最近的研究证明,现在称为肌壁桥(MDB)的解剖结构将枕下肌肉组织连接到颈椎硬膜(SDM)。在人类中,MDB穿过寰枕后部和寰枢椎后部间隙。MDB在各种哺乳动物中的存在,包括飞鸟(石鸽和家蝇)已经过验证。Gentoo企鹅是海洋鸟类,每天能够潜水450次,深度达660英尺.在觅食时,这只企鹅能够达到每小时22英里的速度。Gentoo企鹅也是世界上潜水最快的鸟类。因此,本研究旨在调查Gentoo企鹅(Pygoscelispapua)中MDB的存在和特征,一个不飞行的人,可以潜水的海洋鸟。对于这项研究,解剖了六个Gentoo企鹅标本,以观察其MDB的存在和组成。还进行了组织学染色以分析Gentoo企鹅中MDB的解剖关系和特征。在这项研究中,发现Gentoo企鹅的枕下肌肉组织由背直肌炎小肌(RCDmi)和背直肌炎小肌(RCDma)组成。观察到致密的结缔组织纤维将这两个枕下肌连接到硬脊膜(SDM)。这种致密的结缔组织桥主要由I型胶原纤维组成。因此,这种企鹅的MDB似乎类似于以前在人类中观察到的MDB。本研究表明,MDB不仅存在于企鹅中,而且具有与飞行鸟类不同的独特特征。因此,这项研究促进了对无飞MDB形态特征的理解,海洋鸟类
Recent studies have evidenced that the anatomical structure now known as the myodural bridge (MDB) connects the suboccipital musculature to the cervical spinal dura mater (SDM). In humans, the MDB passes through both the posterior atlanto-occipital and the posterior atlanto-axial interspaces. The existence of the MDB in various mammals, including flying birds (Rock pigeons and Gallus domesticus) has been previously validated. Gentoo penguins are marine birds, able to make 450 dives per day, reaching depths of up to 660 feet. While foraging, this penguin is able to reach speeds of up to 22 miles per hour. Gentoo penguins are also the world\'s fastest diving birds. The present
study was therefore carried out to investigate the existence and characteristics of the MDB in Gentoo penguin (Pygoscelis papua), a non-flying, marine bird that can dive. For this
study, six Gentoo penguin specimens were dissected to observe the existence and composition of their MDB. Histological staining was also performed to analyze the anatomic relationships and characteristic of the MDB in the Gentoo penguin. In this
study, it was found that the suboccipital musculature in the Gentoo penguin consists of the rectus capitis dorsalis minor (RCDmi) muscle and rectus capitis dorsalis major (RCDma) muscle. Dense connective tissue fibers were observed connecting these two suboccipital muscles to the spinal dura mater (SDM). This dense connective tissue bridge consists of primarily type I collagen fibers. Thus, this penguin\'s MDB appears to be analogous to the MDB previously observed in humans. The present
study evidences that the MDB not only exists in penguins but it also has unique features that distinguishes it from that of flying birds. Thus, this
study advances the understanding of the morphological characteristics of the MDB in flightless, marine birds.