myasthenia noun. [mʌɪǝs'Ɵi:nɪǝ] M19.
[from MYO- + ASTHENIA.]
Medicine. Abnormal muscular weakness; spec. = myasthenia gravis below.
myasthenia gravis ['grɑ:vɪs, 'gravɪs] [Latin = severe, grave] a rare chronic autoimmune disease, commoner in adolescents and young women, characterized by muscular weakness without atrophy and caused by a defect in the action of acetylcholine at neuromuscular junctions.

■ myasthenic [-'Ɵɛnɪk] adjective pertaining to, involving, or affected with myasthenia M19.

[TahlilGaran] English Dictionary ▲