Costal Notches Of The Sternum, Anatomy

Description

Sternal costal notches line the right and left lateral borders of the manubrium and sternal body, forming shallow, cupped facets where the costal cartilages meet the breastbone in the anterior thoracic wall. Superiorly, the first costal notch sits at the manubrium near the clavicular notches, while the second costal notch straddles the manubriosternal junction at the sternal angle (angle of Louis), a palpable transverse ridge. Inferiorly, successive notches along the sternal body accommodate the third through sixth costal cartilages, and the seventh costal notch lies near the xiphisternal junction, where the xiphoid process begins. Bilateral symmetry is emphasized. Clinicians rely on these landmarks every day. The second costal cartilage at the sternal angle is the starting point for rib counting during chest examination and for orienting procedures such as thoracentesis, chest tube placement, and parasternal echocardiographic window localization, where an off by one interspace error has real consequences. Fine surface modeling around the manubriosternal and xiphisternal junctions also supports teaching of traumatic patterns, including sternal fractures and costochondral separations, and helps correlate focal parasternal tenderness seen in costochondritis (Tietze syndrome less commonly). Use this illustration in thoracic anatomy labs, osteology practicals, and clinical skills courses that emphasize surface anatomy of the chest, as well as in textbooks and patient education materials explaining rib levels, sternal landmarks, and anterior chest wall pain. It also suits cardiothoracic and emergency medicine publications discussing midline sternotomy approaches and complications such as sternal dehiscence in relation to parasternal costal cartilage attachments. Anatomical accuracy verified by SciePro's Medical Advisory Board.