Vertebrae

Question 1

Vertebral Body Osteoporosis:

• How is it diagnosed?
• Why does it occur?
• Effects on bone?
• Views on x-ray? Early vs Late.
• Which type of vertebrae are most commonly affected?
• Which areas other than vertebral body are affected in the skeleton?

Answer 1

• Often picked up in routine radiographic studies
• Occurs due to imbalance between calcium resorption and bone deposition - get over all demineralisation. Normal composition of bone, just less of it.
• Causes bone to be weakened, brittle, and fragile
• Early = Vertical striping (as horizontal trabeculae are affected more). Thinned, compact bone appears relatively prominent. Later = Striping is lost and spongey bone appears transparent + less white. Vertebrae may collpase. May also see increased thoracic kyphosis.
• Thoracic vertebrae
• Neck of femur, metacarpals, radius

Question 2

Laminectomy:

• What is it?
• Purpose?

Answer 2

• Surgical process which removes spinous process + adjacent laminae. Also used to name a process where a vertebral arch is removed by transecting transverse processes.
• Purpose is to expose spinal cord (if above L2) in order to relieve pressure on it (eg. from a tumour, herniated IV disc, hypertrophy of bone).

Question 3

Dislocation of cervical vertebrae:

• Why are cervical vertebrae vulnerable to being dislocated?
• Benefit of a large vertebral canal?
• When would cervical vertebrae ‘self-reduce’?
• What do we see on X-rays and MRIs for this?

Answer 3

• Little muscle bulk around them to hold them in place. Also, articular processes are more horizontally facing so they are less interlocked.
• Vertebrae can be displaced and not always interrupt spinal cord.
• Self-reduces when facet-jumping has NOT occurred.
• X-rays do not show self-reduced dislocations, but MRIs will show the soft tissue damage.

Question 4

Fracture-Dislocation of Atlas:

• How does the shape alter the movements?
• What else could break/rupture if force is enough?
• Common name?

Answer 4

• Wedge shape of lateral masses compressed against occipital condyles + axis causes the masses to be driven apart. This causes a fracture of 1 or both anterior + posterior arches.
• Transverse ligament could break
• Jefferson’s Fracture

Question 5

Fracture-Dislocation of Axis:

• Which part of the vertebral arch of C2 normally breaks?
• Other name for the condition?
• Common cause?
• Which conditions can arise from injury to spinal cord and/or brain stem?
• What other structure can also break on C2, quite commonly?

Answer 5

• Pars Interarticularis (column of bone between articular surfaces)
• Traumatic spondylolysis of C2 (if at pars interarticularis). Hangman’s fracture if due to excessive hyperextension of head on neck.
• Quadriplegia or death
• Dens/Odontoid process.

Question 6

Lumbar Spinal Stenosis:

• Which part of the vertebrae is narrowed?
• Aetiology?
• Complications?
• Treatment?
• What can worsen it?

Answer 6

• Vertebral foramen
• Hereditary anomaly
• Makes them more likely to suffer from age-related degenerative changes (eg. IV disc bulging). Can also cause compression of 1 or more spinal nerve roots occupying inferior vertebral canal.
• Surgical treatment can be via a laminectomy.
• Worsened by IV disc protrusion, arthritic proliferation, and ligamentous degeneration (all compromise an already limited vertebral canal).

Question 7

Cervical Ribs:

• What is this?
• What consequences could arise from an extra rib?

Answer 7

• Rather than costal facets for ribs only being on thoracic vertebrae, there can occasionally be costal facets on C7 (on the transverse process - anterior to thoracic foramen).
• An extra rib (or a fibrous connection) from its tip to 1st thoraccic rib may elevate and place pressure on structures that emerge from superior thoracic aperture (eg. subclavian artery, brachial plexus inferior trunk) and can cause thoracic outlet syndrome.

Question 8

Caudal Equina Anaesthesia:

• Where is the anaesthetic injected?
• How can we alter the amount of spread of the anaesthetic?
• Where is sensation lost?

