Structure
The costal pleura covers the internal aspect of the sternum, the ribs, and the vertebral bodies, as well as the innermost intercostal muscles and costal cartilages. It begins along the posterior aspect of the sternum, where it is a continuation of the mediastinal pleura. On the right, it reaches the xiphisternal joint, while on the left it diverges laterally due to the presence of the left ventricle and creates the cardiac notch of the left lung.
On both sides, the costal pleura continues laterally, following the curvature of the ribs and covers the sympathetic trunk and splanchnic nerves. When it reaches the lateral aspect of the vertebral bodies, it becomes continuous with the mediastinal pleura again.
Key Features/Anatomical Relations
The costal pleura continues inferiorly along the rib cage to the inferior border where it is continuous with the diaphragmatic pleura. Above the first rib, the costal pleura continues superiorly as the cervical pleura. External to the costal pleural is an additional fascial layer called the endothoracic fascia. This layer is akin to the endoabdominal fascia lining the abdominal wall.
