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
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
Q
Explain the clinical features of prolapsed disk
A
- Disc degeneration - chemical changes causing discs to dehydrate and bulge
- Prolapse - protrusion of the nucleus pulposus with slight impingement into spinal cord
- Extrusion - nucleus pulposus breaks through the annulus fibrosis but still contained in disc space
- 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
- Pressure on nerve routes leads to radiculopathy
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
