Studies were carried out on 100 right lungs taken from human cadavers of both sexes aged from 1 month to 80 years. The material was divided into 3 age groups. The pulmonary artery and the bronchi were injected with 65% duracryl and then digested in sulfuric acid. The number and dimensions of the branches penetrating middle lobe were determined. In 57% of cases the lobe is supplied by 2 arteries and in 43% of cases by one artery. The length of arteries is up to 30 mm, and diameter 10.6 mm.