Upper Limb Radiography: Wrists and Scaphoids

Flashcards covering positioning criteria, anatomical landmarks, exposure adjustments, and fracture types for wrist and scaphoid radiography.

DP Wrist Centre Point

Located in the midline, midway between the Radial and ulna styloid process, or at the mid carpal level.

DP Wrist Rotation Criteria

Equal concavity of the metacarpals (MCs) and minimal superimposition of the metacarpal bases and the distal radio-ulnar joint.

Oblique Wrist Rotation

The patient's hand is externally rotated $45^{\circ}$ onto the image detector.

Lateral Wrist Centre Point

The radial styloid process, specifically more over the lunate bone, slightly distal to the styloid.

Apple, Cup, and Saucer Alignment

A visual tool for the lateral wrist where the capitate (apple) sits in the lunate (cup), which sits in the distal radius (saucer).

PA Scaphoid Centre Point

The midcarpal area, which can be identified as $2\,cm$ distal and lateral to the radial styloid process.

Ulnar Deviation

The lateral movement of the wrist used in scaphoid projections to open carpal bones and bring neighboring bones away from the scaphoid for better visualization.

Lateral and Axial Scaphoid Centre Point

The Anatomical Snuff Box (ASB), located distal to the radial styloid process.

Axial Scaphoid Angulation

A $25^{\circ}$ cranial tube angle used to elongate the scaphoid bone and keep it free of superimposition.

Cast Exposure Adjustment

To maintain diagnostic quality through a cast, the technique is increased; for example, from $55\,kVp$ and $2\,mAs$ ($EI: 89$) to $60\,kVp$ and $4\,mAs$ ($EI: 336$).

Lateral Wrist Under-rotation Correction

The patient's wrist must be externally rotated (moved posteriorly) slightly to bring the distal radius more over the distal ulna.

Lateral Wrist Over-rotation Correction

The patient's wrist must be internally rotated (moved anteriorly) slightly to bring the distal radius more anterior over the distal ulna.

Scaphoid Fracture Distribution

Occurs in the waist ($70\text{--}80\%$), distal pole ($20\%$), or proximal pole ($10\%$).

Avascular Necrosis

A risk associated with scaphoid fractures which necessitates follow-up even if the fracture is initially occult.

Torus Fracture

A distal radial metaphysis fracture typically occurring in children aged $4\text{--}10$ years following a FOOSH.

Salter-Harris II Fracture

A fracture involving the physeal plate typically occurring in adolescents aged $11\text{--}16$ years following a FOOSH.

Colles Fracture

Common in patients over $40$ years; a fracture of the distal radial metaphyseal region with dorsal (posterior) angulation and displacement.

Dinner Fork Deformity

A clinical description of a Colles fracture where the dorsal angulation is severe.

Smith's Fracture

Also called a reverse Colles; a fracture of the distal radius with volar (anterior) angulation of the distal fragment, usually resulting from a fall onto a flexed wrist.

FOOSH

An acronym for 'Fall On the Out-Stretched Hand,' a common mechanism of injury for wrist and scaphoid fractures.