First Carpometacarpal - AP projection
Burman Method
When hyperextension of the wrist is not contraindicated, Burman method is the best projection to provide a clearer image of the first CMC joint then the standard AP projection as Burman stated.
Image Receptor: 8 X 10 inches, lengthwise
Source to Image Distance (SID)
The recommended distance of SID is 18 inches. This produces a magnified image that creates a greater field of view of the concavoconvex aspect of this joint.
Patient Position
Let patient sit at the end of the radiographic table so that the forearm can be adjusted to lie approximately parallel with the long axis of the IR.
Part Position
- Place the image receptor under the wrist, and center the first CMC joint to the center of the IR.
- Hyperextend the hand, and have the patient hold the position with the opposite hand or with a bandage looped around digits.
- Rotate the hand internally, and abduct the thumb so that it is flat on the IR.
- Shield gonads.
Central Ray:
Through the first CMC joint at a 45 degree angle toward the elbow.
Structure shown:
The radiograph will show a magnified concavoconvex outline of the first CMC joint.
Evaluation Criteria
- The following should be clearly demonstrated:
- First metacarpal
- Trapezium in concave profile
- Base of the first metacarpal in convex profile.
- First CMC joint, unobscured by adjacent carpals.
No comments:
Post a Comment