myo-, my-, myos-

(Greek: muscle; said to be from a Greek word meaning "mouse")

From Greek mu[s], my[os], meaning "mouse", as in myomancy.

amyoplasia (s) (noun), amyoplasias (pl)
Deficient formation of muscle tissue and a lack of muscle growth: As a result of significant malnutrition, Irvin had a form of acquired amyoplasia in his muscle tissues.
amyostasia (s) (noun) (no plural)
Difficulty in standing because of a tremor of the muscles or as a result of a lack of coordination: The elderly Mrs. Hathaway had to use a wheelchair to get around sometimes because of her amyostasia which prevented her to be on her feet and be upright.
amyotaxia, amyotaxy
Muscular incoordination attributable to cerebellar lesions; ataxia.
amyotonia (s) (noun), amyotonias (pl)
Generalized absence of muscle tone; a floppiness of the muscles: Amyotonias are usually associated with flabby muscles and an increased range of passive movements at the joints.
amyotrophia (s) (noun), amyotrophias (pl)
Lacking in muscle size and number of muscle fibers that takes place with aging, reduction in blood supply, or following physical inactivity, and malnutrition: The amyotrophia that anyone has is often a progressive deficiency of muscle tissue; especially, because that person doesn't move around and use his or her muscles.

There are numerous causes for the amyotrophias of muscles; including, chronic malnutrition, immobilizations, and denervation which is a loss of nerve supplies that may be caused by a disease; for example, in polio where the death of motor neurons causes the denervation of muscle fibers.

amyous (adjective), more amyous, most amyous
Lacking muscular tissue or without muscular strength: The amyous physical condition of many elderly people in nursing homes is believed to be a result of too much sitting around and not nearly enough physical exercise.
cardiomyopathy (s) (noun), cardiomyopathies (pl)
Any disease of the heart muscle; myocardiopathy: One chronic type of cardiomyopathy is connected to the overconsumption of alcoholic beverages, which is specifically termed as alcoholic heart muscle disease.
An acute viral disease characterized by inflammation and degeneration of skeletal and cardiac muscle and lesions of the central nervous system.
epimysial (adjective), more epimysial, most epimysial
Pertaining to the sheath of connective tissue that covers a muscle.