The lateral atlanto-axial joints and their synovial folds: an in vitro study of soft tissue injuries and fractures.

Thirty victims of blunt cervical trauma, who did not survive (acute death group), were studied at autopsy as were 11 patients who survived trauma for more than 1 month and ten controls without any known cervical trauma. All specimens were sagitally sectioned in 2-mm slices and carefully examined for injuries to the lateral parts of the atlanto-axial joints. In the acute death group, five cases showed a rupture of the joint capsule, three of these with a massive hemarthrosis. In 17 cases there was bruising around the second cervical spinal nerve. Bruising of the intra-articular synovial fold was present in 15 cases, the posterior synovial fold being most commonly affected. There were five intra-articular fractures of the lateral masses, in three cases combined with a dens fracture. In two cases a bone fragment from the fracture compressed and obliterated the lumen of the vertebral artery. The findings are discussed in relation to pain after cervical trauma.