Wrist and Forearm Positioning
when do we not use ulnar deviation
With severe pain, hand is not everted
in a PA wrist projection what is located vertically next to the radius?
Fat Stripe
where is the cr in inferosuperior position
central ray angled 25º-30º to long axis of hand
A radiograph of the PA scaphoid projection in ulnar flexion reveals extensive superimposition of the scaphoid and adjacent carpals
Insufficient ulnar flexion can lead to this problem.
describe a power grip PA projection
hand everted and clinched in a fist; CR is 90º (perpendicular) to IR
patient position for power grip projection
hand everted and clinched in a fist; CR is 90º (perpendicular) to IR
Patient position for wrist
90* angle from Ir shoulder, elbow and wrist in the same plane
what does the AP wrist projection demonstrate
AP projection best demonstrates the carpal interspaces.
A patient enters the ER with a possible scaphoid fracture. The patient is unable to assume the ulnar flexion position
modified stecher position with the CR angled 20° toward the elbow could be performed to confirm a scaphoid fracture
structures shown for wrist projection
Carpals, distal radius and ulna, and proximal metacarpals
how is the cr in superoinferior projection
CR is 90º to IR
A radiograph of a tangential, inferosuperior projection of the carpal canal reveal that the hamate is superimposed over the pisiform
Repeat the exposure rotating the wrist and hand 10° internally
What on the scaphoid should be demonstrated in a PA wrist oblique
tuberosity of the scaphoid should be demonstrated.
describe the humerus in a lateral forearm
- Distal humerus is in a lateral position
how should the radius and ulna be in a lateral wrist
The radius and ulna should be superimposed.
In a AP forearm, the radius and ulna should not be___________
The radius and ulna should not be superimposed distally
in a lateral wrist, where the ulnar styloid be seen
The ulnar styloid should be demonstrated in profile posteriorly
where is the CR angled in the carpal bridge/ tangenital projection
- CR angled 45º to long axis of forearm ;1 ½ " proximal to wrist joint
what are the structures shown in a carpal bridge projection
- Carpal bridge - Fractures of the scaphoid and dorsal aspect - Chip fractures, calcifications of dorsal carpal, and foreign bodies on dorsum of carpals bones
what does the gaynor hart method projection show?
- Carpal canal (tunnel) in arched arrangement - Entire pisiform in profile - "Hook" (hamular process) of hamate - Calcifications in carpal sulcus (groove)
what structures are shown in a radial flexion projection
- Carpal interspaces on the ulnar (medial) side of wrist
structures shown in a ap oblique wrist
- Carpals - Pisiform seen in profile, free of superimposition
what are the structures shown in a oblique PA wrist projection
- Carpals on lateral (radial) side of wrist, particularly the scaphoid (navicular) and trapezium
structures shown in a lateral wrist
- Carpals, proximal metacarpals, and distal radius and ulna superimposed - Anterior displacement (Smith) and posterior displacement (Colles) of fractures of radius
where is the central ray for ulnar deviation
- Centered to scaphoid - PA: 90° to IR
what part of the humerus should be in profile for a ap forearm projection
- Epicondyles of the humerus should be seen in profile
how do you perform a modified method of a carpal bridge/ tangenital projection
- Forearm elevated on support device; wrist flexed to right angle; IR placed vertically against back of hand
what structures are shown in a ap forearm
- Forearm including both elbow and wrist joints
PA oblique part position?
- From pronated position, rotate wrist laterally to form 45º angle with IR - Wrist in semipronation
Part position for wrist
- Hand pronated; fingers arched - Midcarpal area centered to IR
describe the humeral epicondyles in a lateral forearm projection
- Humeral epicondyles should be superimposed and perpendicular to the IR.
central ray for wrist
- Perpendicular to midcarpal area
how is the central ray in a AP oblique wrist
- Perpendicular to midcarpal area
where should the central ray be for a lateral forearm
- Perpendicular to midpoint of forearm
where is the central ray in a ap forearm
- Perpendicular to midpoint of forearm
what parts of the hand are shown in a ulnar deviation projection
- Scaphoid not foreshortened; opens carpal interspaces on radial (lateral) side of wrist
patient position for a ap forearm
- Seated - Entire upper extremity in same plane
patient position in a lateral wrist
- Seated, elbow flexed 90° - Entire upper limb in same plane
PA Oblique patient position?
