bronchopulmonary segment four (right lung)
The lateral bronchopulmonary segment of the right middle lobe is supplied by the lateral segmental bronchus of the right middle lobar bronchus. Its main surface markings are laterally as a triangular suface that abuts the right fourth and fifth ribs.
It has a medial surface which neighbours the medial bronchopulmonary segment of the right middle lobe. Its superior surface forms part of the surface that lines the horizontal fissure with the anterior bronchopulmonary segment of the superior lobe directly above. Its inferior surface forms part of the oblique fissure; it is anterosuperior to the anterior basal bronchopulmonary segment of the inferior lobe.
Lymph nodes are particularly densely packed around the right middle lobar bronchus which distributes to this segment. Consequently, any cause of pronounced hilar lymphadenopathy can cause collapse of the segment and the middle lobe.
Last reviewed 01/2018