Demonstrating ReferredPain
You’ll need a small plastic bin (approximately 1 quart volume orlarge enough to place your elbow into it), water, and ice cubes toconduct this lab.
Referred pain is a sensory experience in whichpain is perceived as arising in one area of the body when in factanother, often quite remote area is receiving the painful stimulus.Thus the pain is said to be “referred†to a different area. Many ofus have experienced referred pain as a radiating pain in theforehead after quickly swallowing an ice-cold drink. Referred painis important in many types of clinical diagnosis because damage tomany visceral organs results in this phenomenon. For example,inadequate oxygenation of the heart muscle often results in painbeing referred to the chest wall and left shoulder (anginapectoris), and the reflux of gastric juice into the esophaguscauses a sensation of intense discomfort in the thorax referred toas heartburn.
The phenomenon of referred pain is easily demonstrated in thelaboratory. You’ll want to conduct the following experiment on acounter near a sink.
Fill the plastic container about one third full of water fromthe tap. Add about 15 ice cubes to the water in the bin. Allow theice water to sit for about 2-3 minutes before using.
Immerse your elbow in the ice water allowing your elbow to touchthe bottom of the plastic bin. Relax your hand and arm musclessomewhat. Note what you feel upon immersion in the water. Leaveyour elbow in the water for 1-2 minutes, depending on your comfortlevel (there will be some discomfort involved in this experiment).2 minutes is best. Has the “pain†that began in your elbowmoved?  After 2 minutes of immersion, remove your elbowfrom the ice water. Wait 3 more minutes and then make your lastrecording in the table.
Referred Pain: Record your results in thistable.
Time of observation | Your sensory experience (include localization of pain) |
on immersion | |
after 1-2 minutes | |
3 minutes after removal | |
Please answer the following questions:
1. The ulnar nerve, which serves the medial third of the hand,is involved in the phenomenon of referred pain experienced duringyour test. How does the localization of this referred paincorrespond to the areas served by the ulnar nerve?
2. Where would referred pain appear if the following organs werereceiving painful stimuli?
(see figure in Chapter 13 of your textbook for help).
Lungs and Diaphragm –
Appendix –
Heart –
