Histological and Ultrastructure of the Peripheral Nerve in Cadaveric Embalmed Specimens and in Fresh Cadavers: the Efficacy of Several Fixatives

Abstract

Objective: The study is to observe the histological structure and the ultrastructure of the peripheral nerve from cadaveric
embalmed specimens and from fresh specimens by light microscope and by transmission electron microscope. Also to study
the efficacy of the embalmed fixative to the tissue.
Methods: The peripheral nerves were dissected from the arms of five cadavers of the Department of Anatomy, Faculty of
Medicine Siriraj Hospital, Mahidol University, and from fresh cadavers. Each specimen was bisected, one put into 10%
formaldehyde which was prepared for routine H&E staining and study by light microscope. The other was put into 2.5%
glutaraldehyde, the best preserved specimen was then chosen to prepare for the TEM study.
Results: There is no significant difference between the peripheral nerves of the cadaveric embalmed and the fresh
specimens when viewed with the light microscope. On the other hand when viewed by transmission electron microscope, the
lipid part of the myelin sheath of the peripheral nerves from the cadaveric embalmed specimens are totally degenerated
while the protein part is still intact. While in the fresh specimens which are fixed by 2.5% glutaraldyhyde, there is a
complete preservation of the lipid and protein part of the myelin sheath.
Conclusion: The cadavers were fixed by excess formalin injection into the femoral artery and embalmed in formalin for at
least 1 year, this could not preserve the lipid part of the myelin sheath. However, in the fresh peripheral nerves fixed in
2.5% glutaraldehyde it could preserve the lipid and proetin parts of the myelin sheath perfectly.