title: The myodural bridge existing in the Nephocaena phocaenoides.
abstract: Recent studies have identified that the myodural bridge (MDB) between the rectus capitis posterior minor (RCPmi) and the cervical spinal dura mater in the posterior atlanto-occipital interspace in humans. And it was supposed that the MDB may play essential physiological roles. As a result, the MDB is possibly a highly conserved structure in the evolution of mammals. However, there is little confirmative description about the existence of the MDB in marine mammals. The objective of this study was to explore the existence and the fiber property of the MDB in the Neophocaena phocaenoides. Six cadavers of the Neophocaena phocaenoides with formalin fixation were used in this study. One was used for head and neck CT scanning and three-dimensional (3D) reconstruction and suboccipital region dissection, two were for sectional observation by P45 plastinated sheets of head and neck, and three were for histological analysis of suboccipial structures. This is the first study to demonstrate the existence of the MDB in the aquatic mammals. The rectus capitis dorsal minor (RCDmi) originated from the inferior border of the occiput and inserted into the cervical spinal dura mater. At the ventral aspect of the RCDmi, the MDB directly extended through the posterior atlanto-occipital interspace and connected with the cervical spinal dura mater which was consisted of type Ⅰ collagen. In addition, the dorsal atlanto-occipital membrane was not found in the Neophocaena phocaenoides. The tendinous myodural bridge extended from the RCDmi to the spinal dura mater through the posterior atlanto-occipital interspace in the Neophocaena phocaenoides.
authors.affiliation: The First Affiliated Hospital of Dalian Medical University, Dalian, China.
authors.forename: Pei
authors.initials: P
authors.lastname: Liu
authors.affiliation: Department of Anatomy, College of Basic Medicine, Dalian Medical University, Dalian, China.
authors.forename: Chan
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Anatomy, College of Basic Medicine, Dalian Medical University, Dalian, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Zheng
authors.affiliation: Department of Radiology, The 403 Affiliated Hospital of Chinese PLA General Hospital, Dalian, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Department of Anatomy, College of Basic Medicine, Dalian Medical University, Dalian, China.
authors.forename: Sheng-Bo
authors.initials: SB
authors.lastname: Yu
authors.affiliation: Department of Anatomy, College of Basic Medicine, Dalian Medical University, Dalian, China.|Dalian Hoffen Preservation Institution, Dalian, China.
authors.forename: Hong-Jin
authors.initials: HJ
authors.lastname: Sui
mesh_terms: D000818:Animals; D002574:Cervical Vertebrae / Q000033:anatomy & histology* / Q000502:physiology; D004388:Dura Mater / Q000033:anatomy & histology* / Q000502:physiology; D006257:Head / Q000033:anatomy & histology* / Q000502:physiology; D009333:Neck / Q000033:anatomy & histology* / Q000502:physiology; D019576:Porpoises / Q000145:classification