Vertebral Column Flashcards
(34 cards)
Describe the composition of the 33 vertabrae.
7 cervical 12 thoracic 5 lumbar 5 sacral ( fused to make sacrum ) 4 coccygeal ( fuse to make coccyx )
what are the 4 main function of the spine?
- support : thoracic spine and pelvis.
- protection : spinal cord, cauda equina
- movement : intervertebral discs and ligaments
- haemopoiesis : red marrow in cancellous lumbar
Name the 3 main structured of the anterior and posterior regions of lumbar vertebra.
- anterior : vertebral body.
- posterior : vertebral arch and vertebral foreman.
describe the vertebral body.
- end plates covered in hyaline cartilage superiorly and inferiorly.
- linked to adjacent vertebral bodies via intervertebral discs.
- main weight bearing part of vertebra, 80%
- 90% cancellous bone in composition to cope with compression and carry out haemopoiesis.
why does the size of the vertebral bodies increase superior to inferior?
to resist greater compressive forces as lower bears more weight than above.
what composes the posterior region of the lumbar vertebra?
- vertebral arch that is linked to other vertebrae via articular processes ( and facet joints )
- vertebral foramen containing conus medullaris, cauda quina, meninges, epidural veins and spinal arteries.
what is the anatomy of the posterior region of vertebral arch?
- 2 pedicles.
- 1 lamina
- 7 processes ( 2 transverse processes, 2 superior articular processes, 2 inferior articular processes, 1 spinous process )
what does the interlocking design of facet joint mean in terms of movement?
- orientation allows amount of flexion, lateral flexion and rotation,
- prevents anterior displacement of vertebrae.
describe the sacrum.
- fusion of 5 sacral vertebrae.
- ilium laterally and L5 superiorly and coccyx inferiorly.
- spinal nerves exit canal via sacral foramina and sacral hiatus ( where local anaesthetic is administered )
describe the coccyx.
- 4 fused vertebrae.
- remnant of tail.
name 3 types of joints found in the lumbar spine.
- fibrous : non mobile eg: sacroiliac joint.
- secondary cartilaginous (symphyses) : partially mobile eg: intervertebral discs.
- synovial joints : highly mobile eg: facet joints in vertebra.
what are intervertebral discs?
- 70% water, 20% collagen and 10% proteoglycans.
- disc height changes with age.
- two regions nucleus pulposus centrally and annulus fibrous peripherally.
differentiate between nucleus pulposus and annulus fibrous within intervertebral discs.
- annulus fibrous surrounds nucleus polposus ( type 2 collagen ) and is made made from type 1 collagen.
- annulus made from lamellae and is avascular and aneural.
nucleus polposus remnant of notochord, high oncotic pressure, more posterior on adults and central in infants.
why is the spine a shock absorber?
forces nucleus polposus onto annulus in each direction to prevent collapse under compression resisting axial load. keeping vertebrae separate.
what are the anterior ligaments found in vertebral column?
- anterior longitudinal : anterior to vertebral body, wider than PLL, mobile over discs, prevents hyperextension.
- posterior longitudinal : throughout lumbar spine, weaker than ALL, prevent hyeprflexion, reinforce annulus centrally leading to paracentral disc prolapses.
what are the 3 posterior ligaments in vertebral column?
- supraspinous : tips of adjacent spinous processes, strong white fibrous tissue, lax in extension, prevents hyperflexion.
- interspinous : weak sheet of fibrous tissue, unite spinous processes along adjacent border, well developed only in lumbar.
- ligamentum flavum : elastin so yellow, between laminae and adjacent vertebrae, stretched during flexion of spine.
compare vertebral discs and facet joints in young and elderly.
- young can carry 80% of body weight through vertebral bodies (anterior) and 20% through facet joints ( posterior )
- elderly have disc dehydration and greater forces through facet joints ( 65% vertebral and 35% facet ) leading to osteoarthritis.
how would you describe the shape of our vertebral column during foetal development?
- concave anteriorly : Kyphosis.
- primary curvature which is retained in thoracic, sacral and coccygeal regions.
how would you describe the shape of our vertebral column during infant development?
- primary to 2 secondary curvatures.
- cervical develops first posterior concavity ( cervical lordosis ) and lifts head.
- lumbar loses primary kyphosis at crawling and lumbar lordosis secondary curvature developed in walking.
- pelvis broadens to stand vertically.
describe the structure and appearance of an adult vertebral column.
- sinusoidal profile.
- 3 Kyphoses ( anterior concavities ) in thoracic, sacrococcygeal regions retained from primary curvature.
- 2 lordoses ( posterior concavities ) in cervical and lumbar as secondary curvatures which are developmental.
*lumbar lordosis exaggerated at pregnancy.
describe vertebral column with old age.
- secondary curvature begins to disappear and loss of disc height and osteoporotic fractures.
- primary curvature re-established.
what causes mechanical back pain?
- posture and exercise.
- pressure on discs whilst slouching.
what happens to spine with aging?
- nucleus pulpolus dehydrates.
- loss of dic height so dic bulge.
- increased load stress at endplates lead to syndesmophytes :bony growth originating inside a ligament.
- increased load on facet joint lead to facet joint osteoarthritis.
what does prolapse mean?
protrusion of nucleus pulposus into spinal canal leading to nerve root compression.
