Chapter 28: Diaphragm

INTRODUCTION

The diaphragm, the most important muscle of respiration, separates the thorax and the abdomen. It can be injured in isolation or involved with injury in either body cavity, and the most challenging concern is the identification of injury. Initially the injury may be asymptomatic with later development of herniation and strangulation of the stomach or other viscera.

HISTORY

Traumatic diaphragmatic rupture was first reported by Sennertus in 1541, and Ambroise Paré was the first to report a series of diaphragmatic perforations found at autopsy.¹ Paré also described gastric and colonic incarceration in a ruptured diaphragm and the consequences.² The diagnosis was made in an antemortem fashion for the first time by Bowditch in 1853,³ and it was not until 1886 that Riolfi was credited with the first successful repair.⁴ The first acute repair by Walker in 1899 was in a patient who had been struck by a falling tree.⁵ The largest early review of 378 diaphragmatic hernias was by Hedblom in 1925.⁴

ANATOMY

The diaphragm is a dome-shaped musculofibrous septum separating the abdomen and thorax. It is bounded above by both pleural spaces and the pericardium, which is attached to the central tendon. Structures immediately adjacent to the inferior side of the diaphragm include the liver, spleen, stomach, and to varying degrees the colon, omentum, and small bowel. The origin of the diaphragm includes the lower sternum, lower six costal cartilages and adjacent ribs, and medial and lateral lumbocostal arches. The crura, two tendinous pillars, arise from the lumbar vertebrae. The insertion of the diaphragm is into the central tendon, an aponeurosis, located at the top of the dome, oriented transversely, and separated into three segments. At rest the diaphragm rises to the level of the fourth intercostal space on the right and the fifth intercostal space on the left. At maximal contraction the diaphragm descends two rib spaces bilaterally. The aorta passes behind the diaphragm and between the crura where it has no attachments. Along with the aorta the thoracic duct and azygous vein pass through this opening. The esophagus traverses the esophageal hiatus mostly composed of the right crus along with the vagus nerves. The inferior vena cava passes through its hiatus at the junction of the right and middle leaflets of the central tendon to which it may be adherent (Fig. 28-1).

The blood supply to the diaphragm is multiply redundant making necrosis extremely rare.⁶ The major source of blood supply to the abdominal side of the diaphragm is the inferior phrenic arteries, which are branches of the abdominal aorta or celiac trunk. Additional blood supply is ...