PA Wrist Image Critique
In ulnar deviation the lunate is positioned _____ to the ______.
Distal Radius
If the wrist is _____ as of result of hand extension or is ______ flexed, the ____ is foreshortened.
Flexed Radially flexed Scaphoid
What increases the visibility of the pisiform and hamate hook?
Internal rotation of the wrist
Excessive flexion to overlap and obscure metacarpals with digits. True or false.
NO excessive flexion to overlap and obscure
When the hand is in a _____ projection, the ______ styloid is in profile.
PA projection Radial styloid
When the hand and wrist are rotated externally into a PA Oblique projection, what happens to the wrist anatomy?
Carpals and metacarpal bases on the medal aspect of the wrist are superimposed Lateral carpals and metacarpals are not superimposed and joint spaces are open
Anterior and posterior carpal articulating margins of the _______ are nearly superimposed.
Radius
The lunate becomes ______ with hand extension and flexion.
Triangular
If the distal scaphoid tilts posteriorly and demonstrates decreased foreshortening and the lunate shifts laterally towards the radius, what positioning error has occurred?
Ulnar deviation of the wrist
How much wrist flexion is needed to open the carpometacarpal joints?
10-15 degrees with the IR
What is the significance of the scaphoid fat stripe?
A change in the normal convexity of the stripe indicates joint effusion or, of a radial side fracture of the scaphoid, radial styloid process or proximal first metacarpal
What brings the ulnar styloid in profile and aligns the radius and ulna parallel with each other?
Abducting the humerus to position the elbow in a lateral projection with the humeral epicondyles perpendicular to the IR
What is the normal shape of the scaphoid fat stripe?
Convex
What anatomy should be visualized on a PA wrist?
Distal radius and ulna (2.5"), carpal bones and proximal half of metacarpals
In radial deviation the lunate is positioned ______ to the _____ joint.
Distally Radioulnar joint
If the wrist is _____ as a result of hand flexion or is _____ flexed, the _______ is demonstrated with decreased foreshortening.
Extended Ulnar-flexed Scaphoid
The lateral carpals and metacarpals will be superimposed when the wrist is positioned how?
Internally rotated
Radial and ulnar styloid are at extreme ________ and ________ edges
Lateral and medial
When the elbow is in a _______ position and the epicondyles are are ________ to the IR, the _____ styloid is in profile.
Lateral position Perpendicular Ulnar styloid
where is the scaphoid fat stripe located and when is it seen?
On the lateral side of the scaphoid on all PA wrist X-rays
No _______ in the carpals, metacarpals, or radius
Rotation
Adequate density demonstrated by _______ and bony ________
Soft tissue and bone trabeculation
What positioning error occurred if the anterior radial margin is shown distal to the posterior radial margin?
The distal forearm is elevated higher then the proximal forearm
Signet ring appearance of the scaphoid is shown on a PA wrist, what positioning error occurred?
The hand is extended Curl the fingers to flex the metacarpals 10-15 degrees to fix
What determines the placement of the ulnar styloid?
The humerus and elbow positioning
If the ulnar styloid is no longer in profile, what positioning error occurred?
The humerus is not abducted, the radius and ulna are crossed over each other, the epicondyles are parallel to the IR instead of perpendicular
If the radius is foreshortened, excessive amounts of radial articular surface and superimposition of the scaphoid and lunate onto the radius is greater, what positioning error has occurred?
The patient has a thick proximal forearm Let the proximal forearm extend off the back of the IR or position the forearm parallel to the IR
To superimpose the the distal radial margins and to demonstrate open radioscaphoid and radiolunate joints open, what position needs to be met?
The proximal forearm should be positioned slightly lower (5-6 degrees) than the distal forearm
If a PA wrist projection shows the posterior radial margin distal to the anterior margin, what positioning error occurred?
The proximal forearm was elevated higher then the distal forearm
Wrist ulnar or radial deviation is identified by evaluating the alignment of?
The third metacarpal with the radius
What position is the patients wrist in, if the long axis of the third metacarpal and forearm are aligned with the long axis of the collimated light?
The wrist is in a neutral position
The radial styloid is rotated out of profile and the radioulnar articulation is closed, what positioning error has occurred?
The wrist is internally or externally rotated
If the posterior radial margin is superimposed over the ulna, what positioning error occurred?
The wrist is medially rotated
If the distal scaphoid shifts anteriorly, the lunate shifts medially and the scaphoid appears as a signet ring, what positioning error has occurred?
The wrist is radially deviated and the scaphoid is foreshortened
Radial and ulnar deviated PA wrist projections may be requested when?
The wrist joint mobility is in question
What positioning error results in forshortened metacarpals, closed 2nd-3rd carpometacarpal joint spaces, decreased scaphoid foreshortening and a triangular shaped lunate?
Wrist extension