http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A temporary disc-like structure at the median atlanto-axial joint in human fetuses
Koichiro Sakanaka,Masahito Yamamoto,Hidetomo Hirouchi,Ji Hyun Kim,Gen Murakami,José Francisco Rodríguez Vázquez,Shin-ichi Abe 대한해부학회 2019 Anatomy & Cell Biology Vol.52 No.4
During observations of mid-term and late-stage fetuses, we found a joint disk-like structure at the anterior component of the median atlanto-axial joint. At mid-term, the disk-like structure was thick (0.1–0.15 mm) relative to the sizes of bones surrounding the joint. However, it did not completely separate the joint cavity, and was absent in the inferior and/or central part of the cavity. This morphology was similar to the so-called fibroadipose meniscoid of the lumbar zygapophysial joint that is usually seen in adults. In mid-term fetuses, there was evidence suggesting that a mesenchymal tissue plate was separated from a roof of the joint cavity. In late-stage fetuses, the thickness (less than 0.15 mm) was usually the same as, or less than that at mid-term, and the disk-like structure was often flexed, folded and fragmented. Therefore, in contrast to the zygapophysial meniscoid as a result of aging, the present disk-like structure was most likely a temporary product during the cavitation process. It seemed to be degenerated in late-stage fetuses and possibly also in newborns. Anomalies at the craniocervical junction such as Chiari malformations might accompany this disk-like structure at the median atlanto-axial joint even in childhood.
Ji Hyun Kim,Koichiro Sakanaka,Naomitsu Tomita,Gen Murakami,Hiroshi Abe,Shinichi Abe 대한해부학회 2017 Anatomy & Cell Biology Vol.50 No.1
Pacinian corpuscle-like structures were identified in the digital tendon sheaths and nail beds of hands obtained from eight of 12 human fetuses of gestational age 20–34 weeks (crown-rump length, 150–290 mm). The aberrant corpuscles were present in tight fibrous tissue connecting the flexor tendon sheath to the dorsal aponeurosis (138 corpuscles in the thumbs and all fingers of eight fetuses); loose fibrous tissue inside the sheath on the dorsal side of the tendon (37 corpuscles in the thumbs and all fingers of four fetuses); and the nail bed (10 clusters in the thumbs and second fingers of four smaller fetuses). The aberrant corpuscles in the tendon sheath were classified into two types: thin and short, with tightly packed lamellae, of diameter 20–40 μm and length 20–200 μm; and thick and long, with loosely packed lamellae, of diameter 70–150 μm and length 0.5–1.5 mm. The small corpuscles tended to form clusters, each containing 5–10 structures. Their similarity indicated that the tight and loose lamellae in these two types of corpuscles corresponded to typical immature and mature corpuscles, respectively, usually distributed along the palmar digital nerve. However, mature, large corpuscles were absent from the nail bed, and most aberrant corpuscles were smaller than typical corpuscles along the nerve. The aberrant corpuscles were apparently incorporated into the tendon sheath or nail bed during fetal vascular development, but they appeared to degenerate after birth due to mechanical stress from the tendon or nail.