心肌
Myocardium \My`o*car"di*um\, n. [NL., fr. Gr. ?, ?, muscle + ? heart.] (Anat.) The main substance of the muscular wall of the heart inclosed between the epicardium and endocardium.
myocardium n : the middle muscular layer of the heart wall [also: {myocardia} (pl)]