RT Journal Article T1 Flap valve of the heart foramen ovale revisited: macroscopic and histologic observations of human near-term fetuses A1 Suzuki, Daisuke A1 Kim, Ji Hyun A1 Shibata, Shunichi A1 Abe, Hitoshi A1 Murakami, Gen A1 Rodríguez Vázquez, José Francisco AB We assessed the flap valve of the foramen ovale (FO valve) by examining 30 hearts from human fetuses of gestational age 30-40 weeks. We dissected the hearts, examined their macroscopic morphology, and then prepared semiserial sagittal sections across the valve. Although the primary septum is expected to extend along the left atrial face, eight hearts had a superior rim of the fossa ovalis on the left atrial face that was too thick and high, so there was no smooth continuation with the valve. Moreover, three of these eight hearts each had a flap valve that was fused with a long and narrow plate arising from the caval orifice. Histological analysis indicated that 21 specimens each had a candidate primary septum that contained myocardium, although the left sinuatrial valve (LSAV) contained fibrous tissue, but little or no myocardium. In each of 17 hearts, a candidate primary septum was attached to the left atrial face of the fossa, and parts of the LSAV extended to and approached the right atrial face. However, seven of these 17 hearts each had a folded small primary septum. Another four of these 17 hearts each had an LSAV that extended widely to the fossa, and a candidate primary septum (which might be a remnant) attached to the left atrial side of the LSAV. These variations suggest that the LSAV makes a major contribution to the FO valve in some fetal hearts. Consequently, the fetal FO valve appears to have heterogeneous morphology and origin. PB Elsevier SN 0940-9602 YR 2019 FD 2019-07 LK https://hdl.handle.net/20.500.14352/109490 UL https://hdl.handle.net/20.500.14352/109490 LA eng NO Daisuke Suzuki, Ji Hyun Kim, Shunichi Shibata, Hitoshi Abe, Gen Murakami, José Francisco Rodríguez-Vázquez, Flap valve of the heart foramen ovale revisited: macroscopic and histologic observations of human near-term fetuses, Annals of Anatomy - Anatomischer Anzeiger, Volume 224, 2019, Pages 8-16, ISSN 0940-9602, https://doi.org/10.1016/j.aanat.2019.03.006. DS Docta Complutense RD 7 abr 2025