A muscle spasm, also known as a cramp, twitch or charley horse, is the sudden and involuntary forced contraction of a muscle. Experts weigh in on what's behind this sudden discomfort, when to be ...

In what's sometimes termed diffuse or distal esophageal spasm, there may also be a backflow of stomach acids or undigested foods. Known as regurgitation, this can lead to vomiting and heartburn ...

Hemifacial spasm (HFS) is a neurological disorder manifested by twitching on one side of the face due to involuntary contractions of the eyelid and other facial muscles. It usually begins gradually ...