Fig. 6From: A superior articular process morphology of 5th lumbar vertebra prone to screws placement failure: an anatomical study of 299 patientsIllustration demonstrating the difference between the two types of superior articular processes. In groups with low MCD (B), the superior articular processes are closer to each other and rotate inward compared to groups with normal MCD (A). At this point, the spinal canal exhibits a "clover" shapeBack to article page