THE LARYNX, BRONCHI AND OESOPHAGUS
11 cm long. The lumen varies from 15 to 22 mm. The surface landmark of the
bifurcation is at the angle of Louis.
The right main bronchus makes an angle of some 25° with the vertical and is
therefore almost a direct continuation of the trachea. Since it is in this
alignment and since the lumen is larger than that of the left main bronchus,
foreign bodies are most liable to enter it. The right main bronchus gives
branches to the upper lobe (apical, posterior and anterior); the middle lobe
Fig. 105. Brooch op ulmpnary segments. 1,
Apical; 2, Apicoposterior; 3, Anterior; 4,
Lateral; 5, Medial; 6 Posterior; 7, Superior;
8, Anterior basal; 9, Lateral basal; 10, Medial
basal; 11, Posterior basal; 12, Inferior lingular;
13, Superior lingular.
(lateral and medial); and the lower lobe (superior, medial basal, anterior
basal, lateral basal and posterior basal).
The left main bronchus is longer than the right main bronchus and makes
an angle of 75° with the vertical. It gives branches to the upper lobe (apico-
posterlor and anterior); the lingular lobe (superior and inferior); and the
lower lobe (superior, lateral basal, posterior basal, medial basal and anterior
basal). These are shown on Figs. 105 and 106.
The bronchoscopist must be familiar with the detailed anatomy of the
bronchial tree so that when he looks at a segmental bronchus he knows
precisely to which portion of the lung it leads. The branches detailed form the
basic anatomy required for use with the rigid bronchoscope. If the fibreoptic
broncfooscope is used, the fourth generation of the bronchi can be entered, but
a detailed anatomy of these is beyond the scope of this book.
ANAESTHESIA, Bronchoscopy may be performed under local or general
anaesthesia. The technique for local anaesthesia is that described for laryngo-
scopy, and that for general anaesthesia varies with the anaesthetist. It is