Localization of congenital tegmen tympani defects.
OBJECTIVE
This study sets out to demonstrate the normal developmental steps of the tegmen tympani and thus explains the typical localization of congenital tegmental defects.


METHODS
For this study, 79 macerated and formalin-fixed human temporal bones from 14th fetal week to adults were observed and prepared.


METHODS
Macroscopic and microscopic examination of the prenatal and postnatal changes of the tegmen tympani during its development.


METHODS
Temporal bones from 14th fetal week to adults underwent descriptive anatomic studies to understand the normal development of the tegmen tympani and to find a possible cause of its congenital defects.


RESULTS
The medial part of the tegmen tympani develops from the otic capsule during chondral ossification, thus forming the tegmental process of the petrous part. The lateral part shows membranous ossification. The tegmental process cases a temporary bony dehiscence lateral to the geniculate ganglion between the 23rd and 25th fetal week.


CONCLUSIONS
Congenital defects develop near the geniculate ganglion and seem to be due to an incomplete development of tegmental process of otic capsule. Because of that, congenital lesion of the tegmen tympani can be defined as an inner ear defect.
Department Otorhinolaryngology, Johannes Gutenberg University Medical School, Mainz, Germany. toth@hno.klinik.uni-mainz.de
Miklós
M
Tóth
Kai
K
Helling
Gábor
G
Baksa
Wolf
W
Mann
D000328:Adult; D002675:Child, Preschool; D004432:Ear, Middle / Q000002:abnormalities* / Q000254:growth & development / Q000473:pathology*; D005260:Female; D005830:Geniculate Ganglion / Q000196:embryology / Q000254:growth & development; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010012:Osteogenesis / Q000502:physiology; D011247:Pregnancy; D013701:Temporal Bone / Q000196:embryology / Q000254:growth & development / Q000473:pathology; D018058:Tympanic Membrane Perforation / Q000151:congenital / Q000473:pathology