Cho Kwang Ho, Hayashi Shogo, Jin Zhe Wu, Kim Ji Hyun, Murakami Gen, Rodríguez-Vázquez José Francisco
Department of Neurology, Institute of Wonkwang Medical Science, Wonkwang University School of Medicine and Hospital, 895, Muwang-Ro, Iksan-Si, Jeollabuk-do, 54538, Republic of Korea.
Department of Anatomy, Division of Basic Medicine, Tokai University School of Medicine, Isehara, Japan.
Surg Radiol Anat. 2023 Apr;45(4):469-478. doi: 10.1007/s00276-023-03100-3. Epub 2023 Feb 14.
Embryonic pulmonary veins (PVs) are believed to be absorbed into the left atrium (LA) to provide an adult morphology in which "four" veins drain separately into the atrium.
Serial histological sections were obtained from 27 human embryos and fetuses.
Between 5 and 6 weeks, the four PVs joined together to form a trunk-like structure (initial spatium pulmonalis) that was larger than the initial LA (two-ostia pattern). The cardiac nerves ran inferiorly along the posterior aspect of the four veins, as well as the spatium. At and until 7 weeks, the cardiac nerves were concentrated to elongate the nerve fold, and the latter separated the left PV trunk from the expanding LA (left spatium). Similarly, the right PV opened to a thick and deep LA recess (right spatium). At 8-12 weeks, depending on the growth of the LA, the opening of the left and right PVs became distant, and the spatium was elongated transversely. The left spatium was enlarged to open widely to the proper left atrium in contrast to the right spatium pushed anteriorly by the right atrium. The three-ostia pattern was transiently observed because of the lost delimitation between the left spatium and proper atrium. The myocardium was thin in the left spatium behind the left atrial nerve fold, whereas the right spatium was tube-like with a thick myocardium.
The four-ostia pattern seemed to be established at birth due to a drastically increased venous return from the lung, resulting in a flat smooth left atrial posterior wall.
胚胎期肺静脉（PVs）被认为会融入左心房（LA），以形成一种“四条”静脉分别引流至心房的成人形态。
从27例人类胚胎和胎儿获取连续组织学切片。
在5至6周时，四条肺静脉汇合形成一个主干样结构（初始肺间隙），其大于初始左心房（双开口模式）。心脏神经沿四条静脉以及该间隙的后方下行。在7周及之前，心脏神经集中以延长神经褶，后者将左肺静脉主干与扩张的左心房（左间隙）分隔开。同样，右肺静脉开口于一个厚且深的左心房隐窝（右间隙）。在8至12周时，根据左心房的生长情况，左右肺静脉的开口距离增大，间隙横向延长。与被右心房向前推的右间隙相反，左间隙扩大并广泛开口于真正的左心房。由于左间隙与真正心房之间界限消失，短暂观察到三开口模式。左心房神经褶后方的左间隙处心肌较薄，而右间隙呈管状且心肌较厚。
由于出生时肺静脉回流量急剧增加，四开口模式似乎在出生时确立，导致左心房后壁平坦光滑。
