Cochlear aqueduct revisited: A histological study using human fetuses.
Cavitation
Cochlear aqueduct
Cochlear vein
Human fetuses
Perilymphatic space
Scala tympani
Subarachnoid space
Journal
Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft
ISSN: 1618-0402
Titre abrégé: Ann Anat
Pays: Germany
ID NLM: 100963897
Informations de publication
Date de publication:
Apr 2024
Apr 2024
Historique:
received:
23
04
2023
revised:
04
12
2023
accepted:
20
02
2024
medline:
18
3
2024
pubmed:
29
2
2024
entrez:
28
2
2024
Statut:
ppublish
Résumé
The cochlear aqueduct (CA) connects between the perilymphatic space of the cochlea and the subarachnoid space in the posterior cranial fossa. The study aimed to examine 1) whether cavitation of the CA occurs on the subarachnoid side or the cochlear side and 2) the growth and/or degeneration of the CA and its concomitant vein. We examined paraffin-embedded histological sections from human fetuses: 15 midterm fetuses (crown-rump length or CRL, 39-115 mm) and 12 near-term fetuses (CRL, 225-328 mm). A linear mesenchymal condensation, i.e., a likely candidate of the CA anlage, was observed without the accompanying vein at 9-10 weeks. The vein appeared until 15 weeks, but it was sometimes distant from the CA. At 10-12 weeks, the subarachnoid space (or the epidural space) near the glossopharyngeal nerve rapidly protruded into the CA anlage and reached the scala tympani, in which cavitation was gradually on-going but without epithelial lining. However, CA cavitation did not to occur in the anlage. At the opening to the scala, the epithelial-like lining of the CA lost its meningeal structure. At near-term, the CA was often narrowed and obliterated. The CA develops from meningeal tissues when the cavitation of the scala begins. The latter cavitation seemed to reduce tissue stiffness leading, to meningeal protrusion. The so-called anlage of CA might be a phylogenetic remnant of the glossopharyngeal nerve branch. A course of cochlear veins appears to be determined by a rule different from the CA development.
Sections du résumé
BACKGROUND AND AIM
OBJECTIVE
The cochlear aqueduct (CA) connects between the perilymphatic space of the cochlea and the subarachnoid space in the posterior cranial fossa. The study aimed to examine 1) whether cavitation of the CA occurs on the subarachnoid side or the cochlear side and 2) the growth and/or degeneration of the CA and its concomitant vein.
METHODS
METHODS
We examined paraffin-embedded histological sections from human fetuses: 15 midterm fetuses (crown-rump length or CRL, 39-115 mm) and 12 near-term fetuses (CRL, 225-328 mm).
RESULTS
RESULTS
A linear mesenchymal condensation, i.e., a likely candidate of the CA anlage, was observed without the accompanying vein at 9-10 weeks. The vein appeared until 15 weeks, but it was sometimes distant from the CA. At 10-12 weeks, the subarachnoid space (or the epidural space) near the glossopharyngeal nerve rapidly protruded into the CA anlage and reached the scala tympani, in which cavitation was gradually on-going but without epithelial lining. However, CA cavitation did not to occur in the anlage. At the opening to the scala, the epithelial-like lining of the CA lost its meningeal structure. At near-term, the CA was often narrowed and obliterated.
CONCLUSION
CONCLUSIONS
The CA develops from meningeal tissues when the cavitation of the scala begins. The latter cavitation seemed to reduce tissue stiffness leading, to meningeal protrusion. The so-called anlage of CA might be a phylogenetic remnant of the glossopharyngeal nerve branch. A course of cochlear veins appears to be determined by a rule different from the CA development.
Identifiants
pubmed: 38417484
pii: S0940-9602(24)00028-1
doi: 10.1016/j.aanat.2024.152236
pii:
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
152236Informations de copyright
Copyright © 2024 Elsevier GmbH. All rights reserved.
Déclaration de conflit d'intérêts
Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.