RT Journal Article
T1 Is the ultimobranchial body a reality or myth: a study using serial sections of human embryos
A1 Honkura, Yohei
A1 Yamamoto, Masahito
A1 Yoshimoto, Toshihito
A1 Rodríguez Vázquez, José Francisco
A1 Murakami, Gen
A1 Katori, Yukio
A1 Abe, Shinichi
AB Reported morphologies of the ultimobranchial body had varied between researchers: a cluster of mitotic cells, a duct-like structure and a rosette-like cell mass. To clarify the true morphology, we studied tilted horizontal sections of 20 human embryos (crown-rump length 5-18 mm; 4-6 weeks). The sections displayed a ladder-like arrangement of the second to fourth endodermal pouches and, in 5 early embryos we found the fifth pouch attached to the fifth ectodermal groove near the fourth pharyngeal arch artery. The bilateral fifth pharyngeal pouches protruded anterolaterally to form a U-shaped lumen surrounding the arytenoid swelling. The third to fifth pouches were each characterized by a pedal-shaped inferior end. We identified several types of cell clusters as candidates for the ultimobranchial body, but morphologically most of them were, to various degrees, likely to correspond to the blind end of the lower pouch when cut tangentially. Because of the topographical relation to the common carotid artery, a cyst-like structure with a cell cluster seemed to be the most likely candidate of the ultimobranchial body (a common anlage of the thymus and parathyroid). However, we were not able to deny a possibility that a certain plane cutting the pouch end incidentally provided such a cyst-like structure in sections. At any stage, the ultimobranchial body might not appear as a definite structure that is discriminated from others with routine staining. A concept of the ultimobranchial body might be biased by comparative anatomy that shows the ultimobranchial gland in adult birds and reptiles.
PB Tokyo Editional Board of Okajimas Folia Anatomica Japonica
SN 1881-1736
YR 2016
FD 2016
LK https://hdl.handle.net/20.500.14352/109707
UL https://hdl.handle.net/20.500.14352/109707
LA eng
NO Honkura, Y., Yamamoto, M., Yoshimoto, T., Rodriguez-Vazquez, J. F., Murakami, G., Katori, Y., & Abe, S. I. (2016). Is the ultimobranchial body a reality or myth: a study using serial sections of human embryos. Okajimas folia anatomica Japonica, 93(2), 29–40. https://doi.org/10.2535/ofaj.93.29
DS Docta Complutense
RD 7 abr 2025