ABSTRACT
Abstract Introduction: Compression of the labyrinthine segment of the facial nerve by edema has been considered as an important pathology in the majority of the cases of idiopathic facial nerve paralysis. Hence, it is suggested that total decompression of the facial nerve should also include the labyrinthine segment by a middle fossa approach. However, the middle fossa approach requires craniotomy and temporal lobe retraction, which increases the morbidity. The labyrinthine segment of the facial nerve can also be reached through mastoidectomy. However, many ear surgeons are not familiar with this approach due to the lack of anatomical data on this surgical area. Objective: To study the anatomical limitations of decompression of the labyrinthine segment via transmastoid approach. Methods: Complete mastoidectomy was performed in six adult cadavers heads. Dissection was extended in the zygomatic root and posterior bony wall of the external auditory canal to visualize the incudomallear joint completely. The bone between tympanic segment, lateral and superior semicircular canal's ampullas and middle fossa dural plate was removed. Fine dissection was carried out over tympanic segment of the facial nerve in an anterosuperomedial direction the labyrinthine segment was reached. Results: All the mastoids were well pneumatized. Distances between the labyrinthine segment and middle fossa dura, and between the labyrinthine segment and superior semicircular canal, were 2.5 and 4.5mm on average, respectively. In addition, distances between the middle fossa dura and dome of the lateral semicircular canal, and between the middle fossa dura and tympanic segment were 4.6 mm and 4.3 mm on average, respectively. Conclusion: It is possible to expose the labyrinthine segment of the facial nerve through mastoidectomy by dissecting the bone in the area between the tympanic segment of the facial nerve, middle fossa dural plate and ampullary ends of the lateral and superior semicircular canals.
ABSTRACT
The aims of this study were to determine various morphometric measurements of auricle, to investigate asymmetry and its relation with handedness in both sexes. Main morphometric measurements of both auricles and hand preferences were determined on 200 male and 200 female healthy university students. All measurements of the auricles were larger in males than the corresponding ones in females and all the differences except earlobe widths were statistically significant. All measurements of left and right auricles were statistically significantly different in both sexes except earlobe length in males, and distance from the highest point of the auricle to the bottom of the intertragic notch and earlobe length in females. Auricle length and distance from the highest point of the auricle to the bottom of the intertragic notch had higher values at the left side and all other measurements were larger at the right side. There was no significant difference between the measurements of the corresponding auricles of the righthanded and lefthanded subjects. All measurements were larger at the right side except auricle length and distance from the highest point of the auricle to the bottom of the intertragic notch in righthanded and lefthanded subjects and all differences except earlobe length were significantly different in righthanded subjects as in the total population but in lefthanded subjects the difference of the auricle width was not significant, either. There was an apparent asymmetry of right and left auricles of normal people in the current study which should be taken in to consideration in plastic surgeries of the external ear, designing the ear devices and forensic applications of earprints.
El objetivo de este estudio fue determinar diversas mediciones morfométricas de la oreja, para investigar la asimetría y su relación con el uso de las manos en ambos sexos. Se realizaron mediciones morfométricas de los pabellones auriculares y las manos de 400 estudiantes universitarios (200 hombres y 299 mujeres). Todas las medidas de las orejas fueron mayores en los hombres y todas las diferencias, excepto las correspondientes al ancho del lóbulo auricular, fueron estadísticamente significativas. Todas las mediciones de los pabellones auriculares izquierdos y derechos presentaron diferencias estadísticamente significativas en ambos sexos, excepto en el caso de la longitud del lóbulo auricular en los hombres, y la distancia desde el punto más alto de la oreja a la parte inferior de la incisura intertrágica en el lóbulo auricular de las mujeres. La longitud de la oreja y la distancia desde el punto más alto de la misma a la parte inferior de la escotadura intertrágica tenían valores más altos en el lado izquierdo y todas las demás mediciones fueron más elevadas en el lado derecho. No hubo diferencia significativa entre las mediciones de las orejas correspondientes a los sujetos diestros y zurdos. Todas las mediciones fueron superiores en el lado derecho, excepto la longitud del pabellón auricular y la distancia desde el punto más alto de la oreja a la parte inferior de la incisura intertrágica en sujetos diestros y sujetos zurdos, y todas las diferencias, excepto la longitud del lóbulo auricular, fueron significativamente diferentes en los sujetos diestros como en la población total, pero en sujetos zurdos la diferencia de la anchura de la oreja no fue significativa. Se encontró una aparente asimetría en las orejas derecha e izquierda de los sujetos del presente estudio que debe tenerse en consideración en las cirugías plásticas del oído externo, para el diseño de los dispositivos de audición y para su aplicación en estudios forenses de las huellas de la oreja.