Answer 8

• Can be injected into multiple sites, eg: fat of sacral canal (that surrounds proximal parts of sacral nerves); via sacral hiatus; via posterior sacral foramina (into sacral canal around spinal nerve roots).
• Can alter amount injected and position of patient.
• Sensation is lost inferior to the epidural block.

Question 9

Injury of Coccyx:

• Aetiology?
• Why may treatment be needed?
• Is pain relief hard or easy to give?

Answer 9

• Falling on buttocks abruptly (can cause subperiosteal bruising, or a fracture of the coccyx, or a fracture-dislocation of sacrococcygeal joint). Can also occur from difficult childbirths.
• Displacement is common and surgical removal is needed to resolve consequences of this displacement.
• Coccygodynia (pain in coccyx) is hard to give.

Question 10

Sacralisation of L5 vertebra:

- What is it?

Answer 10

• L5 incorporation into the sacrum. Causes L5-S1 level to become strong whilst L4-L5 level degenerates (painful).

Question 11

Lumbarisation of S1 vertebra:

- What is it?

Answer 11

• S1 separates from sacrum and fuses with L5.

Question 12

Effects of aging on vertebrae:

• What happens to the bone density and strength?
• What happens to the articular surfaces + superior/inferior surfaces of vertebral body?
• What happens to the person’s height?
• Why do osteophytes develop?
• Name of stresses at vertebral bodies vs zygapophysical joints?

Answer 12

• Decreased bone density and strength (particularly in centre of vertebral body)
• Become concave
• Shortens with aging
• Shape changes causes an increased compressive force at the periphery of vertebral bodies. Osteophytes develop around vertebral body margins as well as at zygapophysical joints (develop along attachments of joint capsules & accessory ligaments - especially at superior articular facets). Whereas articular cartilage develops around articular facets of inferior process.
• Spondylosis vs osteoarthritis, respecitvely.

Question 13

What is spondylosis?

Answer 13

This is compression on spinal nerve roots/spinal cord as a result of degeneration of the spinal column from any cause. If on spinal nerve roots, it is radiculopathy. If on spinal cord, it is myelopathy.

Question 14

What is scoliosis?

Answer 14

This is abnormal lateral curvature of the vertebral column

Question 15

What is kyphosis?

Answer 15

Excessive curvature of the spine - convex posteriorly. Causes hunchback.

*Also used to describe normal spine shape in thoracic and sacral regions.

Question 16

What is Lordosis?

Answer 16

Excessive curvature of the spine - concave posteriorly.

*Also used to describe normal spine shape in cervical and lumbar regions.

Question 17

Spina Bifida Occulta:

• What is it?
• How does it appear?
• Consequences?

Answer 17

• Vertebral arch of L5 and/or S1 fails to develop normally and fuse posterior to the vertebral canal.
• Defect is concealed by overlying skin. Often indicated by a tuft of hair. Can detect in newborns by palpating adjacent vertebrae.
• Often no back problems.

Question 18

Spina Bifida Cystica:

• More or less severe than spina bifida occulta?
• Difference between meningocele and meningomyelocele?
• What can severe cases of meningomyelocele lead to?
• How can severe forms originate?

Answer 18

• More severe as 1 or more vertebral arches do not form completely.
• Meningocele = Herniation of meninges vs Meningomyelocele = Herniation of the spinal cord.
• Meningomyelocele can lead to neurological problems such as paralysis of limbs, bladder disturbances, loss of bowel control.
• Originate from neural tube defects (eg. defective closure of tube in 4th week of development).

Question 19

Effects of aging on IV discs:

• What happens to the nucleus pulposi?
• What happens to annulus fibrosus due to the increased weight load?
• What happens to the overall height of a patient?
• When does disc narrowing suggest pathology?

Answer 19

• It dehydrates, increases in collagen, loses elastin + proteoglycans. Also become stiffer + more resistant to deformation.
• Annulus fibrosus gets thicker lamellae and develop fissures + cavities.
• Shortens with age (cavities mean that you get overall shortening).
• Especially when the IV disc is narrower than the superior discs.

