Costodiaphragmatic Recess

recessus costodiaphragmaticus

The costodiaphragmatic recess is the most inferior and largest pleural recess, formed where the costal and diaphragmatic pleural reflections meet. It can accommodate approximately 200-300 mL of fluid before fluid becomes visible on upright chest X-ray. It extends from approximately the 8th rib anteriorly to the 12th rib posteriorly.

Region: Chest

Clinical Relevance

Clinical Notes

The costodiaphragmatic recess is the first location for pleural effusion accumulation, visible as blunting of the costophrenic angle on upright chest X-ray when 200-300 mL is present. Thoracentesis targets the recess at the 9th intercostal space in the midscapular line. Ultrasound-guided thoracentesis aims for the deepest point of the recess to avoid the diaphragm.

Pathology

Common Injuries & Conditions

Pleural Effusion in Costodiaphragmatic Recess

Fluid accumulation in the costodiaphragmatic recess blunting the costophrenic angle on chest X-ray, the earliest radiographic sign of pleural effusion, requiring thoracentesis when symptomatic or diagnostically necessary.