Flashcards in MSK - Lumbar Spine Structure Deck (62):
How many vertebrae are there, and what groups are they divided into?
There are 33, and they are divided into cervical (7), thoracic (12), lumbar (5), sacral (5) and coccygeal (4)
How many of the vertebrae are discrete and capable of individual movement?
What are the functions of the vertebral column?
- Provides central bony pillar of the body, supporting skull, pelvis, upper limbs and thoracic cage
- protects spinal cord and cauda equina (acts as a conduit which cord can pass through, while still allowing nerve roots to leave)
- allows movement
- haemopoiesis takes place in the red marrow
Why do vertebral bodies increase in size inferiorly?
Due to increase in compression forces
What are the three movements of the lumbar spine?
- lateral flexion
What are the seven 'processes' found on the vertebral arch?
- 1 spinous process
- 2 transverse processes
- 2 superior articular processes
- 2 inferior articular processes
True or false - the vertebral body is made entirely of cortical bone?
False - it's 10% cortical bone, 90% cancellous bone
What are the articular surfaces of the vertebral body covered with?
What is the gap created by the vertebral arch called?
What connects the transverse process to the spinous process?
What connects the transverse process to the body?
What sort of joint is found at the articulation of the superior and inferior articular processes?
Synovial (facet) joint
What is the function of the 'facet' joints of the articular processes?
- prevents anterior displacement of vertebrae
- orientation determines amount of flexion and rotation permitted (moves easily in flexion, less easily in rotation)
What are the intervertebral discs composed of?
70% water, 20% collagen, 10% proteoglycans
How much of the length of the vertebral column is made up of intervertebral discs?
What are the two regions of the intervertebral disc?
Nucleus pulposus and annulus fibrosus
What is the annulus fibrosus composed of?
Lamellae of annular bands in varying orientations. The outer lamellae are type 1 collagen, and the inner lamellae are fibro-cartilaginous. Avascular and anneural
What is the function of the annulus fibrosus?
Surrounds nucleus pulposus and acts as a shock absorber. It is highly resilient under compression
What is the nucleus pulposus derived from embryologically?
What is the nucleus pulposus composed of?
Gelatinous, type 2 collagen with a high water content and high osmotic pressure.
True or false - the size of the nucleus pulposus is constant?
False - it changes in size throughout the day, and with age.
What are the five ligaments/ligament groups in the vertebral column?
- anterior longitudinal ligament
- posterior longitudinal ligament
- ligamentum flavum
- suprasponous ligament
- interspinous ligament
Where is the anterior longitudinal ligament found?
- Anterior tubercle of atlas to sacrum
- united with periosteum of vertebral bodies
- mobile over intervertebral discs
Where is the posterior longitudinal ligament found?
- body of axis to sacral canal
- continues superior to axis as 'tectorial membrane'
How are the functions of the anterior longitudinal ligament and the posterior longitudinal ligament different?
Anterior LL - prevents hyperextension
Posterior LL - prevents hyperflexion
What is the ligamentum flavum?
Ligament which is found between laminae of adjacent vertebrae. Yellow in colour due to elastic fibres. Stretched during flexion of the spine
What are the interspinous ligaments?
Relatively weak sheets of fibrous connective tissue which unite spinous processes along adjacent borders. Only well developed in the lumbar region. Fuses with supraspinous ligaments
What are the supraspinous ligaments?
Strong bands of white fibrous tissue which connect the tips of adjacent spinous processes. They are tight in flexion and lax in extension.
What does the sacrum articulate with?
L5 superiorly, ilium laterally and coccyx inferiorly
Which has more vertebrae, the sacrum or the coccyx?
Sacrum has 5 fused vertebrae, coccyx has 4
What is the name given to a curve posteriorly in the spine?
What is the name given to a curve anteriorly of the spine?
What is the primary curvature of a foetus?
Single C-shaped kyphosis of vertebral column in the foetus
What are the two kyphoses of the vertebral column?
Thooracic and sacrococcygeal
What are the 2 lordoses of the vertebral column?
Cervical and lumbar
How do the secondary curvatures develop in the child's spine?
- cervical lordosis develops when young child lifts head
- lumbar spine loses primary kyphosis during crawling
- lumbar lordosis develops when child begins to walk
At which points in the vertebral column does the centre of gravity pass through it?
- C1 and C2
- C7 and T1
- T12 and L1
- L5 and S1
These are the 'weak points' of the vertebral column
What is 'senile kyphosis'?
This occurs when the secondary curvatures of the spine start to disappear and a continuous primary curvature is re-established
What physiological change occurs to the spine during pregnancy?
Exaggeration of the lumbar lordosis
Why are lumbar punctures always performed after the conus medullaris?
Only mobile spinal nerve roots present, not the cord - least chance of neurological damage
What is mechanical back pain?
Pain which occurs when the spine is loaded - worse with exercise, relieved by rest
What factors predispose someone to mechanical back pain?
Overweight, unhealthy lifestyle, deconditioned core muscles
What is disc degeneration and marginal osteophytosis?
- the nucleus pulposus can dehydrate with age, so the height of the IV disc decreases
- load stresses on the IV disc alter, leading to reactive marginal osteophytosis adjacent to end plates
- increased stress placed on facet joints, leading to osteoarthritis
- decreased size of IV foramen leads to compression of spinal nerves
What is disc degeneration?
Chemical changes associated with aging cause discs to dehydrate and bulge
What is disc prolapse?
Protrusion of the nucleus pulposus with slight impingement into the spinal canal
What is disc extrusion?
Nucleus pulposus breaks through annulus fibrosus but remains within the disc space
What is disc sequestration?
Nucleus pulposus breaks through annulus fibrosus and separates from the main body of the disc in the spinal canal
Whee does 'slipped disc' most often occur?
L4/5 or L5/S1
How does slipped disc most commonly occur?
Herniates posterolaterally, causing compression of spinal nerve roots
What are the three types of disc prolapse?
- paracentral (96%)
- far lateral (2%)
- canal filling (2%)
What is sciatica?
Compression of the nerve roots which contribute to the sciatic nerve
Which nerve roots contribute to the sciatic nerve?
L4, L5, S1, S2, S3
Where is L4 sciatica felt?
Anterior thigh, anterior knee, medial shin
Where is L5 sciatica felt?
Lateral thigh, lateral calf, dorsum of foot
Where is S1 sciatica felt?
Posterior thigh, posterior calf, heel, sole of foot
Which age group of patients are most at risk of prolapsed intervertebral disc?
30 to 50 year olds
What is cauda equina syndrome?
Disc fills canal and compresses lumbar and sacral nerve
What are the symptoms of cauda equina syndrome?
- bilateral sciatica
- perianal numbness
- painless retention of urine
- urinary/faecal incontinence
- sexual dysfunction
What is lumbar canal stenosis?
Narrowing of the spinal canal, leading to compression of the spinal cord and nerves.
What is claudication?
Pain in the legs when walking
What is spondylolisthesis?
A slip forwards of one vertebra onto the vertebra below