Spine Anatomy & Conditions Flashcards
(53 cards)
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
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
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
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
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
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
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
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
9
Q
Describe the characteristic features of lumbar vertebrae
A
- Kidney shaped vertebral body
- Vertebral arch posteriorly and vertebral body anteriorly
- Vertebral foramen triangular
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
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)
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
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
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
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
16
Q
Explain the function of ligamentum flavum
A
- Yellow in colour - high elastin content
- Between laminae of adjacent vertebrae
- Limit hyperflexion
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
18
Q
Explain the function of supraspinous ligament
A
- Attach to tips of adjacent spinous process
- Restrict hyperflexion
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
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
21
Q
At what level does spinal cord end
A
L1-L2
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
Explain the clinical features of prolapsed disk
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
Describe the different prolapsed disk types
- 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
Describe sciatica and its effects
- 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
Describe cauda equina syndrome and its red flag symptoms
- 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
Describe the clinical features of lumbar canal stenosis
- 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
Describe the pathophysiology of claudication
- 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
What is spondylolisthesis and its types
- 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
Describe spondylolysis
- 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
What is Filum terminale
Thin strand appearing inferior to conus medullaris
34
What is conus medullaris
Lower end of spinal cord
35
What is dura mater
Tough outermost membrane surrounding spinal cord
36
What is cauda equina
Bundle of spinal nerves and spinal roots inferior to spinal cord
37
What are common features of cervical vertebrae
- 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
Describe the characteristic features of the atlas
- 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
Describe the characteristic features of axis
- 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
Describe the characteristic features of vertebra prominens
- 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
What is the ligamentum nuchae
- 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
Describe the characteristic features of the thoracic vertebrae
- 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
Explain the basic neuroanatomy of the posterior and anterior cords
- 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
Define neural level
- Last functional level before injury
| - Eg. injury at T10 means nerves from above T10 should be working (neural level = T9)
45
Where do nerve routes exit with respect to their corresponding body
- 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
Explain cervical spondylosis and its effects
- 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
Explain Hangman's fracture
- 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
Explain peg fracture
- Fracture of odontoid peg
| - Blow to back of head - eg. Blow to back of head falling against a wall
49
Explain Jefferson's fracture
- 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
Explain whiplash injury
- 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
Explain effect of cervical prolapsed intervertebral disc
- 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
Explain the effects of cervical myelopathy
- 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
Explain the effects of thoracic myelopathy
- 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
