ABSTRACT
The diaphragm is the primary muscle of inspiration. It arises from the vertebral column, arcuate ligaments, ribs and sternum to form left (1) and right (2) muscular domes that ascend into the thorax and insert into the central tendon (3) of the diaphragm. The nerve supply to each half is by the left and right phrenic (C3,4,5), respectively. ● Diaphragmatic crura – posteriorly a right muscular
crus (4) arises from the first three lumbar vertebrae, and a left crus (5) from the first two. The crura both ascend to the central tendon, but the right crus moves to the left to sweep around the lower oesophagus (6) and contribute to its physiological cardiac sphincter.
