Anatomy of the lungs

Anatomy of the lungs

The left lung is divided by the oblique fissure, which lies nearer to the vertical than horizontal, so the upper and lower lobes could also be called anterior and posterior. On the right, the equivalent of the left upper lobe is further divided to give the middle lobe. Each lobe is composed of segments, with anatom ically defined and named bronchial, pulmonary arterial and venous connections ( Figure 60.1 ). The right main bronchus (RMB) is shorter, wider and nearly vertical compared with the left main bronchus (LMB). As a consequence, inhaled foreign bodies are mor e likely to enter the RMB than the left ( Figure 60.2 ). The trachea and bronc hi have a systemic arterial blood supply delivered by the bronchial arteries, which arise directly from the nearby tho racic aorta. Lymphatic drainage tends to follow the bronchi. Lymph nodes are both named and identified by numbered ‘stations’ and more recently into zones, which are of importance in stag ing of lung cancer ( Figure 60.3 ). -

The assessment of patients requiring lung surgery • Surgical oncology as applied to chest surgery • Chest wall disorders • Posterio r A nterior Right upper lobe Posterior Apical Anterior Right lower lobe Horizontal /f_i ssu re Apical Middle lobe Medial Posterior Basal Lateral Lateral Oblique /f_i ssure Anterior Posterio r A nterior Left upper lobe Oblique /f_i ssure Posterior Apical Left lower lobe Anterior Apical Superior lingular Anterior Basa l Inferior lingular Lateral Posterior Figure 60.1 The lobar and segmental divisions of the lungs, right lung above and left lung below as if viewed from the side.