Atlantoaxial instability in Down's syndrome: a case report and review.

Down's syndrome is the most common autosomal chromosomal abnormality in humans and is associated with a number of well known clinical findings. Atlantoaxial instability is a less recognized, yet potentially significant, manifestation of Down's that has gained importance because of the widespread participation of Down's syndrome individuals in athletic events. Early recognition and appropriate management of patients with atlantoaxial instability can significantly reduce the morbidity and mortality associated with this condition and guide patients and their parents toward continued safe participation in athletics.