Why does one part of the body hurt when the origin of pain is somewhere else?
The best known example of this phenomenon—called "referred pain"—is the development of left arm or jaw pain as a result of coronary insufficiency (lack of blood flow through the heart vessels), or angina. The physiological explanation is that the brain cannot discern the true origin of the pain because of overlapping and intermingling nerve pathways that can converge in the spinal cord or in other locations. Here are some other important examples of referred pains:
Migraine, which originates in the brain, is often initially perceived as neck pain or a stiff neck because of descending neural circuits that go deep into the neck region.
Abdominal aortic aneurysm (ballooning of the aorta) is often perceived as back pain.
Esophagus pain can be felt in the back between the shoulder blades or even in the ear region.
Testicular pain is frequently perceived as abdominal pain because the testicles' nerve supply originates in the abdomen. The testes are located in the abdomen of the fetus and then descend into the groin.
Gas pain from intestines around the spleen in the left upper abdominal area is often referred to the left shoulder, neck, or chest.
Upper neck disturbances may be first perceived as pain in the forehead or within the eye.
Hip disease may be felt in the knee area.
Nasal or sinus pain may be perceived as a headache on the top of the head.
Chest disease may be felt as pain in the ear or face area.
The effective evaluation and treatment of most painful disorders requires time and diligence on the part of both the patient and the health professional.