contraction
(kŏn-trak'shŏn 
)
[L. contractio, a drawing together]
A shortening or tightening, as of a muscle; a shrinking or a reduction in size.
SEE: Braxton Hicks contractions.
concentric muscle c.Contraction of a muscle in which the extended muscle is shortened. Pulling the body up by grasping a bar over the head is such a contraction.
eccentric muscle c.Lengthening of the muscle as it contracts against resistance. Lowering the body from a position in which the body was supported by the flexed arms, i.e., holding onto a bar above the head, is such a contraction.
hourglass c.An excessive, irregular contraction of an organ at its center.
SEE: ectasia.
idiomuscular c.Motion produced by degenerated muscles without nerve stimulus.
incoordinate uterine c.An abnormality of the first stage of labor in which uterine contractions are too weak or too ineffective to dilate the cervix.
interdigestive migrating c.sMigrating motor complex.
isometric c.A muscular contraction in which the muscle increases tension but does not change its length. SYN: static muscle contraction.
isotonic c.A muscular contraction in which the muscle maintains constant tension by changing its length during the action.
ABBR: PVC
Contraction of the cardiac ventricle before the normal time, caused by an electrical impulse to the ventricle arising from a site other than the sinoatrial node. The PVC may be a single event or may occur several times a minute or in pairs or strings. Three or more PVCs in a row constitute ventricular tachycardia.static muscle c.Isometric contraction.
tetanic c.1Continuous muscular contraction.2A sudden, strong, sustained uterine contraction that jeopardizes maternal and fetal status. It may occur during oxytocin induction or stimulation of labor and can cause profound fetal distress, premature placental separation, or uterine rupture.
tonic c.Spasmodic contraction of a muscle for an extended period.