Abstract
- The diaphragm consists of a peripheral muscular segment and central aponeurotic segment. It is attached to the lower sternum, the lower six ribs, and the lumbar spine. During expiration it reaches the level of the nipples. The central tendon of the diaphragm is fused to the base of the pericardium.
- It has three major openings, which include the aortic foramen – which allows passage of the aorta, the azygos vein, and the thoracic duct – the esophageal foramen for the esophagus, and the vagus nerves, and finally the vena cava foramen, which contains the inferior vena cava (Figure 19.1).
- The arterial supply stems from the phrenic arteries that are direct branches off of the aorta as it exits the hiatus, while the venous drainage is directly into the inferior vena cava.
- The diaphragm is innervated by the phrenic nerve, which originates from the C3–C5 nerve roots, courses over the anterior scalene muscle, continues into the mediastinum along the pericardium, and terminates in the diaphragm.
Surgical Anatomy
The diaphragm consists of a peripheral muscular segment and central aponeurotic segment. It is attached to the lower sternum, the lower six ribs, and the lumbar spine. During expiration it reaches the level of the nipples. The central tendon of the diaphragm is fused to the base of the pericardium.
It has three major openings, which include the aortic foramen – which allows passage of the aorta, the azygos vein, and the thoracic duct – the esophageal foramen for the esophagus, and the vagus nerves, and finally the vena cava foramen, which contains the inferior vena cava (Figure 19.1).
The arterial supply stems from the phrenic arteries that are direct branches off of the aorta as it exits the hiatus, while the venous drainage is directly into the inferior vena cava.
The diaphragm is innervated by the phrenic nerve, which originates from the C3–C5 nerve roots, courses over the anterior scalene muscle, continues into the mediastinum along the pericardium, and terminates in the diaphragm.
General Principles
The diagnosis of isolated, uncomplicated diaphragmatic injuries can be challenging because they are often asymptomatic and the radiological findings may be subtle or absent.
Untreated diaphragmatic injuries may result in a diaphragmatic hernia, which can manifest long after the injury (Figure 19.2a and 19.2b).
Traumatic diaphragmatic hernias occur almost always in the left diaphragm, although in rare cases they may occur in right-sided large diaphragmatic tears due to blunt trauma or small anterior stab wounds.
The most common herniating viscera include the omentum, stomach, and colon. Less often, the spleen and the small bowel may herniate through an unrepaired diaphragmatic injury.
A diaphragmatic hernia may cause bowel obstruction or result in ischemic necrosis of the herniating viscus. These conditions are associated with significant morbidity and mortality.
In penetrating injuries, the diaphragmatic tear is about 3–4 cm. In blunt trauma it is significantly larger, at about 7–8 cm (Figures 19.3a and 19.3b).
Figure 19.2 (a, b) Left diaphragmatic hernia with stomach and colon in the left chest, following a stab wound to the left thoracoabdominal area many years previously.
Figure 19.3
(a) Penetrating injury to the left diaphragm (circle). The laceration in penetrating trauma is fairly small, usually about 3–4 cm long.
