Months after my shoulder surgery, I have pain in my triceps which my physical therapist says is being "referred" from my shoulder. How does that work?

Months after my shoulder surgery, I have pain in my triceps which my physical therapist says is being "referred" from my shoulder. How does that work?

— Will D., Grants Pass

Referred pain is felt in some part of the body other than the site of origin, says Dr. Dan Saviers, a specialist in physiatry, the branch of medicine that seeks to restore function to damaged parts of the body.

Saviers says one of the best-known examples of referred pain is associated with heart attack. People who are suffering a heart attack often describe excruciating pain in the left arm or the shoulder, but that's not where the problem is.

Referred pain occurs when a pain signal comes into the spinal cord, and nerves not directly affected are stimulated. Through a mechanism nobody quite understands, the brain gets confused. The heart attack patient feels pain in the arm instead of the heart. Somebody who had shoulder surgery feels pain in the arm.

"It's not an exact science," Saviers says.

Referred pain seems to occur because nerves from various parts of the body converge on their way to the spinal cord. The sensory nerves from the heart, for example, flow into the same part of the spine that gathers nerve impulses from the shoulder. When a pain signal comes in, say, from the heart or shoulder, it stimulates nerves farther down the arm or in the neck.

An "ice cream" headache is a less serious example of the same phenomenon. Too much cold stuff in the mouth aggravates nerves in the palate, and the pain is referred to the forehead (warming the palate often eases this pain).

The "phantom limb" pain that amputees suffer seems to be another example of the same phenomenon.

Saviers says the body's ability to feel pain away from the problem area complicates a physician's work in diagnosis. A pinched nerve in the neck, for example, may radiate pain down the arm.

"When somebody comes in with unexplained pain, one of the triggers could be something irritating the abdomen and it's felt in the shoulders," he says.

"It makes you have to keep your eyes open."

Saviers says some parts of the body are more likely to generate referred pain, and the shoulder joint is high on that list.

"Pain referring down from the shoulder is so common I'm surprised when somebody doesn't have it," he says.

The hip is less likely to cause problems, and there's relatively little referred pain associated with the ankles or knees.

"We see it more with shoulders and pinched nerves in necks and backs and mid-back injuries," he says.

The key to treating referred pain is to locate the source and eliminate the problem, a process that can be time consuming and frustrating for physicians and patients alike. Some people have pinched nerves in their neck that radiate down their arms or have pinched nerves in their backs that radiate to their legs, and they may experience more pain in their extremities than in the neck or the back where the pain originates.

"You've got to fix the underlying problem," he says.

Treating the pain without locating the underlying trigger won't produce satisfactory results in the long run, he says. "That's like treating the cough instead of the pneumonia."

Call Bill Kettler with your medical questions at 776-4492, or e-mail them to: bkettler@mailtribune.com or send them to: Mail Tribune, Ask Your Doctors, P.O. Box 1108, Medford OR 97501.