The Mammalian Vestibular Ganglion Cells and the Myelin Sheath Surrounding Them

Abstract

Morphological findings of the vestibular ganglia of small animals and human temporal bones are reported. For light microscopy, the ganglia were fixed with Levi's solution and stained with iron—hematoxylin and/or azan. The ganglia of bats were studied with electron microscopy. For scanning laser microscopy, human temporal bones were fixed in 10% formalin, decalcified, and embedded in paraffin, then stained with laxol fast blue. The ganglia were found as nodules among the VIIIth cranial nerve. The vestibular ganglion cells were seen in myelinated and unmyelinated nerve fibres, loose collagen fibres, and capillaries, separated from each other. These cells were bipolar and spindle shaped and varied in size, in contrast to spiral ganglion cells. The cell bodies (perikarya) were surrounded by myelin sheaths. Under electron microscopy, the myelin sheath could be seen between a vestibular ganglion cell body and a Schwann cell and consisted of 3—7 major lines in bats, and of about 10 in rabbits. The structure thus depends on species. The myelin sheath of human vestibular ganglion cells was seen in Levi—azan sections with a light microscope and in LFB (and/or HE) mirror slides with a scanning laser microscope.

Key Words:

• human vestibular ganglion cell
• morphology