5 - The Lumbar Spine and Associated Disorders

Question 1

How many of each of the 5 types of vertebrae are there?

Answer 1

• Cervical - 7
• Thoracic - 12
• Lumbar - 5
• Sacral - 5 (fused)
• Coccygeal - 4 (fused)

Question 2

What type of curvature is seen in the thoracic and sacral regions of the spine?

Answer 2

Primary kyphotic curvature (concave anteriorly)

Question 3

What type of curvature is seen in the cervical and lumbar regions of the spine?

Answer 3

Secondary lordotic curvatures (concave posteriorly)

Question 4

What are the functions of the vertebral column?

Answer 4

• Supports the weight of the body
• Protects the spinal cord and cauda equina
• Posture and locomotion
• Haematopoeisis in the bone marrow

Question 5

What type of joint is a facet joint between vertebrae? What type of cartilage lines the articular surfaces?

Answer 5

• Synovial joint
• Hyaline cartilage

Question 6

What movements can be performed by the cervical vertebrae?

Answer 6

• Flexion
• Extension
• Lateral flexion
• Rotation

Question 7

What movements can be performed by the thoracic vertebrae?

Answer 7

• Lateral flexion
• Rotation

Question 8

What movements can be performed by the lumbar vertebrae?

Answer 8

• Flexion
• Extension

Question 9

What are the two parts of an intervertebral disc and where are they found?

Answer 9

• Annulus fibrosus
• Nucleus pulposus

Question 10

What is significant about the annulus fibrosus in terms of its neurovascular supply?

Answer 10

It is both avascular and aneural

Question 11

The nucleus pulposus is a remnant of what embryonic structure?

Answer 11

The notochord

Question 12

When an intervertebral disc prolapses, what direction is it most likely to prolapse in?

Answer 12

• Posterior and paracentrically (lateral to the posterior longitudinal ligament)

Question 13

What is the name of the joints between the sacrum and the ilium of the pelvis?

Answer 13

Sacroiliac joints

Question 14

The central canal of the vertebral column ends at the level of ……. at the ……….. ………..

Answer 14

• S4
• Sacral hiatus

Question 15

Which nerve roots form the cauda equina?

Answer 15

L2 and below

Question 16

The 5 sacral vertebrae are incompletely fused. The sacral nerve fibres leave the central canal through the ………. ……… …………

Answer 16

Posterior sacral foramina

Question 17

There is a continuation of the pia mater of the conus medullaris of the spinal cord that attaches to the first segment of the coccyx. What is this called and what is it’s function?

Answer 17

• Filum terminale
• Gives longitudinal support to the spinal cord (holds it in place within the canal)

Question 18

In the foetus, the vertebral column is ……-shaped. This concavity is known as a ………….

Answer 18

• C-shaped
• Kyphosis

Question 19

In infancy, the cervical spine develops a posterior concavity. What is this called and what causes it’s development?

Answer 19

• Cervical lordosis
• Develops as the infant begins to lift its head and the intervertebral discs become more wedge-shaped

Question 20

In infancy, the lumbar spine develops a posterior concavity. What is this called and what causes it’s development?

Answer 20

• Lumbar lordosis
• Develops as an infant begins to stand up and walk, the intervertebral discs become more wedge-shaped

Question 21

What happens to the normal lumbar lordosis during pregnancy?

Answer 21

The additional abdominal mass leads to an exaggeration of the lumbar lordosis

Question 22

What affect does age have on the spinal curvature?

Answer 22

• The annulus fibrosus degenerates and the nucleus pulposus becomes dehydrated (disc atrophy)
• Some patients experience osteoporotic compression fractures
• Secondary curvatures start to disappear - senile kyphosis

Question 23

The centre of gravity of the body passes centrally through the curvatures of the spine. Which 4 sites of the spine does the centre of gravity pass through?

Answer 23

The top of the spine and boundaries between the types of vertebrae:

• C1/2
• C7/T1
• T12/L1
• L5/S1

Question 24

What condition is narrowing of the spinal canal?

Answer 24

Spinal stenosis

Question 25

How does mechanical back pain usually present?

Answer 25

* Pain when the spine is loaded, that worsens with exercise and is relieved by rest * Tends to be intermittent and triggered by day-to-day activities

Question 26

What are some risk factors of mechanical back pain?

Answer 26

* Obesity * Poor posture * Sedentary lifestyle (deoconditioning of paraspinal muscles) * Poorly-designed seating * Incorrect manual handling

Question 27

Describe the process of intervertebral disc degeneration with age.

Answer 27

* The **nucleus pulposus dehydrates** with age * Leads to **decreased disc height** and disc bulging * Osteophytes (bone spurs) develop next to the end plates of the discs - **marginal osteophytosis** * **Osteoarthritic changes** occur in the facet joints due to increased stress * Intervertebral foramina decrease in size, **compressing spinal nerves**

Question 28

What are the four stages of a disc herneation (slipped disc) and what occurs in each stage?

