In erect posture commonest site of foreign body in bronchus

(A) (Right posterior basal) (Pretest physical diagnosis)* The most common anatomic location for a foreign body in the right main stem bronchus or the right lower lobe.* The right main stem bronchus is wider, shorter and vertically placed, and therefore the posterior segment of the right upper lobe (If the patient aspirated while supine) are anatomically susceptible to aspiration pneumonia. The superior segment of the right lower lobe and left lower lobe (If the patient supine) are also susceptible to aspiration pneumonia. These three segments are often referred to on the aspiration segments of the long the basilar segments of both lungs are susceptible to aspiration if the patients aspirates while erect or sitting up.Aspiration in supine position* Right upper lobe - posterior segment* Right lower lobe - superior segment* Left lower lobe - superior segmentAspiration in sitting position* Right basilar segments of lower lobes **