of the four bronchopulmonary segments typically comprising the superior lobe of the left lung, the most superior and posterior, supplied by the left apicoposterior segmental bronchus [B I + II]; they correspond approximately in position to the separate apical and posterior bronchopulmonary segments of the superior lobe of the right lung. SYN: segmentum (bronchopulmonale) apicoposterius [SI + II] [TA].