Answer 28

1. **Degeneration** - discs dehydrate and bulge with age 2. **Prolapse** - protrusion of the nucleus pulposus into the spinal canal, still contained under a thin rim of annulus fibrosus 3. **Extrusion** - nucleus pulposus breaks through annulus fibrosus but is still within the disc space 4. **Sequestration** - The nucleus pulposus separates from the body of the disc and enters the spinal canal

Question 29

Which sites are the most common for a slipped disc?

Question 30

Describe the most common type of intervertebral disc prolapse.

Answer 30

* Nucleus pulposus herniates posterolaterally (lateral to PLL) * **Paracentral prolapse**

Question 31

What are the two possible ways a spinal nerve root can be affected by a disc prolapse?

Answer 31

* **Effect on the exiting nerve root** - root emerging at the level of the disc (usually **far-lateral** herneations) * **Effect on the traversing nerve root** - root emerging at the level below the disc (**paracentral** herneations)

Question 32

What causes sciatica?

Answer 32

* Irritation or compression of one or more of the nerve roots that form the sciatic nerve (L4 - S3) * Often due to marginal osteophytosis, slipped disc etc.

Question 33

In sciatica, where is the pain experiecnced?

Answer 33

* Pain radiates from the back/buttock to the dermatome that is supplied by the affected nerve root * **L4** - anterior thigh, anterior knee, medial leg * **L5** - lateral thigh, lateral leg, dorsum of foot * **S1** - posterior thigh, posterior leg, heel, sole of foot

Question 34

In sciatica, where may paraesthesia be experiecnced?

Answer 34

* Experienced only in the nerve root's associated dermatome (not the full path from the lumbar spine to the skin)

Question 35

What are some common causes of cauda equina syndrome?

Answer 35

* Canal-filling disc prolapse * Tumours (of vertebrae or meninges) * Spinal infection/abscess * Spinal stenosis (due to arthritis) * Vertebral fracture * Spinal haemmorhage * Late-stage ankylosing spondylitis

Question 36

What are the red flag symptoms of cauda equina syndrome?

Answer 36

* Bilateral sciatica * Perianal numbness * Painless urine retention * Urinary/faecal incontinence * Erectile dysfunction

Question 37

How is cauda equina syndrome treated? What is the prognosis if this diagnosis is missed?

Answer 37

* Needs surgical decompression within 48 hours * Otherwise serious consequences: * Chronic pain * Impotence * Need intermittent self-catheterisation to pass urine * Faecal incontinence * Loss of sensation * Lower limb weakness requiring a wheelchair

Question 38

What is spinal canal stenosis?

Answer 38

Abnormal narrowing of the spinal canal that compresses the spinal cord or nerve roots

Question 39

What are the most common causes of spinal canal stenosis?

Answer 39

Most common causes: * Disc bulging * Facet joint osteoarthritis * Ligamentum flavum hypertrophy Other causes include: * Compression fractures of vertebrae * Spondylolisthesis * Trauma

Question 40

What are the symptoms of spinal canal stenosis?

Answer 40

* Discomfort when standing * Pain in the shoulder, arm or hand (cervical) or lower limb (lumbar) * Bilateral symptoms * Numbness below the level of stenosis * Weakness below the level of stenosis * Neurogenic claudication

Question 41

What is neurogenic claudication and what causes this to occur?

Answer 41

* Pain/paraesthesia on prolonged standing and walking, radiating like sciatica * Compression of spinal nerves as they emerge from the lumbosacral cord (stenosis) * Venous engorgement of the nerve roots during exercise leads to transient arterial ischaemia * Relieved by rest and flexion of the spine (as the canal is enlarged)

Question 42

What is spondylolisthesis?

Answer 42

Anterior displacement of the vertebrae above relative to the vertebrae below

Question 43

What are some of the common causes of spondylolisthesis?

Answer 43

* Congenital instability of facet joints * Defect in the pars interarticularis (i.e. stress fracture between the articular processes) * Trauma * Infection or malignancy * Caused by surgical intervention

Question 44

What is the difference between sponylolysis and spondylolisthesis?

Answer 44

* **Sponylolysis** - complete pars interarticularis fracture without displacement * **Spondylolisthesis** - anterior displacement of the vertebrae

Question 45

Describe how a lumbar puncture is performed?

Answer 45

* Patient lies on their side with back and hips flexed, spreads the spinous processes and stretches the ligamentum flavum * Needle is inserted between L3 and L4 (or L4 and L5) - found at the plane between the superior iliac crests * Needle must pass through the ligamentum flavum, dura and arachnoid and withdraw CSF from subarachnoid space