The cervical myodural bridge, a review of literature and clinical implications

Abstract

The role of posterior cervical musculature in sensorimotor control, cervicocephalic pain, and stabilization of the spinal cord has been recently described. Anatomical soft tissue connections which cross the cervical epidural space link suboccipital muscle fascia and dura. These myodural bridges provide passive and active anchoring of the spinal cord. They may also be involved in a dural tension monitoring system to prevent dural infolding, and maintain patency of the spinal cord. Modulation of dural tension may be initiated via a sensory reflex to muscular contractile tissues. Unanticipated movements such as hyperflexion extension injuries stimulate deep suboccipital muscles and transmit tensile forces through the bridge to the cervical dura. Due to its larger cross sectional area, the rectus capitis posterior major myodural bridge may exert greater mechanical traction on the dura than the rectus capitis posterior minor. University ethics committee approval and anatomical donor consent was obtained for this study.

Keywords: dura mater; myodural bridge; obliquus capitis inferior; rectus capitis posterior major.

Figure 1

Illustration of a dissection of the deep suboccipital region of the cervical spine. The rectus capitis posterior minor (RCPmi), rectus capitis posterior major (RCPma), and the obliquis capitis inferior (OCI) muscle fascia have communications with the dura mater via soft tissue. The encircled illustration (right) depicts a midsagittal dissection revealing the RCPma, RCPmi, and OCI muscles. The cervical myodural bridge (a) traverses the epidural space between the posterior elements of the C1 and C2 vertebrae. Both myodural structures link the suboccipital muscle fascia in to the cervical dura mater (^*).Used with permission from: Magnetic resonance imaging investigation of the atlanto-axial interspace. Clin Anat. 2013 May; 26(4):444–9. Scali et al. (Original anatomical artwork by Frank Scali, D.C., and Danny Quirk)

Figure 2

A myodural bridge (MDB) extending from the anterior fascia of the rectus capitis posterior major (RCPma) and obliquus capitis inferior (OCI) muscles, attaching on the cervical dura mater. The myodural bridge (MDB) communicates with the posterior aspect of the cervical dura mater between the C1 and C2 vertebrae. Used with permission from: The Obliquis Capitis Inferior Myodural Bridge, Clin Anat 2013 26:450 45. Pontell M, Scali F, Marshall E, Enix D. (Original anatomical artwork by Danny Quirk)

Figure 3

Hematoxylin and eosin stained tissues of left side sagittal section showing the soft tissue communication (a) between the RCPma (b) and the cervical dura mater (c) in a male cadaveric specimen. The magnified area shows the soft tissue communication at the point of contact with the dura mater (d). Used with permission from: Histological Analysis of the Connection between the Rectus Capitis Posterior Major’s myodural bridge, The Spine Journal 13 (2013) 558–563., Scali F, Pontell M, Enix D, Marshall E.

Figure 4

Sagittal section of the myodural bridge between the rectus capitis posterior major and the cervical dura mater depicting positive fluorescence after staining with antineurofilament protein antibodies. Used with permission from: Histological Analysis of the Connection between the Rectus Capitis Posterior Major’s myodural bridge, The Spine Journal 13 (2013) 558–563., Scali F, Pontell M, Enix D, Marshall E.