Structure/Morphology
The internal intercostal membrane (posterior intercostal membrane) is the thin aponeurosis that arises from the posterior end of the internal intercostal muscles. Its fibers travel inferomedially, parallel to those of the internal intercostal muscles, and are attached to the superior and inferior borders of necks and bodies of the ribs and the superior costotransverse ligaments.
Anatomical Relations
The internal intercostal membrane is found within the intercostal spaces of the ribs, where it extends from the angles of the ribs to the superior costotransverse ligaments.
It is located:
- superficial to the subcostal muscles, the anterior rami of thoracic nerves (intercostal nerves), and the intercostal vessels;
- deep to the external intercostal muscles;
- lateral to the superior costotransverse ligaments.
Function
The internal intercostal membrane provides structural support to the intercostal spaces.
