Spine Anatomy & Conditions Flashcards

1
Q

How many vertebrae are there and what is its distribution

A
  • 33 vertebrae - 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and 4 coccygeal
    • 24 are separable vertebrae - individual movement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Discuss the mobility of each vertebral type

A
  • Cervical and lumbar very mobile
    • Most problems and symptoms in the body - neck and lower back pain
  • Thoracic relatively immobile as ribs come out to limit movement
  • Sacrum and coccyx immobile as fused vertebrae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the properties of the vertebral body

A
  • 10% cortical bone and 90% cancellous bone - decrease weight and allow other functions within vertebra
  • Usually the main weight bearing part of the vertebra
  • Major site of contact between adjacent vertebrae
  • End plates - articular surfaces covered hyaline cartilage
  • Linked to adjacent vertebral bodies by intervertebral discs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the structure of the vertebrae

A
  • 1 spinous process
  • 2 transverse processes
  • 2 superior articular processes (facets) interlock with the vertebra above
  • 2 inferior articular processes (not shown) interlock with the vertebra below
  • Lamina joins the transverse process to spinous process
    • Laminectomy - removal of lamina and spinous process to increase foramen space
  • Pedicle connects transverse process to body
  • Lamina + pedicle = vertebral arch
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Explain the properties of the intervertebral disks

A
  • Mainly made of water, collagen and proteoglycans (hydrophilic properties to bind water)
  • Account for 25% of the length of the vertebral column
  • Lose height with age - lose water from disk causing loss of pressure
  • Slightly wedge shaped - secondary curvature of spine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Explain the 2 types of collagen in intervertebral disks

A
  • Annulus fibrosus - type 1 collagen forming lamellae of annular bands in varying orientation
    • Major shock absorber
    • Highly resilient under compression - stronger than vertebral body
    • Largest avascular structure - no blood supply, use diffusion for nutrients
  • Nucleus pulposus - type 2 collagen
    • Changes in size throughout day and changes with age
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

State the functions of the vertebral column

A
  • Protection - encloses and protects the spinal cord and cauda equina within the spinal canal
  • Support - carries the weight of the body above the pelvis
    • Vertebral bodies increase in size inferiorly as compression forces increase
    • Sacral vertebrae - fused, widened & concave anteriorly to transmit weight of the body through pelvis to legs
  • Axis - forms the central axis of the body
  • Movement - has roles in both posture and movement
  • Haemopoiesis - red marrow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the contents that pass through the vertebral foramen and intervertebral foramen

A
  • Vertebral foramen - spinal cord
  • Intervertebral foramen - roots of spinal nerves, blood vessels
    - Present only in cervical, lumbar and thoracic vertebrae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the characteristic features of lumbar vertebrae

A
  • Kidney shaped vertebral body
  • Vertebral arch posteriorly and vertebral body anteriorly
  • Vertebral foramen triangular
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the characterstic features of sacrum

A
  • Collection of 5 fused vertebrae
  • Upside down triangle
  • Contains facets for articulation with pelvis at sacro-iliac joints
  • Vertebral column continues along the core of the sacrum and ends at the fourth sacral vertebra as the sacral hiatus
  • Central canal contains the cauda equina
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the characteristic features of coccyx

A
  • Small bone which articulates with apex of sacrum
  • Collection of 4 fused vertebrae
  • Lack of vertebral arches so no vertebral canal (does not transmit spinal cord)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the major joint in the spinal column

A
  • Superior and inferior articular process connect to form facet joint
    • Synovial joints
    • Creates intervertebral foramen to create space for spinal nerve route
    • Prevent anterior displacement of vertebrae - helped by ligaments
    • Orientation of lumbar facet joints 45˚ - allows more flexion and extension but less rotation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

List the major ligaments in the vertebral column and describe their location

A
  • Anterior longitudinal ligament - anterior side of vertebral body
  • Posterior longitudinal ligament - posterior side of vertebral body
  • Ligamentum flavum - between lamina
  • Interspinous ligament - between vertebral arches
  • Supraspinous ligament - tips of spinous process
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Explain the function of anterior longitudinal ligament

