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.
Osaka M, Ishikawa A, Yamada S, Uwabe C, Imai H, Matsuda T, Yoneyama A, Takeda T, Takakuwa T, Positional changes of the ocular organs during craniofacial development, Anatomical Record, 300(12), 2107–2114, 2017 DOI: 10.1002/ar.23588
ABSTRACT
The present study aimed to describe the positional changes of the ocular organs during craniofacial development; moreover, we examined the relationships among the ocular organs and other internal structures. To do this, we traced the positions of the ocular organs in 56 human early fetal samples at different stages of development using high-resolution magnetic resonance imaging and phase-contrast X-ray computed tomography. The eyes were located on the lateral side in the ventral view at Carnegie stage (CS) 16, and then changed their positions medially during development. The eyes remained in the neurocranium until CS17. However, the eyes changed their positions medially and caudally in the viscerocranium after CS18. The positional relationship between the eyes and pituitary gland changed in the lateral view as development progressed. Specifically, they were close to each other at CS17, but moved apart during the later stages of development. These positional changes were also demonstrated quantitatively with morphometric analyses. Based on the present data, the positional changes of the eyes can be categorized into phases, as follows: Phase 1, dramatic positional changes (early fetal period until CS23); and Phase 2, mild positional changes (stabilized; early fetal period after CS23). Notably, all absolute lengths measured in the present study linearly increased as the crown-rump length increased irrespective of the phase, while features of the measured angles and ratios differentially changed in Phases 1 and 2. The present data may help improve our understanding of both the normal and abnormal development of the ocular organs and craniofacial area.
⑭ Katsube M, Yamada S, Miyazaki R, Yamaguchi Y, Makishima H, Takakuwa T, Yamamoto A, Fujii Y, Morimoto N, Ito T, Imai H, Suzuki S, Quantitation of nasal development in the early prenatal period using geometric morphometrics and MRI: A new insight into the critical period of Binder phenotype. Prenatal Diag 37: 907–915, 2017, DOI: 10.1002/pd.5106.2017
Abstract
Objectives
Disturbance of the development of the nasal septum in the early prenatal period causes congenital facial anomalies characterized by a flat nose and defects of the anterior nasal spine (ANS), such as Binder phenotype. The present research aimed to assess the development of the nasal septum and the ANS with growth in the early prenatal period.
Methods
Magnetic resonance images were obtained from 56 specimens. Mid-sagittal images were analyzed by using geometric morphometrics for the development of the nasal septum, and angle analysis was performed for the development of the ANS. Additionally, we calculated and visualized the ontogenetic allometry of the nasal septum.
Results
Our results showed that the nasal septum changed shape in the anteroposterior direction in smaller specimens, while it maintained an almost isometric shape in larger specimens. Furthermore, mathematical evidence revealed that the maturation periods of the shapes of the ANS and the nasal septum were around 12 and 14 weeks of gestation, respectively.
Conclusion
The anteroposterior development of the nasal septum is specific until 14 weeks of gestation, and it is important for nasal protrusion and the development of the ANS. Therefore, the disturbance of such development could induce low nasal deformity, including Binder phenotype.
