Manubrium of sternum

Function

The handle-shaped top of the breastbone. It anchors the clavicles at the only joints linking the arms to the trunk skeleton, and its junction with the sternal body — the angle of Louis — marks the second rib for counting.

Landmarks

• Jugular (suprasternal) notch
• Clavicular notches
• Sternal angle (angle of Louis)
• First costal notch

Articulations (joints)

• Clavicles (sternoclavicular joints)
• First costal cartilages
• Body of the sternum (manubriosternal joint)

Clinical relevance

The sternal angle lies at the T4–5 disc level where the aortic arch begins and ends — a key landmark for chest imaging and for counting ribs.