Basic x ray views of fingers and thumb

Basic x ray views of fingers and thumb
postioning and different ways of doing x ray views of thumb and fingers

1. BASIC X-RAY VIEWS OF FINGERS AND THUMB MAAJID MOHI UD DIN MALIK LECTURER COPMS ADESH UNIVERSITY BATHINDA, PUNJAB

2. FINGERS BASIC PROJECTIONS It is common practice to obtain two projections, a Postero-anterior and a lateral, on one 18 X 24-cm high-resolution cassette. It is often necessary to image adjacent fingers, e.g. the second and third or the fourth and fifth. If this is the case, then care should be taken to avoid superimposition, particularly in the lateral projection, by fully extending one finger and partly flexing the other .

3. CONT…. A non-opaque foam pad is used to support the finger not in contact with the cassette. A lead-rubber mask may be used to mask off the half of the film not in use.

4. POSTERO-ANTERIOR Position of patient and cassette The patient is positioned seated alongside the table as for a Postero-anterior projection of the hand. The forearm is pronated with the anterior (palmer) aspect of the finger(s) in contact with the cassette. The finger(s) are extended and separated. A sandbag is placed across the dorsal surface of the wrist for immobilization.

5. DIRECTION AND CENTRING OF THE X-RAY BEAM The vertical central ray is centred over the proximal interphalangeal joint of the affected finger.

6. ESSENTIAL IMAGE CHARACTERISTICS The image should include the fingertip and the distal third of the metacarpal bone.

7. POSITIONING

8. POSTERO-ANTERIOR RADIOGRAPH OF THE INDEX AND MIDDLE FINGERS

9. LATERAL – INDEX AND MIDDLE FINGERS Position of patient and cassette T he patient is seated alongside the table with the arm abducted and medially rotated to bring the lateral aspect of the index finger into contact with the cassette. The raised forearm is supported.

10. CONT… The index finger is fully extended and the middle finger slightly flexed to avoid superimposition. The middle finger is supported on a non-opaque pad. The remaining fingers are fully flexed into the palm of the hand and held there by the thumb.

11. DIRECTION AND CENTRING OF THE X-RAY BEAM The vertical central ray is centred over the proximal interphalangeal joint of the affected finger.

12. ESSENTIAL IMAGE CHARACTERISTICS The image should include the fingertip and the distal third of the metacarpal bone. The condyles should be superimposed to avoid obscuring a volar plate fracture.

13. POSITIONING

14. LATERAL RADIOGRAPH OF INDEX AND MIDDLE FINGERS

15. LATERAL – RING AND LITTLE FINGERS Position of patient and cassette The patient is seated alongside the table with the palm of the hand at right-angles to the table and the medial aspect of the little finger in contact with the film. The affected finger is extended and the remaining fingers are fully flexed into the palm of the hand and held there by the thumb in order to prevent superimposition. It may be necessary to support the ring finger on a nonopaque pad to ensure that it is parallel to the film.

16. DIRECTION AND CENTRING OF THE X-RAY BEAM The vertical central ray is centred over the proximal interphalangeal joint of the affected finger.

17. ESSENTIAL IMAGE CHARACTERISTICS The image should include the tip of the finger and the distal third of the metacarpal bone.

18. NOTE In cases of severe trauma, when the fingers cannot be flexed, it may be necessary to take a lateral projection of all the fingers superimposed, as for the lateral projection of the hand, but centring over the proximal inter-phalangeal joint of the index finger.

19. POSITIONING

20. NORMAL LATERAL RADIOGRAPH OF RING AND LITTLE FINGERS

21. LATERAL RADIOGRAPH OF MIDDLE FINGER SHOWING A FRACTURE OF THE MIDDLE PHALANX

22. LATERAL RADIOGRAPH OF LITTLE FINGER SHOWING DISLOCATION OF THE DISTAL INTERPHALANGEAL JOINT

23. BASIC X-RAY VIEWS OF THUMB It is common practice to obtain two projections, an anteroposterior and a lateral, on one 18 X 24-cm high-resolution cassette. In the case of a suspected foreign body in the thenar eminence, a Postero-anterior projection is used to maintain the relationship with adjacent structures. A lead-rubber mask may be used to mask off the half of the cassette not in use.

24. LATERAL Position of patient and cassette The patient is seated alongside the table with the arm abducted, the elbow flexed and the anterior aspect of the forearm resting on the table. The thumb is flexed slightly and the palm of the hand is placed on the cassette. The palm of the hand is raised slightly with the fingers partially flexed and supported on a non-opaque pad, such that the lateral aspect of the thumb is in contact with the cassette.

25. DIRECTION AND CENTRING OF THE X-RAY BEAM The vertical central ray is centred over the first metacarpophalangeal joint.

26. ESSENTIAL IMAGE CHARACTERISTICS Where there is a possibility of injury to the base of the first metacarpal, the carpo-metacarpal joint must be included on the image.

27. POSITIONING

28. NORMAL LATERAL RADIOGRAPH OF THUMB

29. ANTERO-POSTERIOR Position of patient and cassette The patient is seated facing away from the table with the arm extended backwards and medially rotated at the shoulder. The hand may be slightly rotated to ensure that the second, third and fourth metacarpals are not superimposed on the base of the first metacarpal. The patient leans forward, lowering the shoulder so that the first metacarpal is parallel to the tabletop. The cassette is placed under the wrist and thumb and oriented to the long axis of the metacarpal.

30. DIRECTION AND CENTRING OF THE X-RAY BEAM The vertical central ray is centred over the base of the first metacarpal.

31. POSITIONING

32. NORMAL ANTERO-POSTERIOR RADIOGRAPH OF THUMB

33. POSTERO-ANTERIOR – FOREIGN BODY Position of patient and cassette With the hand in the Postero-anterior position, the palm of the hand is rotated through 90 degrees to bring the medial aspect of the hand in contact with the table and the palm vertical. The cassette is placed under the hand and wrist, with its long axis along the line of the thumb.

34. CONT… The fingers are extended and the hand is rotated slightly forwards until the anterior aspect of the thumb is parallel to the cassette. The thumb is supported in position on a non-opaque pad.

35. DIRECTION AND CENTRING OF THE X-RAY BEAM The vertical central ray is centred to the first metacarpophalangeal joint.

36. ESSENTIAL IMAGE CHARACTERISTICS Where there is a possibility of injury to the base of the first metacarpal, the carpo-metacarpal joint must be included on the image. The second, third, fourth and fifth metacarpals should not be superimposed on the first.

37. NOTES The Postero-anterior projection increases object-to-film distance and hence, potentially, unsharpness, but it is sometimes easier and less painful for the patient. The use of the Postero-anterior projection maintains the relationship of the adjacent bones, i.e. the radius and ulna, which is essential in cases of suspected foreign body in the thenar eminence.

38. POSITIONING

39. Postero-anterior thumb – showing dislocation at the first metacarpophalangeal joint

40. ANTERO-POSTERIOR RADIOGRAPH OF THUMB – INCORRECTLY POSITIONED

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