Air gap magnification techniques in upper extremity fractures.

Air gap magnification is useful in the diagnosis of upper extremity fractures specifically as it applies to nondisplaced fractures of the radial head, carpals and metacarpals. These injuries often prove difficult if not impossible to detect on routine roentgenographs. Gap magnification is technically simple to perform, requires no special equipment, and has been useful in evaluating subtle roentgenographic changes.