Vertebral Column & Spinal Cord Flashcards
At what vertebral level does the spinal cord terminate in adults and children?
L1/L2 in adults
L3 in children
What vertebral level is lumbar puncture performed?
L3-L4 or L4-L5
What’s the surface anatomy of the cauda equina and the meninges?
Cauda equina: termination of spinal cord (L1/L2) through spinal canal -> S2
Meninges: subarachnoid space extends from foramen magnum of skull -> S2
Describe the layers a needle goes through to obtain CSF sample and how this differs to epidural anaesthetic
Skin -> subcutaneous fat -> supraspinous ligament -> interspinous ligament -> ligamentum flavum -> epidural space -> dura mater -> subdural space -> pia mater -> subarachnoid space filled with CSF
Anaesthetic: level of needle insertion depends upon site required for anaesthesia; stop inserting the needle once you’ve lost feeling of resistance as this will have pierced ligamentum flavum
Explain the structure of an IV disc
Nucleus Propulsus (rubbery core) made of GAGs to attract H20 Annulosus Fibrosus fibrocartilage rings surround NP
Attach to bodies of adjacent vertebrae from below C2 downwards via Hyaline cartilage (secondary cartilaginous joint)
In which direction do IV discs commonly herniate?
Postero-laterally (has least support from posterior longitudinal ligament)
Compress spinal nerve emerging below the body passing inferiorly
What are the roles of the vertebral column?
Carry and protect spinal cord and nerves Provide support to thoracic rib cage Transfer weight from upper body to lower limbs for stability Shock absorbing Muscle attachment point
What are the different vertebral regions?
C1-C7 T1-T12 L1-L5 S1-S5 Coccyx
Explain the structure of a typical vertebra - what makes up the neural arch?
Neural arch = pedicle + transverse process + lamina + spinous process
Vertebral body and vertebral canal
Articular facets
How do the C1 and C2 vertebrae differ from others?
(C1-atlas) Carries weight of cranium so has no body
Joins to occipital condyle on skull to permit movement
C2 (axis) has odontoid process to attach to C1 - can be fractured and impinge spinal cord
What does the vertebral artery run through on the cervical vertebrae?
Foramen transversarium - may be compressed in foramen narrowing
How do thoracic vertebrae differ from cervical?
Increase in size
Contain articular facets for the ribs
How are lumbar vertebrae specialised?
Have a larger body for stability and weight transmission
Articulations are aligned to prevent rotation
How are the sacral vertebrae specialised?
5 vertebrae fused together to transmit weight to pelvic girdle (down through lower limbs)
What are the joints between articular facets of adjacent vertebrae?
Zygapophyseal joints (synovial plane)
What’re the mechanics of IV discs to limit movement between vertebral bodies?
Force applied to vertebral column increases pressure in NP
= increases tension in surrounding AF
What are the ligaments of the vertebral column?
Ligamentum niche can be palpated in midline posterior neck
Supraspinous ligament
Interspinous ligament
Ligamentum flavum
Anterior and Posterior longitudinal ligaments
What are the natural spinal curvatures?
Cervical and Lumbar lordosis (curves anteriorly)
Thoracic and Sacral kyphosis
To balance centre of gravity
What’s spondylolysis?
Fracture in articular facets without vertebral displacement (spotty dog collar sign)
What’s spondylolisthesis?
Lumbar vertebrae moves anteriorly (slips forwards)
What movements is the vertebral column capable of?
Flexion, extension, rotation, lateral flexion
What muscle group keeps you upright?
Erector spinae group
What can get trapped in the suboccipital triangle? Symptoms?
C2/C3 dorsal rami
Posterior headache/occipital neuralgia
Where do spinal nerves exit the vertebral levels?
C1-C7 exit above vertebra
C8 downwards exit below
Via intervertebral foramen
How is grey and white matter arranged in the spinal cord?
Grey matter (cell bodies) in the centre White matter (myelinated tracts) in the outside Dorsal = sensory Ventral = motor Lateral horn = autonomic T1-L2 and S2-S4 only
What types of neurone do spinal nerves contain (mixed)?
Somatic motor
Somatic sensory
Visceral sensory
Autonomic (sympathetic T1-L2, parasympathetic S2-S4)
What’s the cauda equina? Cauda equina syndrome?
Collection of lumbar and sacral spinal nerves (after termination of the spinal cord at L1)
Supplies lower limb, pelvic floor, urinary and anal sphincters
Syndrome = compression of these nerves (tumour, spondylolisthesis, disc herniation, canal stenosis)
Reduced ankle jerk S1-S2 reflex
What’re the surface markings for caudal anaesthesia?
Line joining left and right PSIS /S2 spinous process
Sacral hiatus located at inferior apex of equilateral triangle
