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.
Abnormal Heartbeat in Dogs (Arrhythmia) Definition of Arrhythmias. Arrhythmias are disturbances in the normal rhythm of the heart, either in frequency (beats too fast or slow), amplitude (beats too strong or weak), regularity (beats without a definable rhythm), or most commonly in all three areas.