1. Functional Anatomy of the spine Lumbo-sacral region

2. Learning Outcomes On completion of this session you will be able to: – Identify the regions of the spinal column – Describe and observe the movements of the spinal column. – Surface mark and palpate common bony landmarks of the spinal column. – Identify the major muscles acting on the spine – Use appropriate anatomical terminology – Act in a professional manner with peers.

3. Function of the spine: Supports the thoracic cage Provides attachment of muscles from the pectoral and pelvic girdles. Anchorage for powerful trunk muscles Protects spinal cord Shock absorber via the intervertebral disc and the spinal curves Flexibility of movement.

4. 7 Cervical vertebrae; facet joints are behind the transverse processes forming a weight bearing pillar, there is a foramen in the transverse processes for the passage of the vertebral artery and vein, uncovertebral joints are present on the lateral aspect of adjacent vertebral bodies C1 (the atlas) and C2 (the axis) have different configuration and articular arrangement 12 Thoracic vertebrae; Posterior anchor point for the ribs - articular costal facets on the sides of the vertebral bodies; facet on the anterior surface of the transverse process to articulate with the tubercle on the rib Long downward pointing spinous processes Narrow vertebral canal 5 Lumbar vertebrae Vertebra are larger and thicker than the other two regions Mamillary process is present on the posterior edge of the superior articular process Key features

5. Stability Intrinsic stability – Shape of the bones and joints – Ligament support Extrinsic stability – Muscular support To maintain an erect posture there should be relatively little muscle activity required and therefore less energy used. Muscle support is necessary for dynamic movement.

6. Vertebral body Pedicle Mamillary process Spinous process Transverse process Lamina Inferior articular facet Intervertebral foramen Superior articular process

7. The joints Facet joint – Synovial plane joint – Oriented vertically – allow flexion and extension some side flexion minimal rotation Inter-body joint – Secondary cartilaginous joint Together they form the “motion segment”

8. Motion segment. Consists of 2 adjacent vertebral bodies and the disc between them

9. Facet joint (Zygapophyseal) Synovial plane joints Orientation of the facets determines the movement Inter body joint (Intervertebral disc) Cartilaginous joint Superior facet Inferior facet

10. Annulus fibrosus Conccentic layers of collagen Outer fibres are attached to the outer margins of adjacent vertebral bodies Adjacent layers run in opposite directions Encapsulates the nucleus pulposus Nucleus Pulposus Semi fluid gel (gradually changes with age) Deforms under pressure (deformation resisted by the annulus fibrosus End plates Separates the disc from the vertebral body Prevents the nucleus bulging into cancellous bone of the vertebral body Common site of failure Essential for nutrition of the disc The intervertebral disc

11. Functions of IV Disc Mobility of the spinal column Shock absorption Resisting forces (compression, torsion and shear) Constantly changing in response to load

12. Ligaments Vertebral column is supported by 2 longitudinal ligaments extending its full length. – Anterior longitudinal ligament – Posterior longitudinal ligaments. Between the adjacent vertebra of the motion segment there are additional ligaments: – Supraspinous ligament – Interspinous ligament – Intertransverse ligament – Ligamentum flavum

13. Inter transverse ligament Supraspinous ligament Interspinous ligament Ligamentum flavum Superior facet Inferior facet

14. Anterior longitudinal ligament The posterior longitudinal ligament passes down the posterior surface of the vertebral bodies

15. Iliolumbar ligament Lateral lumbosacral ligament Anterior Sacroiliac ligament Sacrospinous ligament Anterior longitudinal Ligament

16. Posterior sacroiliac ligament Sacrotuberous ligament Posterior superior iliac spine

17. Muscles of the trunk Muscles extending the trunk Quadratus Lumborum Multifidus Erector spinae Muscles flexing the trunk Rectus abdominis Psoas major/minor Internal oblique* External oblique* * Also rotate the trunk Working unilaterally the muscles produce side flexion

18. Quadratus lumborum Deep to erector spinae Fibres run upwards and medially From the distal attachment on the posterior part of the iliac crest (and iliolumbar ligament) To the medial border of the inferior border Of the 12 th rib Medial border of the muscle attaches to the lateral part of the anterior surface of the Transverse process of all lumbar vertebra Multifidus Deep to erector spinae Lies in the ‘gutter’ between the spinous and transverse processes of the vertebrae at all spinal levels From the sacrum from mamillary process in the lumbar spine, the transverse processes in the thoracic region and the articular processes in the cervical region fibres pass upwards and medially to attach to the spinous processes Three layers: the deepest passes to the spinous process immediately above; the middle fibres to the second or third above and the superficial fibres Third or fourth above

19. Erector Spinae Runs the length of the vertebral column From the sacrum iliac crest and the spinous processes of L5 to T11 Divides into three columns: Medial column (spinalis) from the spinous processes L2– T11 to the spinous processes of the thoracic spine Intermediate column (longissimus) - longest and thickest to transverse processes and adjacent ribs Lateral column (iliocostalis) to the inferior border of the lower 6 ribs

20. Psoas Major (and minor) Mostly within the abdominal cavity with Relationship to the major vessels From the anterior surface of the vertebral Bodies and intervening disc and anterior Surface of the transverse process T12 – L5 Passes through the pelvis (blending with Iliacus) under inguinal ligament the to attach to the lesser trochanter

21. Enclosed within the rectus sheath From the symphysis pubis and the pubic crest To the xiphoid process and Costal cartilages of ribs 5 6 and 7 Separated by the linea alba Tendinous intersections

22. Oblique muscles From lateral 2/3 of the inguinal ligament and anterior 2/3 of the iliac crest and from the thoracolumbar fascia Fibres fan out to attach to lower four ribs then via an aponeurosis into the rectus sheath anteriorly Lowest attachment into to pubic crest Rotates the trunk to the same side Internal oblique External oblique More superficial Outer borders of the lower 8 ribs and their Costal cartilages Outer lip of the anterior 2/3 of the iliac crest Lower border of the aponeurosis forms the inguinal ligament Fibres pass downward and medially aponeurosis passes into the rectus sheath

23. Two key fascial sheaths Thoracolumbar fascia Rectus sheath

24. Linea alba External oblique Rectus abdominis Inguinal ligament

25. External oblique Transversus abdominis Internal oblique Rectus abdominis Rectal sheath