[Analysis of the external and internal surface of human dura mater with scanning electron microscopy]

Abstract

Introduction: In recent years several studies have raised questions about the anatomy of the human dura mater. Our objective has therefore been to examine its tridimensional structure with the aid of the scanning electron microscope.

Method: Samples were taken from 4 human cadavers (70, 72, 77 and 78 years old) between 8 and 12 hours after death. After fixing in glutaraldehyde phosphate buffer, dehydration in acetone and elimination of the acetone at the critical point, treatment with carbon and metallization with gold, the external and internal surfaces were examined.

Results: The external, or epidural, surface of the dura mater is made up of thin collagen fibers joined in bands running in different directions. The outer surface and lower layers of the dura contain elastic, interwoven fibers surpassing 2 microns in diameter. The inner surface, which is smooth and glossy, is formed of thin ribbons of arachnoids that are fused and tightly attached to the structure of the dura mater.

Conclusion: The outer surface of the dura mater consists mainly of collagen fibers which alone or in groups run in different directions: longitudinally, horizontally or obliquely, depending on the are studied. These findings contradict the classical descriptions of the dura mater as having parallel, longitudinally placed collagen fibers in the tangential plane.