Degenerative and traumatic changes in the lower cervical spine facet joints

Objective: The aim of this study was to examine anatomical variables of the lower cervical spine facet joints with regard to age, gender, and exposure to trauma. Methods: The lower four cervical spine segments (C4-C7 included) were obtained from 40 subjects during autopsy: 12 females and 28 males (median age 35 years, range 20-49). Through an available 636 unique facets (318 joints), 1830 randomly obtained observation lines were defined. Each of these lines resembled a 3-mm-thick parasaggital slice through a facet from which 10-mu m-thick histological sections were produced and evaluated microscopically. Inter- and intraobserver agreement was tested on four randomly selected facets from each subject. Results: Significant age-, gender-, and trauma-related changes in the bone, cartilage, and soft tissues were observed, including subchondral sclerosis, fibrillation and splitting of cartilage, and cartilage length differences. Females were less affected by changes in the cartilage than males. Two synovial folds were present in all but one joint. Moderate interobserver and good intraobserver agreement were achieved. Conclusions: This study provides knowledge of the anatomy of the cervical spine facet joints. The findings support existing knowledge that males are more commonly affected by degenerative changes than females and that these changes are common from a young age. Histomorphometry confirms the presence of synovial folds in all of the facet joints. Following spinal trauma, pathological lesions may be produced in the facet joints and/or accentuate already existing pathology. The information provided in this study may have relevance for patients with neck pain.