Page 42 - Clinical Anatomy

ECA1 7/18/06 6:31 PM Page 27

The lower respiratory tract 27

Fig. 21◊(a) The segments of the right lung. (b) The segments of the left lung.

The left upper lobe has a lingular segment, supplied by the lingular
bronchus from the main upper lobe bronchus. This lobe is equivalent to the
right middle lobe whose bronchus arises as a branch from the main bronchus.
Apart from this, differences between the two sides are very slight; on the
left, the upper lobe bronchus gives off a combined apicoposterior segmen-
tal bronchus and an anterior branch, whereas all three branches are sepa-
rate on the right side.
On the right also there is a small medial (or cardiac) lower lobe