Functional Views of the Wrist

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Introduction

Functional radiography of the wrist (syn. dynamic views) can be somewhat of a mystery to radiographers. A knowledge of the objectives of these views can assist the radiographer to execute the views appropriately and assist in making the radiography a meaningful experience.


Objective of Functional Views of the Wrist

"Carpal ligament instabilities are conditions in which carpal bones have become unstable because of abnormal ligament support. In general, two types of carpal instabilities exist, static and dynamic. Static instabilities are those that are constantly present and that can be recognised on a routine radiographic examination. Dynamic instabilities are present transiently and require stress or motion to produce them." ( Gilula, L.A. and Totty, W.G., The Traumatised Hand and Wrist, Radiographic and Anatomic Correlation, 1992, p232).


Summary of Functional Views of the Wrist
View
Comment
Standard Neutral PA and lateral viewsThese are probably the underestimated views. There is a specific technique for standard neutral wrist views when the aim is to assess alignment, make measurements or asses functionality of the wrist
PA/AP Clenched fistThis technique potentially increases the scapho-lunate distance and has an affect on ulnar variance. Can be performed PA, AP or both.
Radial Deviation and Ulnar Deviation- ulnar deviation, increases scapholunate gap
- radial deviation, closes gap
Flexion and extension lateral
Traction
Dorsal and Ventral Stress
Fluoroscopy/ videofluoroscopy/cineradiography
dynamic CT imaging
wrist arthrography-less commonly performed today



Standard Neutral PA and Lateral Wrist Technique
wrist positioning

<a class="external" href="http://books.google.com.au/books?id=8dSp6Aj0AVQC&pg=PA122&lpg=PA122&dq=gilula+carpal+triquetrum&source=bl&ots=CBwK1_nB5y&sig=SVT1k4NX250yMFT75GCEc0ATr60&hl=en&ei=1MXaSbykKJCCkQXolKjWCA&sa=X&oi=book_result&ct=result&resnum=1#PPA110,M1" rel="nofollow" target="_blank">Examination and Diagnosis of Musculoskeletal Disorders</a>


wrist positioning

<a class="external" href="http://www.radiologyassistant.nl/en/42a29ec06b9e8" rel="nofollow" target="_blank">Louis A. Gilula and Ileana Chesaru Wrist - Carpal instability</a>

wrist positioning






Clenched Fist PA Wrist
Neutral Position
terry thomas sign
Clenched Fist
terry thomas sign
This patient was referred from orthopaedic clinic for assessment of the scapholunate ligament. This is a PA image which does not demonstrate any clear increase in the scapholunate distance.This is a clenched fist PA wrist image which demonstrates a widening of the scapholunate distance.



Radial Deviation and Ulnar Deviation

Left Wrist

Ulnar Deviation
ULNAR DEVIATION
Neutral
PA wrist neutral
Radial Deviation
PA wrist radial deviation
Ulnar Deviation
Ulnar deviation views of the carpal bones are most commonly performed for evaluation of the scaphoid in both acute and non-acute situations. Compare the appearance of the scaphoid in ulnar deviation (elongated) with that in radial deviation (foreshortened). Note that this is pure ulnar deviation- no tube angulation.

Negative ulnar variance noted
Neutral
The 3rd metacarpal should be in line with the central axis of the radius
Radial Deviation
Compare the position of the scaphoid and the hamate-triquetral articulation with the ulnar deviation image. In radial deviation the scaphoid is flexed and foreshortened and displays the Signet ring sign.

Also reduction of negative ulnar variance noted.


Right Wrist (same patient as above)

Radial Deviation
right wrist radial deviation
Neutral
right wrist neutral
Ulnar Deviation
right wrist ulnar deviation
Radial Deviation
Note signet ring appearance of scaphoid
Neutral
This is not a perfect position- the 3rd metacarpal is not in line with the midline of the radius
Ulnar Deviation




Ulnar Deviation
ulnar deviation

The carpal bones rotate about a point located within the capitate. The proximal carpal row moves in the opposite direction to the distal carpal row. The difference in appearance of the carpal bones between the two images, particularly evident in the change in appearance of the scaphoid, suggests that there is a flexion/extension movement of the carpal bones associated with radial/ulnar deviation.

Scaphoid Movement During Ulnar Deviation
ct dynamic
<a class="external" href="http://books.google.com.au/books?id=67UjC6sFy04C&pg=PA120&lpg=PA120&dq=meniscus+homologue&source=bl&ots=LbhEMWnz-M&sig=yf1l2Js5wqLx8XAzBncGuRnz6Ds&hl=en&ei=D8ETSp6pKtGUkAW0p4T9Dg&sa=X&oi=book_result&ct=result&resnum=11#PPA129,M1" rel="nofollow" target="_blank">Ulrich Lanz, Rainer Schmitt, Wolfgang Buchberger. Diagnostic Imaging of the Hand. 2008</a>
The scaphoid rotates in a dorsal direction during ulnar deviation. This movement is used to advantage in the common PA scaphoid view with ulnar deviation.
Lunate Movement During Ulnar Deviation
dynamic wrist CT
<a class="external" href="http://books.google.com.au/books?id=67UjC6sFy04C&pg=PA120&lpg=PA120&dq=meniscus+homologue&source=bl&ots=LbhEMWnz-M&sig=yf1l2Js5wqLx8XAzBncGuRnz6Ds&hl=en&ei=D8ETSp6pKtGUkAW0p4T9Dg&sa=X&oi=book_result&ct=result&resnum=11#PPA129,M1" rel="nofollow" target="_blank">Ulrich Lanz, Rainer Schmitt, Wolfgang Buchberger. Diagnostic Imaging of the Hand. 2008</a>
The same rotation movement is seen in the lunate during ulnar deviation.
Radial Deviation
radial deviation

