RELATIONSHIPS BETWEEN DIVISIONS OF THE MIDDLE BRONCHUS AND VASCULARIZATION PATTERNS IN THE MIDDLE LUNG LOBE

In 100 right human lungs the main bronchus, the pulmonary artery and t he pulmonary vein were injected with 65% methyl methacrylate and then digested in sulphuric acid. The resulting specimens were studied to ob serve the divisions of the middle lobe bronchus and the types of arter ial and venous vascularization of this lobe. The lobe was always enter ed by one lobar bronchus, which usually divided into two segmental bro nchi. In 53% of the middle lobes with this bronchial pattern there was one artery. When the lobar bronchus divided into three branches, at l east two arteries entered the lobe in almost all cases. Complete consi stency between the pattern of bronchial division and that of arterial vascularization of the middle lobe was found in almost two-thirds of c ases. Associations between patterns of bronchial division and of venou s drainage from the middle lobe were found in slightly more than half of the cases.