The sternal angle (angle of Louis, manubriosternal junction) is the palpable transverse ridge on the anterior sternum at the junction of the manubrium and the sternal body, corresponding to the level of the T4-T5 intervertebral disc. It is one of the most clinically important surface landmarks, marking the level of the aortic arch, the bifurcation of the trachea (carina), the second costal cartilage and second rib, and the upper limit of the cardiac percussion area.
| Articulations |
|
|---|---|
| Landmarks |
|
| Ossification | Marks the manubriosternal joint, a symphysis between the manubrium and body of the sternum; it fuses in only about 10 percent of adults, usually late in life. |
The sternal angle is the universal starting point for rib counting in clinical examination: the second rib articulates with the sternum at this level, and ribs are counted downward from here. It is the surface marking for auscultating the aortic valve (second right intercostal space) and pulmonary valve (second left intercostal space). In median sternotomy, the sternal angle serves as a reference for ensuring symmetric skin incision. It is visible as a transverse ridge and palpable even in obese patients.
Find the jugular notch at the top of the sternum and slide your fingers about 5 cm straight down. You will feel a horizontal ridge where the manubrium meets the body of the sternum; this is the sternal angle. Move sideways onto the 2nd costal cartilage, which joins the sternum here, to start counting ribs.
Direct sternal trauma from steering wheel impact or CPR produces sternal fractures most commonly at the sternal angle, detectable as point tenderness and crepitus at the manubriosternal junction with posterior displacement on lateral chest radiograph, associated with myocardial contusion given the T4 cardiac level.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
