The interosseous membrane of the forearm (rarely middle or intermediate radioulnar joint) is a fibrous sheet that connects the radius and the ulna. It is the main part of the radio-ulnar syndesmosis, a fibrous joint between the two bones.
The Role of the Interosseous Membrane:
The interosseus membrane divides the forearm into anterior and posterior compartments, serves as a site of attachment for muscles of the forearm, and transfers forces from the radius, to the ulna, to the humerus.
Movement from Pronation to Supination:
As the forearm moves from Pronation to Supination the Interosseous membrane fibres change from a relaxed state, then become tense in the neutral position and then once again become relaxed as the forearm enters Supination.