MODIFICATIONS OF THUMB RADIOGRAPHY

1. it help project the soft tissue of the hand away from the 1st CMC joint. 2. it opens the joint space

The angulations of the central ray serves 2 purposes.

arthritic changes, fractures.

Best demonstrate dislocation of the 1st CMC joint

Best demonstrate base of 1st metacarpal for ruling out

Bennett’s fracture.

the 2 purposes of The angulations of the central ray Commonly performed to demonstrate _.

BENNETT’S FRACTURE

Longitudinal fracture at the base of the 1st

metacarpal with the fracture line entering the

carpometacarpal joint.

Includes posterior dislocation or sublaxation.

BENNETT’S FRACTURE

0 degrees to CMC joint

Robert method

15 degrees proximal to CMC joint

Long-Rafert modification

10 to 15 degrees proximal to MCP joint.

Lewis modification

MODIFICATIONS OF THUMB RADIOGRAPHY

Part Position

– Rotate the arm internally to place the posterior aspect

of the thumb on the IR.

– Hyperextend the hand so that the soft tissue over the

ulnar aspect does not obscure the 1st CMC joint.

Robert’s Method

Perpendicular to the 1st carpometacarpal joint (CMC).

Long and Rafert

15° Proximally along the long axis of the thumb and

entering the 1st carpometacarpal joint (CMC).

Lewis Modification

10°-15° proximally along the long axis of the thumb and

entering the 1st metacarpophalangeal joint (MCP).