MSK session 8-9 Flashcards
How many vertebrae are there?
33 vertebrae 7 cervical 12 thoracic 5 lumbar 5 sacral 4 coccygeal
Which vertebrae are mobile?
Cervical and lumbar
What are the functions of the vertebral column?
- central bony pillar of the body
- supports the skull, pelvis, upper limbs, thoracic cage
- protection of the spinal cord and the cauda equina
- movement-highly flexible structure of bones, intervertebral discs and ligaments
- haemopoiesis - red marrow
Why do vertebral bodies increase in size inferiorly?
Compression forces increase
What are the movements of the lumbar spine?
Flexion and extension
Lateral flexion
Rotation
What seven processes are there on the vertical arch of a typical lumbar vertebra?
1 spinous process
2 transverse processes
2 superior articular processes
2 inferior articular processes
What does the lamina in the vertebral arch connect?
Lamina connects transverse process to spinous process
What does the pedicle connect in a vertebral process?
Transverse process to vertebral body
What is a laminectomy?
Removal of the spinous process and lamina to increase space for nerves
What type of joints are facet joints?
Synovial joints
How do spinal nerves emerge from the vertebral column?
Intervertebral foramina
What determines the amount of flexion and rotation permitted at different levels in the vertebral column?
Orientation of the inferior and superior articular processes at the facet joints
Where are intervertebral discs fund?
Between vertebral bodies in the vertebral column
Where are the two regions found in intervertebral discs?
Nucleus pulposus (central) Annulus fibrosus (peripheral)
Why does the height of intervertebral discs decrease with age?
Intervertebral discs are made up of water, collagen and proteoglycans.
As age increases, less proteoglycans are produced and replacement is slower. The size of the proteoglycan chains decrease. Proteoglycans attract water so the amount of water present decreases. The discs lose their height.
Describe the structure and function of the annulus fibrosis of the intervertebral disc.
Structure:
Made from lamellae of annular bands. Each lamella has regular collagen fibres arranged in a different orientation.
Function:
In any particular movement the vertebral column is in, some of the lamellae are tended and some are relaxed, providing a constant pressure to the nucleus pulposus.
Are the intervertebral discs or the vertebral body more effective at resisting compression?
Intervertebral disc- fibrocartilage with a high water content to withstand pressure and act as a shock absorber
What is the nucleus pulposus?
Remnant of the notochord
Made up of type 2 collagen
Changes in size with age
Centrally located in an infant, more posterior in an adult
Why is the correct technique of manual handling important?
Intervertebral discs are very strong in axial compression
What are the major ligaments of the vertebral column?
Which is strongest?
Anterior longitudinal ligament (stronger)
Posterior longitudinal ligament
Describe the location and function of the anterior longitudinal ligament.
Anterior tubercle of atlas to sacrum. United with the periosteum of vertebral bodies
Prevents hyperextension
Describe the location and function of the posterior longitudinal ligament.
Body of axis to sacral canal
Prevents hyperflexion
What is ligamentum flavum?
Made up of elastic fibres
Between laminae of adjacent vertebrae
Stretched during flexion of the spine - limits hyperflexion
Where are interspinous and supraspinous ligaments found?
-Interspinous ligaments
Between borders of adjacent spinous processes
Well developed only in lumbar region
-supraspinous ligaments
Between tips of adjacent spinous processes
Tight in flexion
What does the sacrum articulate with?
L5 superiorly
Ilium laterally
Coccyx inferiorly
Describe the curvatures of the different regions of the vertebral column
Cervical - lordosis Thoracic - kyphosis Lumbar - lordosis Sacral - kyphosis Coccyx - kyphosis
Describe the curvature of the vertebral column in the foetus.
Primary curvature (retained throughout life in thoracic, sacral, coccygeal regions)
C-shaped
Kyphosis
When does the lumbar spine lose its primary kyphosis?
Crawling
Lumbar lordosis develops when the child begins to stand up and walk (secondary curvature)
Where does the centre of gravity pass through the vertebral column?
C1 and C2
C7 and T1
T12 and L1
L5 and S1
What happens do the structure of the vertebral column in old age?
Senile kyphosis
What happens to the vertebral column during pregnancy?
Exaggeration of lumbar lordosis
Suggest a suitable vertebral level at which the needle for a lumbar puncture should be inserted. Explain your reasoning.
L3/4 or L4/L5
After the conus medullaris so only mobile spinal nerve roots are here rather than the spinal cord as this is where there is the least chance of neurological damage
State the structures through which the needle will pass in order from the skin to the subarachanoid space in a lumbar puncture
Skin Subcutaneous tissue Supraspinous ligament Interspinous ligament Ligamentum flavum Epidural fat and veins Dura mater Arachnoid mater Subarachnoid space
What is mechanical back pain?
Pain when the spine is loaded (while standing or sitting due to gravity)
Worse with exercise and relieved by rest (when lying down)
What is marginal osteophytosis?
As age increases, load stresses on the intervertebral disc alter.
There is reactive marginal osteophytosis adjacent to affected endplates (senile ankylosis/spondylosis deformans)
What does disc degeneration and marginal osteophytes is lead to?
- Increases stress on facet joints —> osteoarthritis (innervated by meningeal branch of spinal nerve - pain
- Decreased size of intervertebral foramen and compression of spinal nerves
What is disc degeneration?
Chemical changes associated with ageing 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 purposes breaks through annulus fibrosis and separates from the main body of the disc in the spinal canal
What has happened when the symptoms of a slipped disc have resolved?
The disc material that had separated from the main body of the disc does not go back into the disc. The material is degenerated and this is an irreversible change to the vertebral disc.
What are the different types of disc prolapse?
Paracentral- within the vertebral canal
Far lateral - not in the vertebral canal, where the nerve root is exiting
Canal filling - compresses the entire cauda equina
What is sciatica?
Sciatica is compression of nerve roots which contribute to the sciatic nerve (L4 L5 S1 S2 S3)
NOT compression of the sciatic nerve
Loss of sensation over anterior thigh, anterior knee and medial shin due to a slipped disc. Which type of sciatica is this?
L4 sciatica
Loss of sensation over lateral thigh, lateral calf and dorsum of foot. Which type of sciatica is this?
L5 sciatica