The QRS complex is a group of deflections in an electrocardiographic (ECG or EKG) tracing that represent the depolarization of the ventricles of the heart, which initiates contraction of the ventricles.
The quadriceps is one of the great extensor muscles of the legs, running from the front of the thigh to the knee. It acts to extend the leg and to flex the thigh.
The quadriceps femoris is a muscle of the thigh which acts to extend the leg and to flex the thigh.
A quail is a small, short-tailed chickenlike bird found in the wild.
Quarantine is the enforced isolation or restriction of free movement imposed to prevent the spread a contagious disease.
Quasi-steady means seemingly, but not actually, a steady state of movement.
Quiescent means to be still or inactive; dormant.
Quinidine is an antidysrhythmic agent used as a bisulfate, gluconate, polygalacturonate, or sulfate. It is prescribed in the treatment of atrial flutter, atrial fibrillation, premature ventricular contractions, and tachycardias.