Sternal Angle, Anterior View

Description

Sternal angle (Angle of Louis) forms the palpable transverse ridge at the manubriosternal joint, where the manubrium meets the body of the sternum in the anterior midline of the thorax. From this fixed anterior perspective, the manubrium sits superiorly with its jugular notch and clavicular notches, while the sternal body extends inferiorly toward the xiphoid process. The sternal angle lies just inferior to the level of the sternoclavicular joints and aligns laterally with the attachments of the second costal cartilages, creating a dependable surface landmark on the breastbone. Clinically, the sternal angle anchors rib counting because the second costal cartilage is the first reliably identifiable rib anteriorly, letting you map intercostal spaces for auscultation, pleural procedures, chest drain placement, or needle decompression planning. It also approximates the transverse thoracic plane at the T4 to T5 intervertebral disc, a reference level used to teach the carina (tracheal bifurcation), the beginning and end of the aortic arch, and the boundary between superior and inferior mediastinum. Palpation of this ridge is also a common step in trauma and postoperative assessment when sternal tenderness or step-offs raise concern for manubriosternal dislocation or associated anterior chest wall injury. A hard landmark. The lighting and surface emphasis in this illustration make the manubriosternal junction readable without distracting soft tissue. Use this illustration in gross anatomy lab manuals, cardiothoracic surgery and anesthesiology teaching files, and clinical skills curricula that train rib-space localization for ECG lead placement, thoracentesis, and central venous access planning. It also fits well in radiology and physical exam chapters as a captioned bony landmark tied to mediastinal levels. Anatomical accuracy verified by SciePro's Medical Advisory Board.