Objectives

The elephants possess the largest brain among land mammals. There were many papers discussion dealing with the development of central nervous system, the evolution of the brain or even the skill and intelligence issue of elephants. Due to the difficulty to obtain the complete elephant's brain, very few articles reported about the anatomy of the elephant's brain. The meninges of the elephant has not been studied yet. The objective of this study was giving detail of both gross and microscopic anatomy of cranial dura mater of Asian elephants (Elephas maximus).

Materials & Methods

The brains of two male Asian elephants (Elephas maximus) aged 24 and 68 years dying at the Elephant Conservation Center, Lumpang Province, Thailand were fixed in 10% neutral buffer formalin. Dissection of cranial dura meter was performed for gross study. For microscopic study, the tissue samples of the cranial dura mater was processed according to histological technique for paraffin section and stained with H&E, Massion Trichrome and Weigert staining.

Results

Cranial dura mater of 2 male Asian elephants (Elephas maximus) aged 24 yrs & 68 yrs. were studied both in gross and microscopic anatomy. The outer periosteal layer had rough surface as fibrous trabeculae. The inner meningeal layer had many small tubercles all over the surface. There were small blood vessels draining to the thick sheet of dura mater on both outer and inner layer. By observing at the cut surface of the sheet, porous appearance forming by those blood vessels could be seen in some areas. The inner meningeal layer formed the septum of Falx cerebri and Tentorium cerebelli similar to other animals. Unlike most of domestic animals, there were 2 Falx cerebelli separating each cerebellar hemisphere by running along two sides of vermis. Paraffin sections with H&E, Massion Trichrome and Weigert staining of the dura mater were examined for microscopic anatomy. Collagenous dense irregular connective tissue was the main component of the dura mater. Small blood vessels and plexus were found enormously in the outer layer but not in the inner layer. Tubercles on the inner layer were the protrusion of collagenous fibers.

Conclusion

Cranial dura mater of Asian elephant's brain, had 2 layers: the outer periosteal layer and the inner meningeal layer as same as of other mammals. There were also comprised of Falx cerebri, Tentrium cerebelli but there were 2 septum of Falx cerebelli. The tubercles on the inner meningeal layer were collagenous mass protruded from the inner surface.