DEAR DR. DONOHUE: I am coming up on 84, and I have my teeth, eyes, hearing, lots of hair and a good brain. I hear of people waiting for body parts, and I would like to know how to contribute my body organs for someone in need. Whom do I contact, and what sort of legal papers do I give to my sons so that everything can be arranged upon my demise? – P.H.

ANSWER: If everyone had your altruism, there would not be more than 80,000 North Americans now on a waiting list for a donor organ. My hat is off to you.

The first thing to do is to notify all your relatives of your wishes and put it in writing. At your death, your next of kin will be asked what to do with your body, and unless you have made it clear to them, it is unlikely that they will think of organ donation.

In many states, people can affix to their driver’s license instructions that their organs are to be donated. Most states have donor registries for such donations. Contact your state health department about how to effect this. Or, call the local hospital to see if there is an organ procurement coordinator who can fill in the details for you.

If you’re stymied and cannot find the information, contact the Coalition on Donation by dialing 1-800-355-SHARE. The coalition’s Web site is www.donatelife.net. If you do not have a computer, the local library can often help you make the connection.

DEAR DR. DONOHUE: Please explain for me dropped foot. How does it happen, and how long does it take to heal? – J.R.

ANSWER: Every time people lift a foot off the ground to take a step, leg muscles hold the foot in place so it doesn’t flop downward. The muscles do that because nerves tell them that they’ve got to hold the foot up, or people will stumble.

When there is nerve damage, leg muscles don’t get the signal to keep the foot propped up when it comes off the ground. The foot “drops.”

The next question is, Why isn’t the nerve working? Diabetes can interfere with nerve function. So can a deficit of vitamin B-12. Some inherited conditions are responsible for foot drop. The list goes on, but quite often, a cause cannot be tracked down.

If there is a fixable cause for foot drop, dealing with it can sometimes reverse nerve damage and correct the foot drop. How long that takes is an unanswerable question.

If no cause can be found or if no treatable condition is discovered, then treatment consists of using devices like braces that keep the foot in place when it is lifted off the ground.

DEAR DR. DONOHUE: Could you please give me some insight on skin tags? I can’t find much information on them. What causes them? I have had them burned off, snipped off and acided off, but I feel silly going to a doctor for them. What can I do on my own? Are they related to diabetes? – S.S.

ANSWER: Two percent of adults have skin tags. Their cause is not known.

They are flesh-colored to brown, dangling, icicle-like skin appendages that average about four-tenths of an inch (1 cm) in length.

Unless they happen to be in a bothersome position or are irritated by jewelry or clothes, they can be left alone.

I can’t find any information that relates them to diabetes. From time to time, articles appear that suggest they might be markers of colon polyps. The relationship, however, is not so strong that people with them are advised to do anything but follow the usual recommendations for colon cancer screening.

They are easy to remove, but it’s probably not a wise idea to do so on your own. For one thing, you want to make sure that you are dealing with a skin tag and not something else. For another, self-treatment can stir up an infection.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475.