With the first ribs fixed by neck muscles (scalene muscles and sternocleidomastoid muscle), the intercostals muscles (especially external intercostal muscles and interchondral part of internal intercostal muscles of opposite side), elevate the 2nd to 12th ribs and thus act as inspiratory muscles.
Medical Dictionary. arrhythmia. play. noun arÂ·rhythÂ·mia \Ä-Ërith-mÄ-É\. Medical Definition of arrhythmia. : an alteration in rhythm of the heartbeat either in time or force.
Facts and definition of arrhythmias (heart rhythm disorders) 1  A heart rhythm disorder is an abnormal variation from the normal heartbeat. Heart rhythm disorders involve abnormalities of one or more of the following: heart rate, regularity of beats, sites where electrical impulses originate, or sequence of activation of heartbeats. Heart rhythm disorder is also referred to as an arrhythmia.