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, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, China.
Surg Radiol Anat. 2021 Nov;43(11):1813-1821. doi: 10.1007/s00276-021-02819-1. Epub 2021 Aug 21.
To compare fetal and adult morphologies of the orbital muscle (OM) and to describe the detailed topographical anatomy in adults.
Using unilateral orbits from 15 near-term fetuses and 21 elderly cadavers, semiserial horizontal or sagittal paraffin sections were prepared at intervals of 20-100 µm. In addition to routine histology, we performed immunohistochemistry for smooth muscle actin.
At near term, the OM consistently extended widely from the zygomatic bone or the greater wing of the sphenoid to the maxilla or ethmoid. Thus, it was a large sheet covering the future inferior orbital fissure. In contrast, the adult OM was a thin and small muscle bundle connecting (1) the greater wing of the sphenoid to the maxilla (11/19 cadavers), (2) the lesser wing of the sphenoid to the maxilla (5/19) or the greater wing (3/19). The small OM was likely to be restricted within the greater wing (5/19 cadavers) or the maxilla (3/19). Two of these five types of OM coexisted in eight orbits. OM attachment to the lesser wing was not seen in fetuses, whereas ethmoid attachment was absent in adults.
The lesser wing attachment of the OM seemed to establish after birth. A growing common origin of the three recti was likely involved in "stealing" the near-term OM attachment from the ethmoid. The strong immunoreactivity of remnant-like OM in the elderly suggests that OM contraction is still likely to occur against the increased flow through a thin vein. However, the contraction might have no clinical significance.
比较眼眶肌（OM）的胎儿和成人形态，并描述成人的详细局部解剖结构。
使用 15 例近足月胎儿和 21 例老年尸体的单侧眼眶，每隔 20-100µm 制备半连续水平或矢状石蜡切片。除了常规组织学，我们还进行了平滑肌肌动蛋白的免疫组织化学染色。
在近足月时，OM 始终从颧骨或蝶骨大翼广泛延伸至上颌骨或筛骨，因此它是覆盖未来下眶裂的大薄片。相比之下，成人 OM 是连接（1）蝶骨大翼和上颌骨（11/19 例），（2）蝶骨小翼和上颌骨（5/19 例）或大翼（3/19 例）的薄而小的肌肉束。小 OM 可能局限于大翼（5/19 例尸体）或上颌骨（3/19 例）内。这五种类型的 OM 中有两种在八个眼眶中并存。胎儿中未见 OM 附着于小翼，而成人中无筛骨附着。
OM 的小翼附着似乎在出生后建立。三个直肌的共同起源可能涉及“窃取”近足月 OM 与筛骨的附着。老年患者残留 OM 的强烈免疫反应性表明，OM 收缩仍然可能发生在较细静脉的血流量增加的情况下。然而，这种收缩可能没有临床意义。
