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Fetal development of the minor lung segment
Shinichi Abe1, Masahito Yamamoto1, Taku Noguchi1
1Department of Anatomy, Tokyo Dental College, Tokyo, Japan.
Anatomy & Cell Biology
|April 3, 2014
Summary
The right lung's mediobasal segmental bronchus (B7) likely develops later in fetal development, between 8 and 15 weeks. This secondary budding may be influenced by the descent of the middle lobe and inferior pulmonary vein.
Area of Science:
- Human Embryology
- Thoracic Anatomy
- Pulmonary Medicine
Background:
- The mediobasal segment (S7) of the right lung is anatomically analogous to the mammalian cardiac lobe.
- Understanding the development of the right mediobasal segmental bronchus (B7) is crucial for pulmonary anatomy and clinical relevance.
Purpose of the Study:
- To investigate the fetal development and topographical anatomy of the right mediobasal segmental bronchus (B7).
- To determine the developmental timing and potential influencing factors of B7 formation.
Main Methods:
- Examination of 15 human embryonic and fetal lungs (7-8 weeks) using serial sections.
- Analysis of 8 fetal lungs (15-18 weeks) using semiserial sections to identify B7 presence and location.
Main Results:
- B7 was absent in all 7-8 week specimens.
- B7 was present in 2 of 8 specimens (15-18 weeks), located anterior to or overriding the inferior pulmonary vein.
- B7 likely develops secondarily between 8 and 15 weeks of gestation.
Conclusions:
- The right mediobasal segmental bronchus (B7) appears to develop secondarily during mid-fetal development.
- Fetal topographical changes, such as the descent of the middle lobe and inferior pulmonary vein, may influence B7 budding.
- B7 retains clinical significance within the lung segmental system.
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