The anterior diaphragmatic attachments: an anatomic and radiologic study with clinical correlates.

A study of the anterior attachments of the respiratory diaphragm was performed using gross anatomic specimens, plain radiography, and computed tomography with multiplanar image reformatting. The anterior portions of the diaphragm are affixed to the lower six ribs and the sternum. The line of attachment of each hemidiaphragm begins at the anterior axillary line and extends cranially and medially to meet at the xiphoid process. These structures can be visualized along with contiguous pathologic subdiaphragmatic and/or infradiaphragmatic air collections. In the semierect patient, free intraabdominal air may preferentially collect in the anterior subdiaphragmatic regions rather than below the domes of the diaphragm, providing a subtle but reliable indication of pneumoperitoneum. An understanding of the normal anatomy of the anterior diaphragmatic attachments is valuable in assessing a variety of anterior paradiaphragmatic air collections.