[Up]    Muscles of the Thoracic wall   [Abdominal mm.]

The external abdominal oblique muscle (A), has been transected to expose the ribs and intercostal muscles. The outer most intercostal muscles, the external intercostal muscles (B), consist of muscle fibers that course in the same direction as those of the external abdominal oblique muscle, caudoventrally. Likewise, the fibers of the underlying internal intercostal muscles (C), course in the same direction as the internal abdominal oblique muscle fibers. As you recall from lab, deep to the internal intercostal muscles is a fibrous layer, the endothoracic fascia. This fascia is the connective tissue which supports the mesothelium lining the thoracic cavity, the pleura. The mesothelium is what type of tissue? (scroll down for answer)

The mesothelium is simple squamous epithelium.