Department of Anatomy, College of Basic Medicine, Dalian Medical University, Dalian, Liaoning, China.
Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, Maryland, USA.
J Morphol. 2022 Aug;283(8):993-1002. doi: 10.1002/jmor.21467. Epub 2022 Jul 14.
The myodural bridge (MDB) complex are fibrous bridges that functionally connect the spinal dura mater to the suboccipital musculature. Previously, we described the maturational sequence of the MDB within the posterior atlanto-occipital interspace of the rat. The present paper describes the morphology and developmental maturation of the MDB within the posterior atlanto-axial interspace of the rat. In the present study, E18 embryonic rats, newborn rats, and adult rats were selected to evaluate the development and growth of the MDB. Within the posterior atlanto-axial interspace of the rat, the fibers of the MDB and its associated muscles, in the embryonic rat, were observed to be scarce and lightly stained. In contrast, these same structures observed in the postnatal rat were quite apparent and robustly stained. After birth, it was observed that MDB originated from the rectus capitis dorsal major muscle, extended forward and downward, and finally merged with the posterior atlanto-axial membrane. As the rats developed and matured, the observed MDB fibers passing through the posterior atlanto-axial interspace appeared denser and more organized. This study evidenced that the MDB fibers within the posterior atlanto-axial interspace were primarily composed of type I collagen fibers in the postnatal rat. By observing the suboccipital region, we are able to hypothesize that the MDB complex plays a key role in maintaining the subdural space located within the upper cervical segment during growth and development. This study provides a morphological basis for future research on the function of the MDB complex.
肌硬膜桥（MDB）复合体是一种纤维性桥梁，其功能是将脊髓硬脑膜与枕下肌肉连接起来。我们之前描述了大鼠枕骨大孔后区 MDB 的成熟顺序。本文描述了大鼠枕骨大孔后区 MDB 的形态和发育成熟。在本研究中，选择 E18 胚胎大鼠、新生大鼠和成年大鼠来评估 MDB 的发育和生长。在大鼠的枕骨大孔后区，MDB 及其相关肌肉的纤维在胚胎大鼠中观察到很少且染色较浅。相比之下，在出生后的大鼠中观察到的相同结构非常明显且染色强烈。出生后，观察到 MDB 起源于头直肌背侧大肌，向前向下延伸，最终与枕骨大孔后膜融合。随着大鼠的发育和成熟，观察到通过枕骨大孔后区的 MDB 纤维变得更加密集和有组织。这项研究表明，在出生后的大鼠中，穿过枕骨大孔后区的 MDB 纤维主要由 I 型胶原纤维组成。通过观察枕下区域，我们可以假设 MDB 复合体在生长发育过程中对维持上颈椎段硬脑膜下腔起着关键作用。本研究为 MDB 复合体功能的未来研究提供了形态学基础。
