atlanto-axial instability

atlanto-axial instability

Abnormal mobility of the articulation of the ATLAS BONE with the AXIS BONE. This is demonstrable on X-ray by a separation of more than 3 mm, at the front, between the body of the atlas and the odontoid process of the axis. People with this abnormality should avoid activities that could bring about dislocation (subluxation) of the bones and serious risk to the spinal cord. Atlanto-axial instability is found in about 20 per cent of people with Down's syndrome because of laxity in the ligaments between the skull and the spine.
References in periodicals archive ?
Lisa was also diagnosed with Atlanto-Axial Instability (AAI) which is a complication of EDS that results from excessive movement.
The abnormalities documented in the cervical region were 8 hemivertebrae (C5 2x, C6 3x, C7 3x) followed by four dogs with atlanto-axial instability, and one dog with block vertebrae (C2-C3).
Approximately 50% of patients with atlanto-occipital fusion develop atlanto-axial instability.
3) The majority of asymptomatic individuals are neurologically intact and only some present with incidentally discovered atlanto-axial instability.
2) However, one study reported that symptomatic atlanto-axial instability can develop over time, even after a diagnosis of a 'stable' os odontoideum is made.
Cervical Paget Disease of Bone with Spinal Cord Compression due to Atlanto-Axial Instability.
C2 (between C1 and C2) typically causes peri-auricular (ear) pain and is most frequently present in rheumatoid arthritis patients with atlanto-axial instability from inflammatory joint destruction.
Additionally, individuals with Down's syndrome are at risk of Atlanto-axial instability, which is an increased mobility of the atlas and axial bones, located directly under the skull.
Atlanto-axial instability among people with Down's syndrome Web site: http://www.
Due to the high incidence of atlanto-axial instability in cases of os odontoideum, cervical flexion-extension radiographs should be obtained to document the degree of instability.