tonic muscle


Also found in: Dictionary, Thesaurus, Encyclopedia.

tonic muscle

Skeletal muscle fibers that contract slowly and that cannot propagate an action potential along their cell membranes. Tonic muscles are uncommon in humans and are found only in the extraocular muscles, stapedius muscle, and intrafusal fibers of the muscle spindles. The remainder of human skeletal muscle contains only twitch fibers.
See also: muscle
References in periodicals archive ?
The proportion of the valves covered by tonic muscle differed among scallops (Table 3).
When the percentage of tonic adductor muscle in the overall adductor muscle was calculated from the impression on the right valve, Amusium balloti was shown to have very little tonic muscle compared with the other species (Fig.
The impressions of the tonic adductor muscle did not differ between the two valves in any species except Equichlamys bifrons in which the area of the tonic muscle was larger on the right than the left valve (Fig.
The sustained contraction of tonic muscle facilitates the determination of its force production.
This excess was consistently greater for the phasic muscle than for the tonic muscle, although the extent of overshoot varied among species.
Primary generalized tonic-clonic (PGTC) seizures are one of the most common and most severe forms of generalized seizures, accounting for approximately 60% of generalized epilepsy and approximately 20% of all epilepsy cases.(1) For the majority of patients, a PGTC seizure begins with a loss of consciousness without any prior warning symptoms and a sudden contraction of the tonic muscles, causing the patient to fall down (tonic phase).
Primary generalized tonic-clonic (PGTC) seizures are one of the most common and most severe forms of generalized seizures, accounting for approximately 60% of generalized epilepsy and approximately 20% of all epilepsy cases.(2) For the majority of patients, a PGTC seizure begins with a loss of consciousness without any prior warning symptoms and a sudden contraction of the tonic muscles, causing the patient to fall down (tonic phase).