Meaning of myasthenia gravis

my'asthe'nia gra'vis

Pronunciation: [key]
  1. a disease of impaired transmission of motor nerve impulses, characterized by episodic muscle weakness and easy fatigability, esp. of the face, tongue, neck, and respiratory muscles: caused by autoimmune destruction of acetylcholine receptors. Abbr.: MG
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.