Diaphragm and Heart, Anterior View

Description

Centered in the lower thorax, the muscular diaphragm forms right and left domes with a broad central tendon, while the heart sits immediately superior to it within the fibrous pericardium. From an anterior perspective, the right ventricle occupies most of the sternocostal surface, the right atrium lies to the viewer’s left, and the left ventricle forms the left border and apex, which rests on the central tendon. Superiorly, the ascending aorta and pulmonary trunk emerge from the base, and coronary arteries course over the epicardial surface. Direct continuity between the fibrous pericardium and the diaphragm’s central tendon is a key relationship for understanding cardiophrenic mechanics and symptom patterns. Pericardial effusion and acute pericarditis can produce referred pain to the shoulder via the phrenic nerve (C3 to C5) because the phrenic nerve supplies both the fibrous pericardium and the central diaphragmatic pleura and peritoneum. Surgeons also respect this interface during a subxiphoid pericardial window, where the anterior pericardium is approached just superior to the central tendon and anterior diaphragm. Use this illustration in thoracic anatomy and cardiopulmonary blocks to teach surface anatomy of the cardiac chambers, the diaphragm’s domes, and why the heart’s apex is palpated in the left 5th intercostal space while functionally tethered inferiorly. It also fits operative anatomy references for pericardiocentesis and subxiphoid drainage, and for radiology teaching when correlating the cardiophrenic angles on chest radiographs. Anatomical accuracy verified by SciePro's Medical Advisory Board.