<a class="external" href="http://books.google.com.au/books?id=67UjC6sFy04C&pg=PA120&lpg=PA120&dq=meniscus+homologue&source=bl&ots=LbhEMWnz-M&sig=yf1l2Js5wqLx8XAzBncGuRnz6Ds&hl=en&ei=D8ETSp6pKtGUkAW0p4T9Dg&sa=X&oi=book_result&ct=result&resnum=11#PPA129,M1" rel="nofollow" target="_blank">based on </a><a class="external" href="http://books.google.com.au/books?id=67UjC6sFy04C&pg=PA120&lpg=PA120&dq=meniscus+homologue&source=bl&ots=LbhEMWnz-M&sig=yf1l2Js5wqLx8XAzBncGuRnz6Ds&hl=en&ei=D8ETSp6pKtGUkAW0p4T9Dg&sa=X&oi=book_result&ct=result&resnum=11#PPA129,M1" rel="nofollow" target="_blank">Ulrich Lanz, Rainer Schmitt, Wolfgang Buchberger. Diagnostic Imaging of the Hand. 2008</a>

The proximal carpal row moves in the opposite direction to the distal carpal row.

During radial deviation, the proximal carpal row rotates in a palmar direction/flexes.

Scaphoid Movement During Radial Deviation
ct dynamic
<a class="external" href="http://books.google.com.au/books?id=67UjC6sFy04C&pg=PA120&lpg=PA120&dq=meniscus+homologue&source=bl&ots=LbhEMWnz-M&sig=yf1l2Js5wqLx8XAzBncGuRnz6Ds&hl=en&ei=D8ETSp6pKtGUkAW0p4T9Dg&sa=X&oi=book_result&ct=result&resnum=11#PPA129,M1" rel="nofollow" target="_blank">Ulrich Lanz, Rainer Schmitt, Wolfgang Buchberger. Diagnostic Imaging of the Hand. 2008</a>
The scaphoid seen here on CT imaging moves in a palmar direction during radial deviation.
Lunate Movement During Radial Deviation
ct wrist dynamic
<a class="external" href="http://books.google.com.au/books?id=67UjC6sFy04C&pg=PA120&lpg=PA120&dq=meniscus+homologue&source=bl&ots=LbhEMWnz-M&sig=yf1l2Js5wqLx8XAzBncGuRnz6Ds&hl=en&ei=D8ETSp6pKtGUkAW0p4T9Dg&sa=X&oi=book_result&ct=result&resnum=11#PPA129,M1" rel="nofollow" target="_blank">Ulrich Lanz, Rainer Schmitt, Wolfgang Buchberger. Diagnostic Imaging of the Hand. 2008</a>
Similarly, the lunate rotates in an palmar direction during radial deviation


Flexion and Extension
Extension
lat wrist extension
Neutral
lat wrist neutral
Flexion
lateral wrist flexion
Extension
NeutralFlexion



Wrist Traction View


"An additional radiographic examination that may provide valuable information about broken arcs and fractures is the view obtained during reduction with finger traction applied. This view can display additional unsuspected avulsion fractures. Because traction stresses intercarpal ligaments and surrounding soft tissues, the traction view may allow detection of previously unrecognised abnormal carpal arcs."


Gilula, L.A. and Totty, W.G., The Traumatised Hand and Wrist, Radiographic and Anatomic Correlation, 1992, p225).









Dynamic CT imaging of the Wrist
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Fluoroscopy/Cineradiography

Wolfgang Hintringer considered cineradiography to be the "... method par excellence for diagnosing dynamic carpal instability". <a class="external" href="http://books.google.com.au/books?id=bITN6PM-fWkC&pg=PA61&lpg=PA61&dq=functional+views+of+the+wrist+radiography&source=bl&ots=sWMknoHcbg&sig=rtdjKYVhNxlNO2qa88PzU0xCoEE&hl=en&ei=1BMSSum2OqX26gPkyYi7Dg&sa=X&oi=book_result&ct=result&resnum=3#PPA69,M1" rel="nofollow" target="_blank">(Wolfgang Hintringer, Cineradiography as a tool to assess wrist instability, in Ueli Büchler, Wrist Instability, 1996)</a>. Functional CT imaging of the wrist has arguably taken this mantle. Hintringer describes the technique as follows

<a class="external" href="http://books.google.com.au/books?id=bITN6PM-fWkC&pg=PA61&lpg=PA61&dq=functional+views+of+the+wrist+radiography&source=bl&ots=sWMknoHcbg&sig=rtdjKYVhNxlNO2qa88PzU0xCoEE&hl=en&ei=1BMSSum2OqX26gPkyYi7Dg&sa=X&oi=book_result&ct=result&resnum=3#PPA69,M1" rel="nofollow" target="_blank">(Wolfgang Hintringer, Cineradiography as a tool to assess wrist instability, in Ueli Büchler, Wrist Instability, 1996)</a>.

wrist fluoroscopy


Comment

Functional radiographic views of the wrist need to be performed to a high standard in order to be diagnostically useful. A knowledge of the positioning requirements and the pathologies demonstrated will assist the radiographer to produce diagnostic images.

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