Wednesday 25 April 2012

Wrist

PA

Indications for imaging
Injury, pain, carpal tunnel syndrome,
Anatomy  Demonstrated
Distal radius and Ulna, carpal bones and proximal metacarpals.

Wrist Lt Anatomy
Meschan, I. 1955 An Atlas of Normal Radiographic Anatomy Saunders, London
Basic Patient Position
The patient sits alongside the long edge of the table arm extended palm downwards, or at the end of the table with he elbow flexed at 90 degrees, hand and wrist flat on the cassette with the fingers flexed to maximise contact of the wrist with the cassette.
Wrist Lt PA Patient Position
Meschan, I. 1955 An Atlas of Normal Radiographic Anatomy Saunders, London

Radiation protection
Direct lead rubber gonad protection using a "half apron".
Ensure the lower limbs and torso are not below the table top in the primary beam.
Central Ray
The vertical central ray is centered to midway between the medial and lateral skin margins to the mid carpal region approximately 1 cm distal to the ulna styloid process.
Exposure Factors
Kv mAS FFD (cm) Grid Focus AEC Cassette
60 4 100 No Fine No 18 x 24 cm
Plaster cast will need approximately 10 kv more when wet 5 Kv more when dry.
Evaluation of the Image
ID and markers must be present and correct in the appropriate area of the film
Evidence of collimation on four sides equally around the centering point.
Limits of the examination, superiorly the lower quarter of the radius and ulna, distally the metacarpals, lateral and medially the skin margins.
The distal radio ulna joint should be visualised, in true DP position the metacarpals should be evenly superimposed.
Exposure, adequate penetration to visualise all bone detail and low enough contrast to visualise the soft tissues.

Wrist Rt DP
http://www.vh.org
Related Projections
Hand DP
Hand DP "Ball catching for rheumatoid)
Hand DP Oblique
Fingers Lat.
Thumb AP
Thumb Lat. Wrist AP
Wrist Lat
Wrist Oblique
Wrist AP Angled for Scaphoid
Additional modalities
M.R.. for internal soft tissue structures, CT may be helpful, RNI for equivocal fractures, macro-radiography for schaphoid.

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