Avascular necrosis is a medical condition that occurs when blood flow to a bone is disrupted, leading to the death of bone tissue. This lack of blood supply can result from various factors, including injury, long-term use of certain medications, or medical conditions like lupus or alcoholism. The most commonly affected areas are the hip and shoulder joints. As the bone tissue dies, it can cause pain, joint dysfunction, and eventually lead to the collapse of the bone structure. Early diagnosis and treatment are crucial to prevent further damage. Treatment options may include medications, physical therapy, or surgery, depending on the severity of the condition.