Outline and learning objectives Anatomy of the Spinal Ligaments • Anatomy of the spinal ligaments • Intrasegmental system Filip M. Vanhoenacker • Intersegmental system • Craniocervical junction
University of Gent and Antwerp • Basic function and histology of the spinal ligaments General Hospital St-Maarten Mechelen • Understand anatomy in the interpretation of pathologic processes
Intrasegmental system Intrasegmental system
• Holds individual vertebrae together • Holds individual vertebrae together
• Ligamenta flava • Ligamenta flava • Extent: C2 - sacrum • Extent: C2 - sacrum • Connecting laminae • Connecting laminae • Protect spinal cord and nerves • Protect spinal cord and nerves
• Interspinous ligaments • Interspinous ligaments • Connecting adjoining processes • Connecting adjoining processes
• Intertransverse ligaments • Intertransverse ligaments
Intrasegmental system Intrasegmental system
• Holds individual vertebrae together • Holds individual vertebrae together
• Ligamenta flava • Ligamenta flava • Extent: C2 - sacrum • Extent: C2 - sacrum • Connecting laminae • Connecting laminae • Protect spinal cord and nerves • Protect spinal cord and nerves
• Interspinous ligaments • Interspinous ligaments • Connecting adjoining processes • Connecting adjoining processes
• Intertransverse ligaments • Intertransverse ligaments
1 Intrasegmental system Intersegmental system
• Holds individual vertebrae together • Holds multiple vertebrae together
• Ligamenta flava • Primary stabilizer of the spine • Extent: C2 - sacrum • Connecting laminae • Anterior longitudinal ligament • Protects spinal cord and nerves • Extent: C2– sacrum • Connecting annulus - body • Interspinous ligaments • Connecting adjoining processes • Posterior longitudinal ligament
• Intertransverse ligaments • Supraspinous ligaments • Insignificant bands
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Intersegmental system Intersegmental system
• Holds multiple vertebrae together • Holds multiple vertebrae together
• Primary stabilizer of the spine • Primary stabilizer of the spine
• Anterior longitudinal ligament • Anterior longitudinal ligament • Extent: C2– sacrum • Extent: C2– sacrum • Connecting annulus - body • Connecting annulus - body
• Posterior longitudinal ligament • Posterior longitudinal ligament
• Supraspinous ligaments • Supraspinous ligaments
Intersegmental system Intersegmental system
• Holds multiple vertebrae together • Holds multiple vertebrae together
• Primary stabilizer of the spine • Primary stabilizer of the spine
• Anterior longitudinal ligament • Anterior longitudinal ligament • Extent: C2– sacrum • Connecting annulus - body • Posterior longitudinal ligament • Extent: C2– sacrum • Posterior longitudinal ligament • Connecting annulus – body
• Supraspinous ligaments • Supraspinous ligaments
2 Intersegmental system Intersegmental system
• Holds multiple vertebrae together Posterior longitudinal ligament at disk space • Primary stabilizer of the spine • broad • tight adherence • Anterior longitudinal ligament Posterior longitudinal • Posterior longitudinal ligament • Extent: C2– sacrum ligament at vertebral • Connecting annulus – body body • lateral fibrovascular • Supraspinous ligaments complex (veins): loose • septum medium: tight
Courtesy F. Lecouvet. Masson 2007
Intersegmental system Intersegmental system Anatomic barrier for Anatomic barrier of spread of pathology in septum medium and the anterior epidural lateral expansions space Curtain sign on imaging Curtain sign on imaging • tumors • tumors • infections • infections • preferential lateral • preferential lateral migration of disk migration of disk extrusions extrusions • trauma: lateral • trauma: lateral fragments fragments
Intersegmental system Intersegmental system
Anatomic barrier of Anatomic barrier of septum medium and septum medium and lateral expansions lateral expansions
Curtain sign on imaging Curtain sign on imaging • tumors • tumors • infections • infections • preferential lateral • preferential lateral migration of disk migration of disk extrusions extrusions • trauma: lateral • trauma: lateral fragments fragments
3 Intersegmental system Intersegmental system
Anatomic barrier of • Holds multiple vertebrae together septum medium and lateral expansions • Primary stabilizer of the spine
Curtain sign on imaging • Anterior longitudinal ligament • tumors • infections • Posterior longitudinal ligament • preferential lateral • Supraspinous ligaments migration of disk extrusions • trauma: lateral fragments
Intersegmental system Craniocervical junction
• Holds multiple vertebrae together • Complex !
