Referred pain Flashcards
what is referred pain?
the perception of visceral pain some way away from the organ involved
what sort of nerve fibre is visceral pain transmitted along?
afferent autonomic nerves (visceral afferent)
where can autonomic afferent nerve fibres enter the CNS?
only where visceral efferent fibres leave it
somatic pain
pain arising from the skin
sensitive, well-localised, often sharp
many sensory receptors
visceral pain
fewer sensory endings in viscera often in SM pain poorly localised dull, heavy or gripping may be referred
what sensations are viscera insensitive to?
crushing, cutting, burning
what can cause pain in the viscera?
excessive stretching/contraction of their walls
what is a difference between visceral afferent and visceral efferent fibres?
visceral afferent fibres don’t have a peripheral synapse
visceral afferent fibres
join a spinal or cranial nerve and enter the CNS along a dorsal nerve root
cell body is found in the dorsal root ganglion
mechanism for referred pain?
nociceptors from several locations converge on a single ascending tract in the spinal cord
pain signals from the skin are more common
brain associates activation of the pathway with pain in the skin (brain confuses it with somatic part of pathway and thinks signals are coming from skin)
happens when nerve fibres from regions of high sensory input (such as skin) and nerve fibres from regions of normally low sensory input (such as internal organs) happen to converge on the same levels of the spinal cord
where might pain be felt from a myocardial infarction and why?
base of neck, jaw, shoulder and arm
pain signals from the heart enter the spinal cord at T1-4/5. When these regions are activated, brain thinks that the pain is coming from the skin there
where is pain from foregut structures felt?
epigastrium
where is pain from midgut structures felt?
umbilicus
where is pain from hindgut structures felt?
hypogastrium (sigmoid and rectum - S2-4)
where might pain from the appendix be felt?
right lower quadrant, umbilicus
where might pain from the bladder be felt?
lower abdomen and upper thighs
S2-4, T12-L2
where might pain from the diaphragm be felt?
shoulders
where might pain from the oesophagus be felt?
along sternum, left upper thorax
where might pain from the intestines be felt?
back (backache or sharp pain in the back), umbilicus
where might pain from the kidneys be felt?
posterior costovertebral angle, radiating forward around the flank
T10-L1
where might pain from the liver be felt?
right shoulder
where might pain from the pancreas be felt?
directly behind the pancreas, lower left quadrant, umbilicus
where might pain from the spleen be felt?
left shoulder and upper third of arm
where might pain from the ureter be felt?
costovertebral angle, radiating to the lower abdomen, testicles and inner thigh
L1/2