A
  • Prevent hyperextension
  • Mobile over intervertebral disks
  • Stronger than posterior longitudinal ligament
  • Runs from the tubercle of C1 to the sacrum
    - Runs anterior to vertebral body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Explain the function of posterior longitudinal ligament

A
  • Prevents hyperflexion
  • Also runs throughout spinal cord
  • Runs from body of C2 to the sacral canal
    - Runs posterior to vertebral body
  • Dictate where disk prolapse occurs - rupture annulus occurs at lateral side of posterior longitudinal ligament
    • Where most stress is after tear
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Explain the function of ligamentum flavum

A
  • Yellow in colour - high elastin content
  • Between laminae of adjacent vertebrae
  • Limit hyperflexion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Explain the function of interspinous ligament

A
  • Relative weak sheets of fibrous tissue
  • Join one spinous process to another (attach between processes)
  • Increase stability of vertebral column by resisting excessive flexion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Explain the function of supraspinous ligament

A
  • Attach to tips of adjacent spinous process

- Restrict hyperflexion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Explain the patterns of normal curvature in the spine

A
  • Kyphosis - concave anteriorly
    • Thoracic and sacral curvatures are primary kyphotic curvatures that develop during fetal period
  • Lordosis - concave posteriorly
    - Cervical and lumbar curvature are secondary lordotic curvatures that develop during childhood in association with lifting the head and sitting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Explain abnormal curvature of the spine

A
  • In old age, secondary curvatures are lost
    • Disks begin to lose curvature - develop senile kyphosis
  • Pregnancy - exaggeration of lumbar lordosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

At what level does spinal cord end

A

L1-L2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe the anatomical approach when performing a lumbar puncture

A
  • Ligamentum flavum tells if needle is in epidural space
  • Skin is anesthetized
  • Palpate iliac crest - L3, L4, L5 processes
    • Do not insert too high as that is where spinal cord ends
  • Insert through skin, ligamentum flavum into dura until CSF drips out
    - Should be inserted 4-6 cm in adults
23
Q

Describe the clinical features of mechanical back pain

A
  • Pain in back when spine is loaded - standing or sitting (when gravity acts)
  • Worse with exercise, relieved with rest
  • Intermittent
  • Often triggered by innocuous activity
  • Predisposition overweight, unhealthy lifestyle, deconditioned core muscles
  • Tend to take 3 months to recover - physical and mental health factors
  • Benefits, fear to further spinal damage
24
Q

Describe the pathophysiology of mechanical back pain

A
  • Arise from disks, facet joints, ligaments
  • Disk loses height and pressure, inability to evenly transfer forces within disk spaces
    • Develop marginal osteophytes
    • Increased stress placed on facet joints - osteoarthritis
    • Decreased size of intervertebral foramen and compression of spinal nerves
25
Q

Explain the clinical features of prolapsed disk

A
  1. Disc degeneration - chemical changes causing discs to dehydrate and bulge
  2. Prolapse - protrusion of the nucleus pulposus with slight impingement into spinal cord
  3. Extrusion - nucleus pulposus breaks through the annulus fibrosis but still contained in disc space
  4. Sequestration - nucleus pulposus separates from the main body of the disc and enters the spinal canal
    - Nuclear material broken down by body
    - Most commonly occurs at L4/L5 or L5/S1
    - Usually herniates posteriolaterally, causing compression of spinal nerve routes
26
Q

Describe the different prolapsed disk types

A
  • Paracentral disk prolapse occurs 96% of the time - located within canal itself
    • Affects transverse nerve route
  • Far lateral disk prolapse occurs 2% of the time - occurs where nerve route exits
    • Affects exiting nerve route
  • Canal filling disk occurs 2% - compresses whole of cauda equina
27
Q

Describe sciatica and its effects

A
  • Compression of nerve roots which contribute to sciatic nerve
  • Compression of at least one of L4, L5, S1, S2, S3
  • Commonly occurs with disk prolapse - L4, L5, S1
    • S2 and S3 are fused together
  • Pain experienced is typically in the back and buttock and radiates to the dermatome supplied by the affected root
    • Paraesthesia (tingling feeling) is felt at the corresponding dermatomes
    • L4 sciatica gives pain on anterior thigh, anterior knee and medial shin
    • L5 sciatica gives pain on lateral thigh, lateral calf and dorsum of foot
    • S1 sciatica gives pain to posterior thigh, posterior calf, heel and sole of foot
28
Q

