Gross Anatomy of Mouse Heart and Principal Arteries and Veins

For the most part, there is going to be no need to separate the heart from the lungs. But, this was a pretty picture so we thought it would be cool to include it and of course, we always have something to say. If the heart is touching or is near touching the diaphragm at the time of the sternum removal, it is a good sign that the heart is enlarged. As the diaphragm is punctured, the pressure in the thoracic cavity is going to change causing the heart to retract, so it is a good observation to make at this early time. As with humans who don't get a great deal of exercise, are obese, or are getting old, the heart will be enlarged. Heart enlargement and heart lesions are typical in older animals. Also, don't be alarmed if the heart is still beating. Due to electric currents running through the body after death, some movement of the heart and other various muscles will continue to occur after euthanasia.