Occurence of complete agenesis of the sacral canal dorsal wall

Abstract

Introduction: The sacrum is a triangular bone formed by the fusion of five sacral vertebrae and is located on the pelvic region between the hip bones. Anatomical variations frequently occur on the sacral posterior part, such as the agenesis of the sacral dorsal wall that is characterized by a failure in the fusion of the sacral vertebrae laminae, making the meninges and the spinal nerves unprotected. The objective of this study was to verify the occurence of complete agenesis of the sacral dorsal wall and its clinical implications. Material and Methods: 45 sacrums were used, of unknown sex and age, from the Anatomy Laboratories of the Federal University of Sergipe and of the Tiradentes University. The length of the sacral canal was measured with the use of digital caliper. Results: The complete agenesis of the sacral dorsal wall was found, in approximately, 4.44% (2) of the cases, and the average length of the sacral canal was of about 103 mm. In one of the cases, the sacral posterior wall possessed a narrowing between S3 and S4, while the other case showed two narrowings, one being between S2 and S3, and the other between S4 and S5. Conclusion: The knowledge of the complete agenesis of the dorsal wall can help by reducing failures during the process of caudal epidural anesthesia, besides being useful to the orthopedists, as well as in pediatrics to deal with the congenital anomalies.