Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Congenital Anomaly Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan.
J Anat. 2020 Jul;237(1):166-175. doi: 10.1111/joa.13174. Epub 2020 Feb 16.
The omental bursa (OB) is a complex upper abdominal structure in adults. Its morphological complexity stems from embryonic development. Approximately 200 years ago, the first theory regarding OB development was reported, describing that the OB developed from changes in the position of the stomach and its dorsal mesentery. Thereafter, the second theory reported that the OB originated from three recesses: the right pneumato-enteric recess (rPER), hepato-enteric recess (HER), and pancreatico-enteric recess (PaER). However, the first theory, focusing on the rotation of the stomach, is still described in certain modern embryology textbooks. These two coexisting embryological theories deter the understanding of the anatomical complexity of the OB. This study aimed to unify these two theories into realistic illustrations. Approximately 10 samples per stage among Carnegie stage (CS) 13 and CS21 were microscopically observed and histological serial sections of the representative samples were aligned using the new automatic alignment method. The aligned images were segmented computationally and reconstructed into 3D models. The rPER and the HER encompassed the right half circumference of the esophagus and the stomach at CS13 and CS14, the PaER spread dorsal to the stomach and formed a discoid shape at CS15 and CS16, the infracardiac bursa (ICB) was separated by the diaphragm at CS17 and CS18, and the fourth recess, which we called the greater omental recess (GOR), extended caudally from the PaER among CS19 and CS21. The present results indicate that the fourth recess is also the origin of the OB. These two theories over 200 years can be generally unified into one embryological description indicating a new recess as the origin of the OB.
网膜囊（OB）是成人腹部的一个复杂结构。其形态学的复杂性源于胚胎发育。大约 200 年前，第一个关于 OB 发育的理论被报道，描述 OB 是由胃及其背系膜位置的变化而形成的。此后，第二个理论报道 OB 起源于三个隐窝：右胸膜-肠隐窝（rPER）、肝肠隐窝（HER）和胰肠隐窝（PaER）。然而，关注胃旋转的第一个理论仍在某些现代胚胎学教科书中描述。这两种并存的胚胎学理论阻碍了对 OB 解剖复杂性的理解。本研究旨在将这两种理论统一为现实的图示。在 Carnegie 期（CS）13 和 CS21 中，每个阶段大约有 10 个样本进行了显微镜观察，并使用新的自动对齐方法对齐了有代表性样本的组织学连续切片。对齐的图像进行了计算分割，并重建为 3D 模型。rPER 和 HER 在 CS13 和 CS14 时环绕食管和胃的右半周，PaER 向胃的背侧延伸并在 CS15 和 CS16 时形成盘状，心下囊（ICB）在 CS17 和 CS18 时被横膈膜隔开，第四个隐窝，我们称之为大网膜隐窝（GOR），在 CS19 和 CS21 时从 PaER 向尾侧延伸。目前的结果表明，第四个隐窝也是 OB 的起源。这两个 200 多年的理论可以被一般地统一为一个胚胎学描述，表明一个新的隐窝是 OB 的起源。
