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Internal auditory canal: pre- and postnatal growth.
Laís Vieira Bonaldi1, Aline do Lago, Luciana C Crema
1Departments of Morphology and Otolaryngology, Federal University of São Paulo (UNIFESP-EPM), São Paulo, Brazil.
The Journal of Otolaryngology
|May 21, 2005
Summary
The internal auditory canal (IAC) changes size with age, adapting to skull growth. While adult and fetal IAC shapes are similar, their dimensions differ significantly, especially near the porus.
Area of Science:
- Anatomy
- Developmental Biology
- Otolaryngology
Background:
- The internal auditory canal (IAC) is a critical bony channel within the temporal bone.
- Understanding IAC morphology is essential for diagnosing congenital abnormalities and planning surgical interventions.
Purpose of the Study:
- To characterize the developmental changes in the size and shape of the internal auditory canal (IAC).
- To establish normative data for IAC dimensions throughout human development.
Main Methods:
- Analysis of 98 dried human temporal bones, ranging from fetal to adult specimens.
- Creation of silicone molds to accurately capture the intricate internal auditory canal geometry.
- Quantitative measurements of IAC wall lengths and diameters at the fundus, mid-portion, and porus.
Main Results:
- No significant interaural (right vs. left) differences in IAC size or shape were observed.
- IAC dimensions, particularly wall length and porus diameter, show a significant age-dependent increase.
- The fundus diameter remains relatively stable, while the mid-portion diameters exhibit developmental fluctuations.
Conclusions:
- The IAC's shape adapts to overall cranial growth during development.
- Adult and fetal IACs share similar shapes but exhibit distinct dimensional characteristics, most notably at the porus.