costophrenic sulcus

cos·to·phren·ic sul·cus

the recess between the ribs and the lateral-most portion of the diaphragm, partially occupied by the most caudal part of the lung; seen on radiographs as the costophrenic angle.
References in periodicals archive ?
A chest radiograph (Figure 1) showed pleural thickening in the region of the costophrenic sulcus, enlargement of the hilar and paratracheal lymph nodes, and a mass in the right upper lobe.