Avascular necrosis (AVN), also called osteonecrosis, aseptic necrosis, or ischemic bone necrosis, is a condition that occurs when there is loss of blood to the bone. Because bone is living tissue that requires blood, an interruption to the blood supply causes bone to die. If not stopped, this process eventually causes the bone to collapse.
Avascular necrosis most commonly occurs in the upper leg. Other common sites are the upper arm, knees, shoulder, and ankles.
In addition to its ancient origins, there's modern-day evidence that it can help you stay healthy, especially when it comes to caring for your joints.
What Is Tai Chi?
"It almost looks like a slow-motion dance," says Mary L. Jurisson, MD, a physical medicine and rehabilitation specialist at the Mayo Clinic in Rochester, MN, who has taught tai chi.
When you do tai chi, you do a series of exercises that flow from one to another, with emphasis on proper posture. "When you watch people doing tai chi, you'll notice that they shift very smoothly and gracefully from one position to another," Jurisson says.
You can take tai chi classes in a group. You don't need a partner for most moves, though tai chi's "push hands practice" involves working in pairs.
There are many types of tai chi; the Yang style is the most popular. All include circular motions and concentration on breath patterns.
Beginners spend time committing specific moves to memory. Later, students learn to develop flow while improving balance and "energetic connection," says Gene Nelson, a certified master instructor and founder of Empire Tai Chi in Westchester, NY.
Tai chi uses big and small movements, often at the same time. "A single move might require you to step one way and turn your body another while moving your arms in different directions and softly transitioning between legs," Nelson says.
Tai Chi for Your Joints
While the calming, meditative nature of tai chi has long been well-known, it's only recently that the physical perks -- like moving with more ease -- have gained greater recognition. "Today, the vast majority of people in the U.S. who practice tai chi do it for health reasons, not just intellectual curiosity," Nelson says.
It's low-impact, so your knees, ankles, and other joints don't get overly stressed. "Almost everyone can do tai chi," Nelson says. In fact, a few of Nelson's students are in their 90s, and he says they often see results quickly.