DEAR DR. DONOHUE: In his last football game, my son was hit hard. He didn’t lose consciousness, so I guess he didn’t have a concussion. He seemed a bit off it, and his coach wouldn’t let him play any more that day. What is the safe length of time to keep him from playing? The coach won’t let him in a game for a whole week. Are there guidelines for this? — N.D.

ANSWER: Your son’s coach has his players’ best interests at heart. Head injuries have short- and long-term consequences and should be dealt with according to the most conservative directions.

Let me clear up a misconception you have: Loss of consciousness isn’t a criterion for determining a concussion. Loss of consciousness elevates a head injury into a serious category, but a concussion is any head injury that produces even short-lived brain impairment. Confusion, temporary loss of memory, vacant staring, answering questions slowly and stumbling are a few of the signs that the brain has sustained a concussion.

Yes, there are guidelines for judging the seriousness of a head injury and the time required for recuperation. The Cantu guidelines are widely used. They categorize concussions into three grades. Grade 1 is any of the above signs I mentioned or the inability to retain new information. If these symptoms disappear in a half-hour, a player can resume playing in a week. A Grade 2 concussion is one where there is a brief loss of consciousness, less than one minute, or when the other symptoms listed above last longer than a half-hour but not longer than 24 hours. A player with a Grade 2 concussion ought not to play until two weeks have passed and unless all symptoms have been gone for a full week. A Grade 3 concussion is a longer loss of consciousness (more than a minute) or of concussion symptoms lasting for more than 24 hours. These players should not return to play for a full month.

DEAR DR. DONOHUE: I have a problem. My thumb really hurts, especially when I bowl. I have been bowling since my early 20s, and now I am in my mid-70s.

My hand doctor, who performed successful surgery for Dupuytren’s contracture, had multiple X-rays done, and the results were inconclusive. The report said negligible arthritis might be present. The doctor said it could be bowler’s thumb. Just what is that?

He recommended not using my thumb for a few months to see if it improves. Do you have any ideas? Are my bowling days over? — D.S.

ANSWER: A bowler’s thumb is pain at the base of the thumb, usually with a lump of hard tissue. The hard tissue is scar tissue. It encases a nerve to the thumb and exerts pressure on that nerve. Pain results.

Do exactly as your doctor says. Take a vacation from bowling. Then, when the pain goes, make some modifications in your bowling ball. The thumb hole should be enlarged and fitted to your thumb. The space between the thumb and the finger holes might have to be revised. You probably would benefit from using a lighter ball. Your bowling days aren’t over.

A hand doctor is a superspecialist in matters like this. If he made the diagnosis of bowler’s thumb, I believe him. Other conditions can cause similar pain.

DEAR DR. DONOHUE: I am a 75-year-old woman and an insulin-dependent diabetic. I would like information regarding fat deposits, mostly in my lower abdomen.

My waist size is 42 inches. When I was young, I was lean. I had four pregnancies, one of which was twins. That stretched my stomach muscles. Bodybuilders and others at the gym say there is no way to get rid of this. Do I have to live this way until I die? — J.N.

ANSWER: Abdominal exercises do not selectively remove fat from the abdomen. They do, however, tighten up abdominal muscles that then act like a girdle, holding abdominal organs in. Try this: Rest your lower legs on a chair while you lie on the floor. Raise your shoulders and upper back off the floor until your shoulder blades clear the floor. Hold that position for five or 10 seconds, and then lower yourself down. Repeat as many times as you can and as often as you can during the day.

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. Readers may also order health newsletters from www.rbmamall.com.