Overview A muscle strain is an injury to a muscle or a tendon — the fibrous tissue that connects muscles to bones. Minor injuries may only overstretch a muscle or tendon, while more severe injuries may involve partial or complete tears in these tissues. Sometimes called pulled muscles, strains commonly occur in the lower back and in the muscles at the back of the thigh (hamstrings).
Check with your doctor right away if you have dark urine, fever, muscle cramps or spasms, muscular pain, stiffness, tenderness, wasting or weakness, or unusual tiredness or weakness.
Muscular dystrophy is a group of diseases that causes muscles to become weaker and lose mass over time. The condition is caused by changes in the genes that make proteins needed to form healthy muscles. There are many types of muscular dystrophy. Symptoms of the most common type start in childhood, mostly in boys. Other types sometimes don't start until adulthood. Medicines and other ...
Overview Amyotrophic lateral sclerosis (a-my-o-TROE-fik LAT-ur-ul skluh-ROE-sis) is a nervous system disease that affects nerve cells in the brain and spinal cord. Also known as ALS, the disease leads to muscle weakness and gets worse over time. ALS often begins with muscle twitching and weakness in an arm or leg, trouble swallowing, or slurred speech. Eventually ALS affects the muscles needed ...
Myocarditis is inflammation of the heart muscle, called the myocardium. The condition can reduce the heart's ability to pump blood. Myocarditis can cause chest pain, shortness of breath, and rapid or irregular heartbeats. Infection with a virus is one cause of myocarditis. Sometimes myocarditis is caused by a medicine reaction or a condition that causes inflammation throughout the body.