What is a stress fracture?

DEAR DOCTOR K: What is a stress fracture?

DEAR READER: A patient of mine once asked me the same question, but with a twist: "In the emergency room they said I had a stress fracture. That's ridiculous, right? I mean, they're blaming stress for causing nearly every symptom these days. But how can stress cause a bone to break?" It's not emotional or mental "stress" that the word refers to in a stress fracture. It is stress -- unusual physical pressure -- placed on a bone that causes it to break. And the break typically does not separate the two ends of the bone. The X-ray, CT scan or MRI scan often shows no abnormality in the shape of the bone. Instead, there is a hairline crack inside the bone.

What’s the treatment for a subdural hematoma?

DEAR DOCTOR K: My mother is in her 70s. She fell a few weeks ago but seemed fine. Then she started to have double vision and some trouble with balance. A CT scan revealed a subdural hematoma. Her doctor advised only bed rest and medication. Does this seem reasonable to you?

DEAR READER: A subdural hematoma (or hemorrhage) occurs when blood vessels near the surface of the brain burst. Blood collects beneath the dura mater. That's the outermost layer of the brain's protective covering. Here is an illustration of a subdural hematoma:

What can I do to ease the pain from my broken ribs?

DEAR DOCTOR K: I recently broke a couple of ribs, and the pain is so bad I can hardly move. I can't sleep at night and I can't take a deep breath. I went to the doctor, but he said there isn't much he can do. I was surprised that he didn't even tape up my ribs. Is there anything I can do to help my ribs heal quicker and ease my discomfort?

DEAR READER: I understand why you ask the question. If you've ever fractured a bone, it has probably been put in a plaster cast or a splint. Keeping the broken parts of the bone from moving helps the bone heal and reduces the pain. The pain from a fracture generally occurs when the broken parts of the bone move. You know the old joke: "I'm OK, doc. It only hurts when I move."

How soon can I resume normal activities after an episode of low back pain?

DEAR DOCTOR K: I'm recovering from an episode of low back pain. How quickly (or slowly) should I resume my normal activities? I don't want to reinjure my back.

DEAR READER: You're right: It's a balancing act. Too rapid a return may precipitate a relapse, but too timid a return can delay -- or even prevent -- recovery. I can't give you a definitive answer because I don't know the details of your condition. But here's some general advice.

Are there exercises I can do to strengthen my weak ankles and prevent sprains?

DEAR DOCTOR K: I tend to sprain my ankle fairly often. Are there any exercises that could help me strengthen my ankles and prevent future sprains?

DEAR READER: Your ankles are remarkable joints. They must bear the full weight of your body, yet stay nimble and flexible. Every step, every jump, every move puts your ankles through a surprising range of motion. Even when you stand quietly, your ankles are constantly making minute adjustments to help you stay balanced.

What should I know about playground safety?

DEAR DOCTOR K: Two of my child's friends have hurt themselves playing on the playground recently. What can I do to keep my child safe?

DEAR READER: Kids get exercise, burn off energy and develop their motor skills by running, jumping and climbing on swing sets, monkey bars and other playground equipment. But each year more than 200,000 children in the United States visit emergency rooms for playground injuries. The most common are broken bones, bruises, scrapes and deeper cuts. More serious injuries also occur.

How long should I wait to fly after scuba diving?

DEAR DOCTOR K: I'm planning a diving vacation. A friend told me it's not safe to fly within 24 hours of diving. Why not?

DEAR READER: I'm not a diver myself, so I had to do some research to answer your question. The concern with flying soon after diving (or rising too quickly to the surface of the water after a deep dive) is something called decompression sickness. It's also known as "the bends."

What is an ankle sprain?

DEAR DOCTOR K: I recently sprained my ankle. I know I twisted it and that it hurts when I walk on it, but what exactly happened to my foot?

DEAR READER: Many people use the words "sprain" and "twist" interchangeably. Though you may sprain your ankle by twisting it, the words do not mean the same thing. A sprain is a tear of ligaments, which are the tough bands of fibrous tissue that connect bones to one another at a joint.