of the joints in the neck – the atlanto-axial joint.  This is the second highest joint in the spinal column and it lies below the base of the skull.  The normal movements at this joint are when you nod or shake your head (Pueschel 1998)

The actual bones of the joint may in some cases be poorly developed. These differences could make the joint more likely to become unstable and dislocate.

THE ATLANTO AXIAL JOINT (Normal and Abnormal)

Normal alar_ligaments atlanto-axial-instability-n
Abnormal

(Atlanto-Axial Instability among people with Down syndrome by Dr J Dennis DSMIG 2001 DSA)