- Seated, elbow flexed 90° - Hand and forearm resting palm down
smiths fracture of radius
Anterior displacement
what is the part position for a lateral forearm
Elbow flexed 90º; forearm centered to IR - Hand and wrist in lateral position - Distal radius and ulna superimposed - Humeral epicondyles superimposed
what structures should be shown in a lateral forearm
Forearm including both elbow and wrist joints
part position for AP oblique wrist
From supine position, rotate wrist medially to form a 45º angle with IR - Wrist in semisupination
what is a variation in the modified stecher method
Hand everted in ulnar flexion; elevated 20° on sponge; CR 90º (perpendicular) to IR
part position for a ap forearm
Hand in supination; patient leans laterally - Centered to midpoint of forearm - Humeral epicondyles parallel to IR
what is part position for ulnar deviation
Hand pronated - Evert hand (turn outward), flexed toward ulna
part position for radial flexion
Hand pronated - Invert hand (turn inward), flexed toward radius
Where is the central ray in a oblique wrist projection
Perpendicular to midcarpal area
where is the central ray in a lateral wrist
Perpendicular to midcarpal area
where is the central ray in a radial flexion projection
Perpendicular to midcarpal area
what is patient position for ulnar deviation
Seated - Entire upper limb in same plane
patient position for AP oblique wrist
Seated - Forearm in supine position
patient position for radial flexion projection
Seated, elbow flexed 90° - Entire upper limb in same plane
anteriorly, __________ should be seen in a lateral wrist
The anterior (pronator) fat stripe should be seen.
how should the sacphoind and pisiform be in a lateral wrist
The distal end of the scaphoid and the pisiform should be superimposed
how should the radius and ulna be in a lateral forearm
The distal radius and ulna should be superimposed.
what joint space should be open in a lateral forearm projection
The elbow joint space should be open, and the head of the radius should be superimposed over the coronoid process
in a lateral wrist, what should there not be between the trapezium and the base of the 1st metacarpal?
The joint space between the trapezium and the base of the 1st metacapral should be free of superimposition
in a lateral wrist the, what should be aligned with the forearm
The long axis of the first metacarpal should be aligned parallel with the forearm
part position in a lateral wrist
The medial aspect of arm is adjacent to the IR - Wrist true lateral (distal radius and ulna superimposed) - Carpals centered to IR
how are the medial carpals in a pa wrist projection
The medial carpals are superimposed
In a PA oblique wrist projecion the trapezium and trapezoid should be how
The trapezium and trapezoid should be demonstrated without superimposition.
in a Modified Stecher Method, how is the wrist and what is the CR angle?
Wrist horizontal (parallel); CR angled proximally 20
describe superoinferior projection patient position
Wrist is dorsiflexed with palm resting on IR; patient leans forward to place carpal canal in profile;
describe patient position inferosuperior projection
Wrist is hyperextended (dorsiflexed) with long axis of hand as vertical as possible; rotate hand 10° internally; forearm horizontal;
in a modified stecher method how is the wrist positioned
Wrist positioned as for a PA projection
in a PA wrist the radius and ulna are
are separated, the distal radioulnar joint is open
The physician wants to rule out abnormal calcifications in the dorsal carpal
carpal bridge method would best demonstrate this region
A patient with a history of carpal tunnel syndrome comes to radiology. The physician wants to rule out abnormal calcifications in the carpal canal
gaynor-hart method would best demonstrate this region
in a PA wrist projection the navicular is:
is foreshortened
in a PA wrist projection the trapezoid is:
is superimposed on the trapezium
colles fracture of radius
posterior displacement (Colles)
carpal bridge method is also known as the :
tangenital projection
