大槻さんの卒論（胎児期の中耳の形成）が The Anatomical Recordに掲載されました。
中耳の耳小骨が骨化する過程、鼓室という空隙で覆われていく様子が立体的に示されました。
- CRL 37-197 mm の中耳耳小骨(MEO)の形態形成を検討
- MEOの形態は胎児と成人で類似している
- CRL150 mm 以降、MEO の大きさはほぼ変わらない
- 各MEOの骨化は単一の中心から広がる
- CRL 86 mmで、鼓室 が明確に観察可能。
31. Ohtsuki S, Ishikawa A, Yamada S, Imai H, Matsuda T, Takakuwa T, Morphogenesis of the middle ear during fetal development as observed via magnetic resonance imaging. Anat Rec 2018, 301, 757-764, doi: 10.1002/ar.23760
ABSTRACT
Recently, our research group has utilized serial histological sections to investigate the morphogenesis of the middle ear, which corresponds to the period of middle ear ossicle (MEO) cartilage formation. However, research regarding middle ear development during the post-embryonic period has been limited. In the present study, we investigated morphogenesis of the middle ear in human fetuses with a crown-rump length (CRL) between 37 and 197 mm using high-resolution magnetic resonance imaging (MRI). Our findings indicated that the morphology of the MEOs is similar during fetal development and adulthood; further, growth of the MEOs nearly ceases once a CRL of 150 mm is attained. In each MEO, ossification spreads from a single center. The malleus and Meckel’s cartilage could be discriminated in samples exhibiting a CRL of 145 mm based on differences in MRI signal intensity. In samples with a CRL of 86 mm, the tympanic cavity (TC) appeared as a thin yet distinct structure attached to the external auditory meatus at the convex surface. Only the handle of the malleus was covered by the TC, while the incus and stapes contacted the cavity at the region of articulation between the two ossicles only, even after a CRL of 145 mm had been attained. Thus, although the TC increased in both diameter and thickness, coverage did not extend across all three MEOs during the observation period. These data are expected to provide a useful standard for morphogenesis and may aid researchers in distinguishing between normal and abnormal development. Anat Rec, 301:757–764, 2018.