Ear, nose, and throat problems affect both children and adults. Knowing how to prevent them and how to treat them if they occur can help you stay healthy. See what you know about the ears, nose, and throat by taking this true-false quiz.

BMI, or body mass index, uses weight and height to calculate weight status for adults. BMI for children and teens also takes into account gender and age because healthy body fatness differs between boys and girls and changes as they grow. This BMI calculator will help you determine if your child is at a healthy weight.

This assessment is valid for women between the ages of 21 and 69 who have had sexual intercourse at least once and who have not had a hysterectomy with removal of the cervix.

Myasthenia gravis is a disease of the central nervous system characterized by sporadic muscular fatigue and weakness. It occurs chiefly in the muscles of swallowing and chewing, as well as the muscles of the eyes, face, and neck. This video explores possible causes of this disease, as well as available treatments.

Plastic surgery is becoming more popular, with the most common procedure now breast augmentation, or enlargement. Contrary to what you may think, women with breast implants aren't immune to breast cancer.

Information on more than 370 topics, featuring illustrations designed to clarify complex anatomy and procedures.

Tap into this interactive encyclopedia for instant access to information on more than 835 diseases and conditions.

Enjoy good health at every age: know your body and how it works, eat well and stay active, and follow a plan for disease prevention.