The cervical pleura can be marked out on the surface by a curved line drawn from the sternoclavicular joint to the junction of the medial and middle thirds of the clavicle; the apex of the pleura is approximately 1 in (2.5 cm) above the clavicle. This fact is easily explained by the oblique slope of the first rib. It is important because the pleura can be wounded (with consequent pneumothorax) by a stab wound – and this includes the surgeon’s knife and the anaesthetist’s needle – above the clavicle, or, in an attempted subclavian vein catheterization, below the clavicle. The lines of pleural reflexion pass from behind the sternoclavicular joint on each side to meet in the midline at the 2nd costal cartilage (the angle of Louis). The right pleural edge then passes vertically downwards to the 6th costal cartilage and then crosses:

• the 8th rib in the midclavicular line;

 • the 10th rib in the midaxillary line;

 • the 12th rib at the lateral border of the erector spinae.

FIG1. The surface markings of the lungs and pleura – anterior view.

FIG2. The surface markings of the lungs and pleura – posterior view.

On the left side the pleural edge arches laterally at the 4th costal cartilage and descends lateral to the border of the sternum, owing, of course, to its lateral displacement by the heart; apart from this, its relationships are those of the right side. The pleura actually descends just below the 12th rib margin at its medial extremity – or even below the edge of the 11th rib if the 12th is unusually short; obviously, in this situation, the pleura may be opened accidentally in making a loin incision to expose the kidney, perform an adrenalectomy or drain a subphrenic abscess.