Investigation of anulus fibrosus morphology in human fetus intervertebral discs

OBJECTIVE: To determine whether the thickness of the anulus fibrosus (AF) structure of the intervertebral disc plays a role in disc herniation etiology, an important pathology. METHODS: We performed this study between February 2000 and May 2001 at Karadeniz Technical University Medical Faculty, Turkey. We used 20 human fetus cadavers with intrauterine ages between 22 and 41 weeks, taking into consideration the highest, lowest, and average frequencies, with 3 each of cervical, thoracal, and lumbar parts of the vertebral column, using a total of 9 intervertebral discs. We measured the thickness of the AF layer in each intervertebral disc in anterior, posterior, postero-dexter, and postero-sinister locations. We performed comparisons among the values obtained at the same level, and of comparative thicknesses at the same location at other levels. RESULTS: It was determined that there was no difference between the thickness of the AF in the same location at the various levels of intervertebral discs, but that at almost all levels, the thickness in posterior and anterior locations was significantly less compared to that in posterolateral locations. CONCLUSION: Anulus fibrosus thickness is not directly related to the incidence of disk hernia at different levels of the vertebral column according to the values obtained from this study.