Infection of costal cartilage and the xiphoid is most likely caused by which mechanism?

• A. Extension Of Other Infections, Such As Wound Infection Or Subphrenic Abscess
• B. Direct Inoculation During Trauma
• C. Hematogenous Seeding
• D. Chronic Bronchitis

Answer: (A)

Infections of costal cartilage and the xiphoid usually arise from contiguous spread of an existing infection in nearby tissues. A wound infection or a subphrenic abscess can extend through the chest wall to involve the costochondral junctions and the sternum–xiphoid area. The cartilage itself is relatively avascular, which makes hematogenous seeding less likely and favors spread from an adjacent infected site rather than bloodstream infection. Direct inoculation during trauma is possible but less common as the primary route. Chronic bronchitis would not create a direct pathway to involve costal cartilage.