Fig. 4
Comparison of needle-induced pressure in the external intercostal muscles and PVS with and without pleural effusion. The needle exerts pressure on both the external intercostal muscles and the paravertebral space. The external intercostal muscles (EIM), paravertebral space (PVS), and the presence or absence of pleural effusion are considered in this context. *indicates statistically significant differences in external intercostal muscle pressure compared to PVS pressure. # indicates the statistical significance of the comparison between the two groups