• Primary stabilizer of the spine • External ligaments
• Anterior longitudinal ligament • Anterior • Posterior • Posterior longitudinal ligament • Ligamentum nuchae
• Supraspinous ligaments •Connecting tip of spinous processes • Internal ligaments
Craniocervical junction Craniocervical junction
• Complex ! • Complex !
• Anterior external ligaments • Posterior external ligaments
• anterior longitudinal ligament • extension lig. flava • anterior atlanto-occipital • posterior atlanto-occipital • anterior atlanto-axial • posterior atlanto-axial
• Internal ligaments • Internal ligaments
4 Craniocervical junction Craniocervical junction
• Complex ! • Complex !
• Ligamentum nuchae • Ligamentum nuchae
• external occipital • external occipital protuberance protuberance • spinous process of C7 • spinous process of C7
• Internal ligaments • Internal ligaments
Craniocervical junction Craniocervical junction
• External ligaments • External ligaments
• Internal ligaments • Internal ligaments
• Anterior • Anterior •Apical (thin) •Apical (thin) •Alar (thick) •Alar (thick) • Middle • Middle • Posterior • Posterior
Craniocervical junction Craniocervical junction
• External ligaments • External ligaments
• Internal ligaments • Internal ligaments
• Anterior • Anterior • Middle: cruciform • Middle: cruciform • Transverse lig • Transverse lig • Accessory lig • Accessory lig • Superior fibers • Superior fibers • Inferior fibers • Inferior fibers
• Posterior • Posterior
5 Craniocervical junction Craniocervical junction
• External ligaments • External ligaments
• Internal ligaments • Internal ligaments • Anterior • Anterior • Middle • Middle: cruciform • Posterior • Transverse lig • tectorial membrane • Accessory lig • clivus • Superior fibers • continues as PLL • Inferior fibers
• Posterior
Craniocervical junction Craniocervical junction
• External ligaments • External ligaments
• Internal ligaments • Internal ligaments • Anterior • Anterior • Middle • Middle • Posterior • Posterior • tectorial membrane • tectorial membrane • clivus • clivus • continues as PLL • continues as PLL
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Craniocervical junction Craniocervical junction
Transverse ligament Alar ligaments Ozsarlak O.: Cervical trauma. In: Van Goethem J, et al. Spinal Imaging. Springer-Verlag. 2007; pp 279-324
6 Craniocervical junction Craniocervical junction
Transverse ligaments Transverse ligaments
Craniocervical junction Function and Histology
• Maintain mechanical stability
• Allow flexible motion
• Protection of spinal cord from excessive motion • Hyperextension • Flexion
• Function ~ histological composition (elastin-to-collagen ratio)
• high = flexible ligament (lig. flava and supraspinous lig.) • low = stiff; resist tension (e.g. ALL) Apical ligament atlanto-occipital membrane thin dural split
Function and Histology Function and Histology
Stress-vs-strain curve (from Belkoff S.M. 2007) Viscoelasticity: stiffness increases with increasing loading rate
7 Function and Histology Conclusion
Intra- and extrasegmental spinal ligaments
Craniocervical junction • External • Internal: 3 layers
Elastin-to-collagen ratio determines function • Flexibility • Resistance to tension
Knowledge of anatomy clue to correct interpretation of pathology Stiff spine: prone to ligamentous failure and neurological damage
References
• Belkoff S.M.: Biomechanics of the spine. In: Van Goethem J, et al. Spinal Imaging. Springer-Verlag. 2007; pp 87- 93
• Krakenes J.: Whiplash injuries. In: Van Goethem J, et al. Spinal Imaging. Springer-Verlag. 2007; pp 257-277
• Ozsarlak O.: Cervical trauma. In: Van Goethem J, et al. Spinal Imaging. Springer-Verlag. 2007; pp 279-324
• Netter F.H. Atlas of Human Anatomy, Ciba-Geigy
• www. primalpictures.com
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