RT Journal Article
T1 Cavitation processes in a space filled with loose mesenchymal tissues: a comparison between the retrosternal space and the middle ear tympanic cavity in human fetuses
A1 Hayashi, Shogo
A1 Kim, Ji Hyun
A1 Jin, Zhe Wu
A1 Murakami, Gen
A1 Rodríguez Vázquez, José Francisco
A1 Abe, Shinichi
AB Background: During the expansion of the pleural cavity in early fetuses, a thick sheet of loose mesenchymal tissue (SLMT) appears between the lung bud and body wall. Subsequently, the growing lung bud invades into the SLMT and the latter becomes fragmented to disappear. To compare this with the tympanic cavity filled with loose mesenchymal tissues, the present study aimed to demonstrate the development, establishment, and breaking of the SLMT in the retrosternal space.Materials and methods: Although the retrosternal tissue was almost absent or very thin at 7 weeks, the SLMT appeared behind the manubrium sterni at 8 weeks. Accordingly, at 9-10 weeks, cavitation occurred in the SLMT to expand the pleural cavity. Therefore, the volume of SLMT was not determined by the adjacent structures such as the pericardium and sternum. Likewise, mesenchymal tissues filling the middle ear disappeared after 26 weeks.Results: There were considerable individual variations in the timing of beginning and location of the tympanic cavitation. However, in contrast to the retrosternal SLMT, the volume of the future tympanic cavity is determined by the adjacent hard tissue and tympanic membrane much earlier than the cavitation. The mesenchymal tissue carried abundant vessels in the middle ear but none or few veins in the retrosternal SLMT.Conclusions: The concept that the lung bud invades into the splanchnic mesoderm to expand the pleural cavity seems oversimplified. Mechanical stresses from the pleural cavity might induce retrosternal cavitation, while a loss in blood supply might cause tympanic cavitation.
PB Via Medica
SN 1644-3284
YR 2023
FD 2023-05-23
LK https://hdl.handle.net/20.500.14352/109201
UL https://hdl.handle.net/20.500.14352/109201
LA eng
NO Hayashi S, Kim JH, Jin ZW, Murakami G, Rodríguez-Vázquez JF, Abe S. Cavitation processes in a space filled with loose mesenchymal tissues: a comparison between the retrosternal space and the middle ear tympanic cavity in human fetuses. Folia Morphol (Warsz). 2023;82(2):332-338. doi: 10.5603/FM.a2022.0026
DS Docta Complutense
RD 21 abr 2025