Diaphragm, Gross Anatomy

Description

Seen from a posterior perspective through partially transparent integument, the diaphragm forms a domed musculotendinous partition spanning the inferior thoracic aperture, with peripheral muscle fibers converging toward a central tendon that sits superior to the upper abdominal viscera. Costal attachments arise along the internal surfaces of the lower ribs and costal cartilages, while the crura anchor inferiorly to the anterolateral surfaces of the upper lumbar vertebral bodies and their intervertebral discs, flanking the midline. Medially, the right and left crura contribute to the margins of the esophageal hiatus, and the aortic hiatus lies posterior to the diaphragm at the level of the median arcuate ligament, closer to the vertebral column than the more anterior caval opening in the central tendon. Posterior orientation matters because it clarifies where the phrenic nerves reach the undersurface of the diaphragm and how the crural fibers relate to the esophagus and aorta. Surgeons use these relationships during hiatal hernia repair and fundoplication, where cruroplasty depends on recognizing the right crus as the dominant contributor to the esophageal hiatus and avoiding injury to the peritoneal reflections and adjacent sympathetic chains. Pain referral to the shoulder via the phrenic nerve (C3 to C5) makes more sense when you can trace the nerve’s course to the central tendon. Clean landmarks. Use this artwork for gross anatomy teaching on the thoracoabdominal boundary, respiratory mechanics, and posterior thoracic wall relationships, and for operative anatomy figures in texts covering antireflux surgery, diaphragmatic hernia, or transdiaphragmatic approaches. It also supports patient education materials explaining diaphragmatic function and postoperative diaphragmatic irritation. Anatomical accuracy verified by SciePro's Medical Advisory Board.