Objectives: We examined histopathologic and anatomical
features of the guinea pig temporal bone and evaluated the differences
and similarities with respect to the human ear.
Study Design: Seventeen adult guinea pigs were deeply
anesthetized with pentobarbital and then decapitated. Each
temporal bone was removed and fixed in 10% formaldehyde
for a week, then decalcified in 10% formic acid for three
weeks. Paraffin-embedded specimens were serially and horizontally
sectioned at 7-micron thickness. One of every five
sections was stained with hematoxylin and eosin and studied
under light microscopy.
Results: The temporal bone consisted of a mastoid-like
process, a tympanic bulla, a tympanic ring, a petrosal segment,
and a poorly developed squamosal bone. The tympanic
bulla was a semispherical cavity surrounded by the
tympanic ring. The head of the malleus and the body of the
incus were fused, forming a malleoincudal complex. The
diameters of the tympanic sulcus and the tympanic membrane
were much greater than that of the tympanic ring,
resulting in protrusion of the external ear-canal into the
bulla. The Eustachian tube was J-shaped, lying in a bony
hiatus at the anteromedial aspect of the bulla. The inner ear
consisted of the cochlea, semicircular canals, and the
vestibule. The cochlea made 3.5 turns and projected into
the bulla. No internal auditory meatus was observed.
Conclusion: The guinea pig temporal bone was found to
have histological similarities to that of humans, making it a
good model for selected experimental studies in otology.
FREE FULL TEXTAnahtar Kelimeler: Kulak/anatomi ve histoloji; kulak, orta/anatomive histoloji; guinea pig/anatomi ve histoloji; temporal kemik/anatomi ve histoloji.