LES Full Form in Medical is lower esophageal sphincter. The junction of the oesophagus and stomach is protected by a muscular ring called lower esophageal sphincter. Only by swallowing does the LES relax and allow food to travel down the oesophagus and into the stomach.
By staying closed, the LES stops acid from the stomach from leaking back up into the oesophagus (reflux). Heartburn occurs when stomach acid flows backward into the oesophagus because the lower esophageal sphincter (LES) does not seal completely. Many cases of GERD can be traced back to a weakened lower esophageal sphincter.
It is related to GERD which is characterized by the regurgitation of stomach contents into the oesophagus (food pipe). Your oesophagus is the tube that carries food from your mouth to your stomach. Symptoms of GERD include heartburn and other digestive distress.
The oesophagus connects the throat to your stomach and is used to transport food during digestion. The lower oesophagus has a ring containing muscle fibers that keeps food from coming back up after it has been swallowed. The LES is the collective name for these muscles.
LES: Lambert-Eaton Myasthenic Syndrome