Spinal Pain Flashcards
What is pain?
An unpleasant sensory and emotional response to actual or perceived tissue damage
What is a nociceptor?
Free nerve endings within the tissues which react to nociception (potential tissue damage)
What are the three types of nociceptors?
Thermal: hot or cold
Mechanical: Pressure or stretch
Chemical: by products of inflammation e.g histamines or cytokines
What is the fast pain pathway?
Response to stimulation of mechanical or thermal nociceptors - signals travel down A delta fibres to cause intermittent sharp pain
What is the slow pain pathway?
Response by chemical nociceptors (inflammation) or mechanical nociceptors (swelling) - via C fibres causing a dull aching pain
What is the pathway of A delta fibres?
Enter the spinal cord via lamina I - synapse with a second order neurone - ascend in the spinothalamic tract to the PAG, thalamus and somatosensory cortex
What is the pathway of C fibres?
Enter spinal cord via lamina V - travel to lamina II and synapse with WDR - ascend the spinothalamic tract to the reticular formation and the somatosensory cortex (in the frontal and parietal lobes)
What is the difference in the two somatosensory cortecies?
The Parietal lobe - for pain intensity/location/quality
The Frontal lobe - for psychosocial interpretation of pain
How is pain modulated?
Descending neurones from the brainstem in the posterolateral funiculus - synapse in Lamina I and II - they cause inhibition via the opiod system to filter out the pain signals
What are the opioids in the descending inhibition pathway?
enkephalins and endorphins
What are the 6 sources of potential pain in the spine?
Outer 1/3rd of IC disc Facet joints Ligaments & muscles Dorsal root ganglion SIJ structures Referral from organs (e.g. prostrate)
What is somatic nociceptive pain?
Pain evoked by noxious stimulation of the structures WITHIN the spine - e.g. ligaments, muscles, discs
What are the symptoms of somatic nociceptive pain? (5)
Localised, ‘dull, ache’, intermittent, responds to painkillers, predictable pain on movement
What is somatic referred pain?
Noxious stimulation of structures in the spine causing referred pain AND local pain
Why is the pain referred in somatic referred pain?
Convergence of separate peripheral sensory neurones onto the same dorsal horn cell in the spinal cord
– the brain mistakes the pain from originating in the peripheral neurones – not the local spinal nerve
