Rib 2 (left) — true rib

Function

A transitional rib — sharper than the first, longer, and humped by the serratus anterior's digitation. Its cartilage meets the sternum exactly at the angle of Louis, the rib-counting landmark.

Landmarks

• Tuberosity for the serratus anterior
• Scalene attachments

Articulations (joints)

• T1–T2 vertebrae (demifacets)
• Sternum via second costal cartilage at the sternal angle

Clinical relevance

Counting ribs from the sternal angle to the second rib keeps chest-tube placement and auscultation accurate.