Describe cauda equina syndrome and its red flag symptoms

A
  • Compression of cauda equina due to big disk prolapse
    • Prolapse blocks entire canal
  • Red flag symptoms
    • Bilateral sciatica - compression of all nerve routes
    • Perianal numbness
    • Painless retention of urine - bladder cannot controllably empty
    • Urinary/ faecal incontinence - loss of anal sphincter sensory
    • Erectile dysfunction
  • Need to treat within 48 hours
29
Q

Describe the clinical features of lumbar canal stenosis

A
  • Narrowing of spinal canal
  • Seen in elderly patient
  • Occurs due to disk bulge, arthritis of facet joints (expands and encroaches into canal), ligamentum flavum hypertrophy
30
Q

Describe the pathophysiology of claudication

A
  • Neurogenic claudication - occurs in lumbar canal stenosis and causes pain and paraesthesia in legs when walking
    • Venous engorgement - veins fill up and begin to press on arterial supply due to smaller space from compression
    • Spinal nerves then become trapped, causing ischaemic nerve routes
  • Vascular claudication - problem in circulation of veins
  • Relieved with rest
31
Q

What is spondylolisthesis and its types

A
  • Slip forwards of vertebra above on the vertebra below
  • Dysplastic - abnormality in the shape of the facet joints
  • Isthmic - defects in the pars interarticularis
  • Degenerative - results from facet joint arthritis and joint remodelling
    • Presents with claudication
  • Traumatic - surgery, injury
  • Pathological - infection or malignancy
32
Q

Describe spondylolysis

A
  • Defect or stress fracture of pars interarticularis
    • Most common cause of isthmic spondylolisthesis
  • Pars interarticularis - area between inferior and superior articulate processes
  • Pars interarticularis could develop thinner and risk fracture in younger years
  • Most common at L5/S1
  • Present with back pain and L5 sciatica as arch not intact
33
Q

What is Filum terminale

A

Thin strand appearing inferior to conus medullaris

34
Q

What is conus medullaris

A

Lower end of spinal cord

35
Q

What is dura mater

A

Tough outermost membrane surrounding spinal cord

36
Q

What is cauda equina

A

Bundle of spinal nerves and spinal roots inferior to spinal cord

37
Q

What are common features of cervical vertebrae

A
  • Has transverse foramen in transverse process - carries vertebral arteries apart form C7
    • Enter cervical via C6
  • Bifid spinous process - apart from C7
  • Large triangular vertebral foramen
  • Has a superior and inferior articular facet
38
Q

Describe the characteristic features of the atlas

A
  • First cervical vertebrae
  • Bears weight of skill
  • Articulates with skull and C2
    • 50% of neck flexion and extension is from joint between atlas and skull
    • 50% of neck rotation is from joint between atlas and axis (C2)
  • No vertebral body
  • No spinous process
  • Injury at C1 less likely to cause neurological damage as more space - cord can drift
39
Q

Describe the characteristic features of axis

A
  • Second cervical vertebrae
  • Largest spinous process
  • Odontoid process (dens)
  • Dens and transverse ligament prevent horizontal displacement of atlas (prevent independent movement)
  • Transverse ligament damage - C1 and C2 can move independently of each other
    • Neurological injury - press against nerves
40
Q

Describe the characteristic features of vertebra prominens

A
  • 7th cervical vertebra
  • Often used as a location landmark - sticks out in neck flexion
  • Longest spinous process, not bifid
  • Does not transmit vertebral arteries as it comes in C6
  • Large transverse process but small foramen
    • Transmits accessory vertebral vein in transverse foramen
41
Q

What is the ligamentum nuchae

A
  • Extends from C2 to C7
  • Extra thickened area of supraspinous ligament
  • Provides attachments for muscles - e.g. Trapezius, rhomboids
  • Maintains secondary curvature of cervical spine
  • Helps cervical spine support skull
42
Q

