Spondylolisthesis
Introduction: Forward translation of one vertebra on another in the sagittal plane of the spine. Whereas spondylolysis was defect in pars interarticularis of lumbar vertebra, commonly due to repeated and increased stress on the pars interarticularis. Anatomy: Pars: It’s a region between the superior and inferior articulating facet of the vertebra. And it is known to be the weakest area in the neural arch. That is why it is susceptible to stress fracture. Pars defects: Not observed in newborns or non-ambulatory patients. Lysis ( the disintegration of a cell by rupture of the cell wall or membrane) or elongation do not occur in primates that do not have an upright bipedal gait. Presence of lumbar lordosis (unique in humans) is necessary for spondylolisthesis to occur. Classification: · Type I: Dysplastic (child) · Type II: Isthmic (5-50 yrs) · ...