• Muscle body which has as its parts the myocardium proper and the conducting system of the heart.
  Foundational Model of Anatomy
  University of Washington, 2017
• Muscle tissue of the heart composed of striated, involuntary muscle known as cardiac muscle.
  CRISP Thesaurus
  National Institutes of Health, 2006
• The middle layer of heart tissue. The muscular myocardium is sandwiched between the outer layer (epicardium) and the inner layer (endocardium).
  Harvard Dictionary of Health Terms
  Harvard Medical Publishing, 2011
• The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2021
• The striated muscle tissue of the heart enveloped by the epicardium and the endocardium.
  NCI Thesaurus
  U.S. National Cancer Institute, 2021
• Cardiac muscle, in vertebrates, one of three major muscle types, found only in the heart. Cardiac muscle is similar to skeletal muscle, another major muscle type, in that it possesses contractile units known as sarcomeres; this feature, however, also distinguishes it from smooth muscle, the third...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2020