Interosseous membrane of the forearm: an anatomical study of ligament attachment locations.

PURPOSE:
The interosseous membrane (IOM) of the forearm is a stout ligamentous complex that reportedly comprises several ligamentous components. The purpose of this cadaveric study was to define all IOM ligaments and to clarify the precise attachment locations.

METHODS:
Thirty forearms from 15 embalmed cadavers were used. After dissection, all IOM ligaments were identified, and attachments were measured from the tip of the radial styloid or the ulnar head. Attachment locations were represented as a percentage of total bone length from the distal end of the radius or ulna.

RESULTS:
The IOM included 5 kinds of ligaments: central band, accessory band, distal oblique bundle, proximal oblique cord, and dorsal oblique accessory cord. The most distal and proximal ends of the radial origin of the central band were 53% and 64% of total radial length from the tip of the radial styloid, whereas those of the ulnar insertion were 29% and 44% of total ulnar length from the ulnar head. The center point of the radial origin and ulnar insertion of the accessory band were 37% and 23%, respectively. The center points of the ulnar origins and radial insertions were 15% and 10% for the distal oblique bundle; 80% and 79% for the proximal oblique cord; and 64% and 62% for the dorsal oblique accessory cord, respectively.

CONCLUSIONS:
The present study clarified precise attachment locations of all representative IOM ligaments. This information will be useful in planning proper graft placement in ligament reconstruction surgery and for future biomechanics research into the function of the IOM ligaments.