Vertebral Column

Question 1

Describe the composition of the 33 vertabrae.

Answer 1

7 cervical 
12 thoracic
5 lumbar
5 sacral ( fused to make sacrum )
4 coccygeal ( fuse to make coccyx )

Question 2

what are the 4 main function of the spine?

Answer 2

• support : thoracic spine and pelvis.
• protection : spinal cord, cauda equina
• movement : intervertebral discs and ligaments
• haemopoiesis : red marrow in cancellous lumbar

Question 3

Name the 3 main structured of the anterior and posterior regions of lumbar vertebra.

Answer 3

• anterior : vertebral body.

- posterior : vertebral arch and vertebral foreman.

Question 4

describe the vertebral body.

Answer 4

• 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.

Question 5

why does the size of the vertebral bodies increase superior to inferior?

Answer 5

to resist greater compressive forces as lower bears more weight than above.

Question 6

what composes the posterior region of the lumbar vertebra?

Answer 6

• 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.

Question 7

what is the anatomy of the posterior region of vertebral arch?

Answer 7

• 2 pedicles.
• 1 lamina
• 7 processes ( 2 transverse processes, 2 superior articular processes, 2 inferior articular processes, 1 spinous process )

Question 8

what does the interlocking design of facet joint mean in terms of movement?

Answer 8

• orientation allows amount of flexion, lateral flexion and rotation,
• prevents anterior displacement of vertebrae.

Question 9

describe the sacrum.

Answer 9

• 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 )

Question 10

describe the coccyx.

Answer 10

• 4 fused vertebrae.

- remnant of tail.

Question 11

name 3 types of joints found in the lumbar spine.

Answer 11

• fibrous : non mobile eg: sacroiliac joint.
• secondary cartilaginous (symphyses) : partially mobile eg: intervertebral discs.
• synovial joints : highly mobile eg: facet joints in vertebra.

Question 12

what are intervertebral discs?

Answer 12

• 70% water, 20% collagen and 10% proteoglycans.
• disc height changes with age.
• two regions nucleus pulposus centrally and annulus fibrous peripherally.

Question 13

differentiate between nucleus pulposus and annulus fibrous within intervertebral discs.

Answer 13

• 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.

Question 14

why is the spine a shock absorber?

Answer 14

forces nucleus polposus onto annulus in each direction to prevent collapse under compression resisting axial load. keeping vertebrae separate.

Question 15

what are the anterior ligaments found in vertebral column?

Answer 15

• 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.

Question 16

what are the 3 posterior ligaments in vertebral column?

Answer 16

• 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.

Question 17

compare vertebral discs and facet joints in young and elderly.

Answer 17

• 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.

Question 18

how would you describe the shape of our vertebral column during foetal development?

Answer 18

• concave anteriorly : Kyphosis.

- primary curvature which is retained in thoracic, sacral and coccygeal regions.

Question 19

how would you describe the shape of our vertebral column during infant development?

Answer 19

• 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.

Question 20

describe the structure and appearance of an adult vertebral column.

Answer 20

• 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.

Question 21

describe vertebral column with old age.

Answer 21

• secondary curvature begins to disappear and loss of disc height and osteoporotic fractures.
• primary curvature re-established.

Question 22

what causes mechanical back pain?

Answer 22

• posture and exercise.

- pressure on discs whilst slouching.

Question 23

what happens to spine with aging?

Answer 23

• 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.

Question 24

what does prolapse mean?

Answer 24

protrusion of nucleus pulposus into spinal canal leading to nerve root compression.

Question 25

what is a slipped disc and how?

Answer 25

• degeneration : disc bulge.
• prolapse : protrusion of nucleus pulposus.
• extrusion : of nucleus pulposus through annulus fibrosus within disc space.
• sequestration : pulposus breaks through and separated from main body of disc in canal.
• mostly at L4/5 or L5/S1 and usually paracentrally compressing spinal nerve roots.

Question 26

what is sciata?

Answer 26

pain caused by irritation or compression of one or more nerve roots which contribute to sciatic nerve.
diagnosed by straight leg raise test and look to replicate pain to diagnose.

nerve roots of sciatic nerve : L4, L5, S1, S2, S3.

Question 27

what dermatome is affected by L4 sciatica compression?

Answer 27

*medial aspect of lower leg.

anterior thigh, anterior knee, medial leg.

Question 28

what dermatome is affected by L5 sciatica compression?

Answer 28

• lateral aspect of lower leg.

lateral thigh, lateral leg, dorsum of foot.

Question 29

what dermatome is affected by S1 sciatica compression?

Answer 29

• lateral aspect of foot.

posterior thigh, posterior leg, heel, lateral border and sole of foot.

Question 30

name some symptoms of cauda equina syndrome?

*surgical emergency

Answer 30

• bilateral sciata
• saddle anaestheia
• painless retention of urine
• urinal and faecal incontinence
• erectile dysfunction.

Question 31

what is lumbar canal stenosis?

Answer 31

narrowing of the spinal canal, compressing the nerves traveling through the lower back into the legs, occurs in elderly.

Question 32

what is neurogenic claudication?

Answer 32

compression of nerve roots causing pain when walking, leads to ischaemia, pain and paraesthesia.

• relieved by rest and flexion of spine to enlarge canal.

Question 33

what is spondylolisthesis?

Answer 33

“spine slip”

• caused by disconnection of vertebral body from the vertebral branch.
• forward displacement.

Question 34

differentiate between parasthesia and pain.

Answer 34

pain is a shooting sensation though all transiting and passing through dermatomes of a nerve whereas parasthesia is an altered sensation felt only within corresponding dermatome of the nerve.