Question 20

Herniation of nucleus pulposus:

• Which is more likely to be damaged in young people - disc or vertebrae?
• Which part of the annulus fibrosus is thinnest?
• Which direction is the most likely for herniation? Why?
• What gives acute pain with herniation?
• What gives chronic pain with herniation?
• Which regions are most likely to have herniations?
• What can happen to intervertebral space as a result of herniation?
• Why would acute herniation in the elderly be suspicious?

Answer 20

• The intevertebral discs are so strong that it is most likely to damage the vertebrae instead. Violent hyperflexion may cause IV disc and adjacent vertebrae to break.
• The posterior section of the annulus fibrosus is thinnest.
• Herniations tend to go in the posterolateral direction as there is a lack of longitudinal ligaments here.
• Acute pain = Pressure on longitudinal ligaments and periphery of annulus fibrosus. Also due to local inflammation caused by chemical irritation by substances from nucleus pulposus.
• Chronic pain = Pressure on spinal nerve roots (also referred pain to that dermatome).
• Regions in the lumbar and lumbarsacral areas. This is because IV discs are largest and movements are consequently greater.
• Intervertebral spaces can decrease. Also, narrowing of intervertebral foramina may occur.
• Acute herniation in the elderly is suspicious as their nucleus pulposus tends to be drier, increasingly fibrosed, and granular - instead compression of the nerve roots is likely to be due to ossification of IV foramina.

Question 21

Sciatica:

• Which parts of sciatic nerve tend to be compressed?
• Common cause?
• Which movements can exacerbate pain?

Answer 21

• L5-S1 regions
• Due to narrowing of IV foramina (osteophytes can do this).
• Movements which stretch the sciatic nerve (eg. flex thigh with knee extended).

Question 22

Give the 4 stages of disc herniation

Answer 22

1. Disc Degeneration (chemical changes, associated with aging, causes disc to weaken without herniation).
2. Prolapse (protrusion of nucleus pulposus with slight impingement into spinal canal)
3. Extrusion (nucleus pulposus breaks through annulus fibrosus but stays in disc space)
4. Sequestration (nucleus pulposus breaks through annulus fibrosus and lies outside disc space in spinal canal.

Question 23

What is Steele’s Rule of Thirds?

Answer 23

With atlas ring:
1/3 = Dens
1/3 = Spinal Cord
1/3 = Fluid filled space + spinal surrounding tissue

*This is why some people aren’t injured/in pain (why some anterior displacement can be assymptomatic, until there is a large movement).

Question 24

Rupture of Alar Ligaments:

• Where are these?
• Stronger or weaker than transverse ligament?
• Which motion can rupture them?

Answer 24

• Between side of dens and lateral margin of foramen magnum
• Weaker than transverse ligament
• Flexion + rotation combined can tear 1 or both alar ligaments. If they rupture, you get 30% more movement on the contralateral side.

Question 25

Fractures + Dislocations of Vertebrae:

• What character of movements can cause fractures, dislocations or fracture-dislocations?
• What injury can sudden forceful flexion cause?
• Which ligament can be injured by forceful flexion + anterior displacement?
• Which injury can occur with forceful extension?
• Which ligament tends to stretch/rupture with whiplash?
• Which vertebrae of the non-cervical column are most prone to fractures? Why?
• Why are fractures unlikely in thoracic and lumbar regions?
• What is spondylolysis?

Answer 25

• Those which excessive + sudden + violent movements, or a movement not permitted in a region.
• Compression fracture of vertebral body of 1 or more vertebrae.
• Interspinous ligament can be injured by forceful flexion + anterior displacement.
• Compression of vertebral arches of 1 or more vertebrae
• The anterior longitudinal ligament can be stretched/torn in whiplash.
• T11/T12 as the mobility of thoracic + lumbar regions change abruptly.
• This is because of interlocking articular processes.
• This is where there is a fracture of the pars interarticularis.

