Tuesday morning, my anatomy tankmates and I continued our journey through the human body. The next stop brought us to the heart – arguably the most important muscle in the entire body (aside from trapezius) ;-).
The cadaver’s chest had already been cracked ahead of time, so we simply reflected the entire rib cage up towards the head to reveal the lungs and pericardial sac. After briefly examining the parietal and visceral pleura, phrenic nerve, and fibrous pericardial sac, we proceeded to extract the entire heart from our cadaver’s chest cavity.
One thing to note is the presence of a pace maker. From the first day we turned our cadaver face-up to dissect pectoralis major/minor, we knew she had a pace maker. Now we finally saw how it interacted with the heart. Spring-like wires (ultimately cut away to better examine the heart chambers) extended from the pace maker down into the mediastinum and traversed the heart internally from top to bottom. It was difficult to make out exactly where the wires were going, but my best guess is they had a close tie with the sinoatrial (SA) and atrioventricular (AV) nodes – the natural pacemakers of the heart.
To remove the heart, we had to cut away the major vasculature, namely the pulmonary vessels, the superior and inferior vena cava, and the aorta. We traced the network of coronary vessels which feed the heart, opened up the chambers and located the tricuspid and mitral (bicuspid) atrioventricular valves, examined chordae tendinae, papillary muscles, trabeculae carnae, etc.
Overall, the dissection of the heart was relatively simple. In fact, the only difficult part was removing some rock-hard chunks of coagulated blood to better visualize the structure of the vessels and chambers.
As I’ve learned since Tuesday, the heart’s embryology, electrophysiology, and other associated topics can be just a little more difficult than the actual dissection. 😉