Upper Extremities
16
Anatomy
Digits, Head, Base, Body or shaft, Phalanges, Metacarpals, Interphalangeal joints, Metacarpophalangeal joints, Trapezium
Projections
Finger, PA
CR Location
Finger, PA – CR perpendicular to IR, directed to PIP joint
Evaluation Criteria
Finger, PA – All phalanges and the distal 1/3 of the metacarpal should be included. Equal concavity of the shafts of the phalanges and metacarpals shows us that there is no rotation. Fingers should be spread apart and joint spaces should be open (indicating correct CR placement)
Finger, Oblique
CR Location
Finger, Oblique – CR perpendicular to IR, directed to PIP joint
Evaluation Criteria
Finger, Oblique – All phalanges and the distal 1/3 of the metacarpal should be included. Fingers should be spread apart. Joint spaces should be open (indicating correct CR placement and that the phalanges are parallel to the image).
Finger, Lateral
CR Location
Finger, Lateral – CR perpendicular to IR, directed to PIP joint
Evaluation Criteria
Finger, Lateral – All phalanges and the metacarpophalangeal joint should be included. Long axis of the finger should be aligned to the long axis of the portion of image being used. Joint spaces should be open (indicating correct CR placement and that the phalanges are parallel to the image).
Thumb, AP
CR Location
Thumb, AP – CR perpendicular to IR, directed to first MCP
Evaluation Criteria
Thumb, AP – All phalanges, the entire metacarpal and the trapezium should be included. Long axis of the finger should be aligned to the long axis of the portion of image being used. Equal concavity of the shafts of the phalanges and metacarpals shows us that there is no rotation. Joint spaces should be open (indicating correct CR placement and that the phalanges are parallel to the image).
Thumb, Medial Oblique
CR Location
Thumb, Medial Oblique – CR perpendicular to IR, directed to first MCP
Evaluation Criteria
Thumb, Medial Oblique – All phalanges, the entire metacarpal and the trapezium should be included. Long axis of the finger should be aligned to the long axis of the portion of image being used. Joint spaces should be open (indicating correct CR placement and that the phalanges are parallel to the image).
Thumb, Lateral
CR Location
Thumb, Lateral – CR perpendicular to IR, directed to first MCP
Evaluation Criteria
Thumb, Lateral – All phalanges, the entire metacarpal and the trapezium should be included. Long axis of the finger should be aligned to the long axis of the portion of image being used. Joint spaces should be open (indicating correct CR placement and that the phalanges are parallel to the image).
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Hows & Whys of Finger Radiography
- Why are fingers obliqued to the side that allows the finger to be closest to the image?
- To prevent magnification. Image contact also reduces patient motion.
- How do you know that a PA finger was not rotated?
- The concavity of the shafts of the phalanges is equal.
- How can you tell that the finger was parallel to the image receptor?
- The joint spaces are open.
- Why should the fingers be kept parallel to the image receptor?
- To prevent foreshortening of the phalanges and to open the joint spaces.