Structure of Vertebral Arch in Human and in Selected Mammals

Spondylolysis can occur in various forms and segments of human spine and has been described in humans only. The etiology of spondylolysis is not very clear (a fatigue fracture; congenital origin, multifactorial influences such as hereditary predisposition to fractures occurrence due to slight morphological spinal abnormalities). The presented study deals in morphological analysis of the interarticular region of vertebral arches of the most distresses part in humans and with the comparison of arcus vertebrae vertebral arch structure in selected species of mammals (horse, cattle, sheep, pig, dog, tiger and baboon). In contrast to the man where compact bone tissue is present in the arcus vertebrae of the last lumbar vertebrae in the region between superior and inferior articular process, in all examined mammalian species in the corresponding region of monitored vertebrae coherent cancellous bone tissue covered with a corticalis layer can be found.