Describe the characteristic features of the thoracic vertebrae

A
  • Demi-facets on sides of body for articulation with head of rib for T2 - T8
    • Whole facets for T9 - T10
  • Costal facets at transverse processes to articulate with neck of rib (except T11-T12)
  • Vertebral foramen small and circular
  • Articular processes face posterolaterally on superior rib and anteromedially on inferior rib
    • Permits lateral flexion and rotation but minimizes flexion or extension
43
Q

Explain the basic neuroanatomy of the posterior and anterior cords

A
  • Anterior cord - carries sensation and motor power
    • Light touch, pinprick and pain
  • Posterior cord (dorsal columns)
    • Vibration and proprioception (joint position + sense)
  • More central tracts move arms, more lateral tracts move legs
  • Anterior cord syndrome
    • Sensory and motor problems
  • Central cord syndrome - arm problems (inverted paraplegia)
  • Posterior cord syndrome - loss of coordination
44
Q

Define neural level

A
  • Last functional level before injury

- Eg. injury at T10 means nerves from above T10 should be working (neural level = T9)

45
Q

Where do nerve routes exit with respect to their corresponding body

A
  • C1 - C7 nerve routes exit above corresponding cervical vertebral body
    • C8 exists below C7 disk and above T1 disk
    • Further T1 and beyond exit below corresponding vertebral body
46
Q

Explain cervical spondylosis and its effects

A
  • Degenerative osteoarthritis of intervertebral joints in cervical spine
  • Age related changes - disk loses water, height and narrows
  • Pressure changes across disk - form osteophytes at front and back
  • Facet joints - joint begins to bear more weight and becomes arthritic
  • Develop cord and nerve route problems
    • Pressure on nerve routes leads to radiculopathy
      • Dermatomal sensory symptoms - paraesthesia, pain
      • Myotomal motor weakness
    • Pressure on cord leads to myelopathy
      • Global weakness, gait dysfunction, loss of balance, loss of bladder control
47
Q

Explain Hangman’s fracture

A
  • Unstable fracture of C2
  • Hyperextension of head on neck
  • Axis fractures through pars interarticularis (between superior and inferior facet)
  • Forward displacement of C1 and body of C2 from C3
48
Q

Explain peg fracture

A
  • Fracture of odontoid peg

- Blow to back of head - eg. Blow to back of head falling against a wall

49
Q

Explain Jefferson’s fracture

A
  • Fracture of anterior and posterior arches of atlas
  • Axial load - diving into shallow water
  • Typically causes pain but no neurological signs
  • Radially expand when fractures as skull pushes inward
  • May damage arteries at base of skull
50
Q

Explain whiplash injury

A
  • Common in low energy driving accidents
  • Hyperextension and then hyperflexion
    • Leads to tearing of cervical muscles and ligaments
  • Very poor correlation between the severity of injury and resulting symptoms
  • Arm pain, shoulder injury, lower back pain
51
Q

Explain effect of cervical prolapsed intervertebral disc

A
  • Tear annulus fibrosis, nucleus purposes migrates through into spinal canal
  • Wake up with pain
  • Will only have sensory and motor problems for the dermatome and myotome of the impinged nerve
52
Q

Explain the effects of cervical myelopathy

A
  • Compression of spinal cord
  • Elderly patients without develop osteophytes which intrude into canal
  • Thickening of ligamentum flavum
  • Signal change in spinal cord
  • Progressive disorder (chronic)
  • Will have an affect on nerves distributed below compression level
    • Eg. cervical myelopathy at C3/C4 may cause numbness in arms and legs
  • Classical presentation is loss of balance with poor coordination, decreased dexterity, weakness, numbness and sometimes paralysis
  • A myelopathy high in the spine can result in death - no intercostal muscles and diaphragm
    • C3 - C5 supplies phrenic nerve which innervates diaphragm
53
Q

Explain the effects of thoracic myelopathy

A
  • Commonly caused by tumour and fractures
  • Fracture of vertebra giving bony fragments
  • A compression high in the thoracic cord can stop innervation to intercostal muscles - body relies on diaphragm for breathing
  • Present with pain at the site of lesion, spastic paralysis of muscles in leg, paraesthesia in the dermatomes distal to the compression site and loss of sphincter control