esophageal achalasia disease

achalasia esophageal esophagus stomach sphincter vector anatomy hernia disease lower diagnosis acid medicine muscle larynx diaphragm closed reflux junction trachea throat medical gastrointestinal system digestion regurgitation illustration block problem narrowing les disorder difficult food liquid swallowing mouth nerve damaged paralyzed dilated squeeze collects swallow dysphagia stuck normal paraesophageal passage squeezed