An Anterior Perspective of the Transversus Thoracis Under the Skin of a Human Male

Description

Anteriorly, the sternum and costal cartilages frame the medial thoracic cage while the ribs sweep laterally toward the axillae, with portions of the proximal humeri and glenohumeral joints bracketing the upper trunk. Deep to the anterior chest wall, the transversus thoracis is arranged as multiple slips arising from the posterior surface of the inferior sternum and xiphoid process, then coursing superolaterally to insert on the internal surfaces of the costal cartilages, classically ribs 2 through 6. Intercostal musculature occupies the spaces between adjacent ribs laterally, reinforcing how this plane relates to the mechanics of the thoracic wall. Skin remains in place in concept, but the dissection depth is oriented to emphasize the inner anterior thorax rather than superficial pectoral layers. Clear anatomy. This anterior perspective matters because transversus thoracis defines a surgical and procedural neighborhood: the internal thoracic (internal mammary) artery and veins descend just lateral to the sternum on the deep surface of the anterior thoracic wall, and the muscle can partially obscure these vessels during exposure or harvesting for coronary artery bypass grafting. Its slips also intersect the course of anterior intercostal branches and sit close to the parasternal region where chest tube placement and parasternal blocks are planned, making the relationship between sternum, costal cartilages, and intercostal spaces more than academic. Small muscle, frequent landmark. Use this artwork for gross anatomy teaching on thoracic wall layers, for cardiothoracic surgery and CABG educational materials discussing internal thoracic vessel harvest, and for anesthesia content illustrating parasternal regional techniques and anterior intercostal anatomy. Anatomical accuracy verified by SciePro's Medical Advisory Board.