Clinical Anatomy of the Spine Flashcards
What are some features of the osteology of the spine?
33 vertebrae = 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused), 4 coccygeal (fused)
4 curves of the spine = help maintain posture
What are the atypical vertebrae of the spine?
C1 and C2 (axis and atlas) = allow head movement
C7 (vertebral prominence) = no formena transverse process
What kind of joint are the intervertebral discs?
Intervertebral fibrocartilaginous joints
What kind of joints are zygapophysial joints?
Facet joints (synovial joints)
What movements do the facet joints and intervertebral discs allow?
Flexion, extension and lateral flexion = cumulative effect
Why is there less flexion and extension in the thoracic spine?
Ribs cause constraint
Why is lumbar rotation less than thoracic rotation?
Due to more vertically orientated facet joints
Why does the cervical spine allow the greatest movement?
Due to more horizontal facet joints
What happens to intervertebral discs with aging?
Lose water content = overload of facet joints and second degree osteoarthritis
What makes the pain of osteoarthritis and spondylosis worse?
Worse with extension of spine = facet joint injections with fluoroscopy can help
How can osteoarthritis in one or two motion segments be treated?
Localised fusion
What are some changes that can occur in intervertebral discs?
Outer annulus fibrosis and inner gelatinous nucleus pulposus
Where does degeneration of the intervertebral discs most commonly occur?
l4/5 and L5/S1 = also most common sites of slipped disc
What occurs in acute disc prolapse?
Lifting heavy object causes annulus tear, rich innervation to outer annulus, pain on coughing, most settle by three months
What do 60% of asymptomatic people over >45 show on an MRI?
Bulging disc = 10% have disc extrusion, 5% have asymptomatic nerve root compression
Where do motor nerves originate?
Anteriorly = bodies in anterior grey horn, (sensory neurons originate dorsally)
Where does the spinal cord run through?
Spinal canal = formed by vertebral column
What is formed from the anterior and posterior roots?
Mixed spinal nerve = exits via intervertebral column
How are sensory and motor nerve roots arranged in the lumbar spine?
Run together with two pairs at each level (susceptible to compression)
Where does the spinal cord end?
L1
What are some features of cauda equina syndrome?
Junctional upper motor neuron = weakness, spasticity, increased tone, hyperreflexia
Lower motor neuron = weakness, flaccidity, loss of reflexes
Where does the exiting nerve root outside the thecal sac pass?
Under pedicle of corresponding vertebra
Where are the transversing nerve roots located?
Pair whilst remaining in the thecal sac positioned anteriorly (in the lateral recess) in preparation to penetrate
What nerve is commonly compressed in disc prolapse?
Transversing nerve root commonly
What is compressed in a far lateral disc prolapse?
Exiting nerve root
What does nerve root compression cause?
Radiculopathy resulting in pain down sensory distribution of nerve root (dermatome) = called sciatica when in lower leg
Also weakness in any muscle supplied (myotome) and reduced/absent reflexes
What nerve roots contribute to the sciatic nerve?
L4, L5 and S1
Also S2 and S3
What is sciatica?
Radiation of nerve pain along sensory distribution of sciatic nerve
What can spinal stenosis cause?
Compression of nerve roots = usually by osteophytes and hypertrophied ligaments in osteoarthritis
What is the pain of spinal stenosis like?
Radiculopathy or burning leg on walking = neurogenic claudication
Some cases benefit from surgical decompression
What are some features of myelopathy?
Spinal cord compression (e.g tumour, disc prolapse)
Upper motor neuron signs
What causes cauda equina syndrome?
Caused by pressure (usually prolapsed disc) on all lumbosacral nerve roots at level of lesion (including sacral nerve roots for bladder/bowel control)
What are some symptoms of cauda equina syndrome?
Bilateral lower motor neuron signs, bladder and bowel dysfunction, saddle anaesthesia and loss of anal tone
What are the erector spinae muscles?
Iliocostalis, longissimus thoracis, spinalis thoracis = source of sprains and strains
What do the ligaments of the spine contribute to?
Stability
What is a chance fracture?
Very unstable = fractured vertebral body with disruption to posterior ligaments with/without fracture of posterior elements
How can a chance fracture be treated?
Surgical stabilisation
What are the landmarks for lumbar puncture and spinal anaesthesia?
Posterior iliac crest (L4), PSIS (S2)
What are some bone and joint causes of back pain?
Bone = fracture, tumour, infection Joint = spondylosis, osteoarthritis, spinal stenosis
What are some muscular and disc causes of back pain?
Muscles and ligaments = sprains and strains
Disc = degenerative back pain, sciatica, cauda equina syndrome
What does mechanical back pain relate to?
Joints, ligaments, and muscles = no red flag features
What are some features of mechanical back pain?
Worse with activity, relieved by rest, tends to be long course relapsing and remitting
What are some risk factors for mechanical back pain?
Obesity, poor posture, poor lifting technique
How can mechanical back pain be treated?
Nothing can be done surgically = analgesia, physio, pain clinic, chiropractor
What are some surgical treatments for back pain and what are they good for?
Discectomy/decompression, good for sciatica/leg pain which doesn’t settle with 3 months conservative management
How are some negatives of doing an MRI of the spine?
False positives, middle aged (about age 45) asymptomatic patients will have signs so not specific, less specific in ageing patients