Question 26

Denervation of lumbar zygapophysical joints:

• Why do we give this treatment?
• How can it be done?
• Where is it done?

Answer 26

• To relieve back pain
• Sectioning nerves near joint, or by using radiofrequency.
• Directed at articular branches of 2 adjacent posterior rami of spinal nerves (as each joint receives innervation from both the nerve exiting and the superjacent nerve.

Question 27

• Give the 5 categories of structures with innervation in the back.
• Which of these tend to give localised back pain?

Answer 27

• Fibroskeletal structures + Meninges (innervated by recurrent meningeal branches of spinal nerves), Synovial joints + muscles (Posterior rami), and nervous tissue.
• Localised back pain tends to be fibroskeletal, muscular, or joint pain.

Question 28

Excessive Thoracic Kyphosis:

• Where does erosion occur to cause this?
• What shape does the vertebrae become?
• What complication can excessive kyphosis lead to?

Answer 28

• Anterior portion of vertebral body
• Wedge shaped
• Reduction in dynamic pulmonary capacity

Question 29

Excessive Lumbar Lordosis:

• Which muscular tends to be weakend alongside this condition?
• What can cause this condition?

Answer 29

• Trunkal musculature tends to be weakened.

- Change in centre of gravity (eg. pregnant women may get temporary lordosis. Obesity can also cause this).

Question 30

Scoliosis:

• What is this?
• Which way do spinous processes and ribs move?
• How can hemivertebra cause structural scoliosis?
• What is kyphoscoliosis?
• Complication of kyphoscoliosis?
• What can cause functional scoliosis?
• What is habit scoliosis?

Answer 30

• Abnormal lateral curvature, accompanied by rotation of vertebrae.
• Spinous processes turn towards cavity of abnormal curvature, and when patient bends over the ribs move posteriorly on the side with increased convexity.
• Hemivertebra is incomplete formation of 1/2 of a side of vertebrae. This can lead to lateral curvature.
• This is when kyphosis accompanies scoliosis. Can be caused by weakening of paraspinal muscles (eg. in Duchenne Muscular Dystrophy).
• Kyphoscoliosis can lead to complications such as restricted lung expansion + pulmonary hypertension + spinal cord compression.
• Functional scoliosis is caused by a problem extrinsic to normal vertebral column. Eg. weakness in intrinsic back muscles, or a difference in length of lower limb (with a compensatory pelvic tilt). Does not persist after problem is resolved.
• This is caused by habitual standing or sitting in an improper position.

Question 31

Cervical Spondylosis:

- What is it?

Answer 31

• Degenerative osteoarthritis of IV joints in cervical spine. There is narrowing of IV foramina so you can get compression of spinal nerve roots (radiculopathy) or spinal cord (myelopathy).

Question 32

Senile Kyphosis:

- What happens in this?

Answer 32

• Secondary curvature is lost with age, and primary curvature is re-established as continuous. Cervical + Lumbar regions lose their lordosis.

Question 33

Scheuermann’s Disease:

• What is it?
• Which region tends to be affected?

Answer 33

• This is a pathological cause for kyphosis. It is due to uneven vertebral growth in childhood - posterior border is taller than anterior border so discs are wedge shaped.
• Tends to affect thoracic but lumbar may also be affected.

Question 34

Lumbar Puncture:

• Why do we do this?
• Where do we do this? Why?
• Name the structures the needle passes through, in order.

Answer 34

• To collect a sample of Cerebrospinal Fluid.
• Inject needle around L3/L4 or L4/L5 as this is after the conus medullaris (end of spinal cord) at L2. We will now only be inserting into cauda equina rather than spinal cord (less neurological effects). Sample from subarachnoid space.
• Skin, Subcutaneous tissue, supraspinous ligament, interspinous ligament, Ligamentum flavum, epidural fat + veins, Dura mater, Arachnoid mater, Subarachnoid space.