1. On this PA hand, the interphalangeal and metacarpophalangeal joints appear open and the phalanges are not foreshortened. Which positioning step produced this?
Hand
The hand has 27 bones: 14 phalanges, 5 metacarpals and 8 carpals. A routine hand is a PA, a PA oblique and a lateral, centered to the 3rd MCP joint. Fingers and the thumb have their own series (see Fingers & thumb).
Overview
Bones
Phalanges (14)
- Thumb: proximal and distal
- Fingers 2–5: proximal, middle and distal
Metacarpals (5)
- 1st (thumb)
- 2nd
- 3rd
- 4th
- 5th
Joints
- IP / PIP / DIP
- MCP
- CMC
Digits and metacarpals are numbered 1 to 5 starting at the thumb. Each metacarpal has a base (proximal), shaft and head (distal).
Registry must-knows
- Centering: hand at the 3rd MCP joint, a finger at its PIP joint, the thumb at the 1st MCP joint.
- On the oblique, keep the digits parallel to the IR so the IP joints stay open and the phalanges aren't foreshortened.
- Boxer's fracture: the neck of the 5th metacarpal. Bennett fracture: an intra-articular fracture-dislocation at the base of the 1st metacarpal.
- Gamekeeper's (skier's) thumb is an ulnar collateral ligament injury at the 1st MCP joint.
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- Bone age: a PA of the left hand and wrist. The Norgaard (ball-catcher's) view, both hands 45° AP oblique, looks for early rheumatoid arthritis.
3D model
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Radiographs 4
Pick a film, then a structure to circle it.
Projections 3
Tap a projection for positioning, central ray and image criteria. See every exam in the Positioning Guide ›
PA hand
CR: Perpendicular
- Position
- Palm flat on the IR, fingers slightly spread.
- Central ray
- Perpendicular
- Centering
- 3rd MCP joint
- Typical technique
- 55–60 kVp · 2–3 mAs · 40" SID
- Best shows
- All the bones of the hand; the thumb appears oblique
Image criteria
- Entire hand and about 1 inch of the distal radius and ulna included.
- No rotation: equal concavity on both sides of the metacarpal and phalangeal shafts.
- Digits slightly separated; MCP and IP joints open.
PA oblique hand (lateral rotation)
CR: Perpendicular
- Position
- From the PA, rotate the hand 45° laterally, with the digits supported parallel to the IR.
- Central ray
- Perpendicular
- Centering
- 3rd MCP joint
- Typical technique
- 55–60 kVp · 2–3 mAs · 40" SID
- Best shows
- Metacarpal and phalangeal fractures; joint spaces
Image criteria
- Midshafts of the 3rd–5th metacarpals don't overlap; slight overlap of their heads is normal.
- IP and MCP joints open (digits parallel to the IR).
- No more than 45° of rotation.
Lateral hand
Fan lateralCR: Perpendicular
- Position
- Ulnar side down, hand in a true lateral. Fan the fingers on a step sponge to see the phalanges, or keep them together (extension) for a foreign body or metacarpal displacement.
- Central ray
- Perpendicular
- Centering
- 2nd MCP joint
- Typical technique
- 55–60 kVp · 2–4 mAs · 40" SID
- Best shows
- Anterior or posterior displacement of metacarpal fractures; foreign bodies
Image criteria
- Metacarpals superimposed; distal radius and ulna superimposed.
- Fan lateral: each phalanx seen separately, IP joints open.
- Thumb free of the other digits.
Technique values are typical starting points; follow your department's technique chart.
Labeled diagrams
Quick check
2. A PA hand such as this one is usually performed on the tabletop without a grid. What is the MAIN reason?
3. On a PA oblique hand, the midshafts of the third through fifth metacarpals overlap. What positioning error caused this?
4. A skier fell with the thumb caught in the ski pole strap and now has pain on the ulnar side of the thumb's MCP joint. Gamekeeper's (skier's) thumb is an injury of which structure?
5. On a PA oblique hand, the interphalangeal joints of the fingers appear closed and the phalanges look foreshortened. What is the MOST likely cause?
