Finger, Hand, & Wrist Projections

Finger, Hand, & Wrist Projections

Overview

  • This document provides detailed guidelines for the radiographic positioning and evaluation criteria for imaging the fingers, hand, and wrist, specifically focusing on various projections.

Joints of the Hand

  • Interphalangeal (IP) Joint

    • Involves the hinge joints between the phalanges of the fingers.

  • Metacarpophalangeal (MCP) Joint

    • The joint between the metacarpal bones and the proximal phalanges.

  • Carpometacarpal (CMC) Joint

    • The joint where the metacarpal bones connect with the carpal bones.

Specific Joints

  • 1st MCP Joint - Joint at the base of the thumb.

  • 2nd to 5th MCP Joints - Joints for the other four fingers.

  • Trapezium - A carpal bone forming the CMC joint of the thumb.

  • Hamate and Capitate - Additional carpal bones.

PA Finger (2-5) Positioning

  • SID: 40 inches

  • Hand Position: Pronated with fingers separated

  • Central Ray (CR): Directed at the Proximal Interphalangeal (PIP) joint

Evaluation Criteria

  • Entire finger and distal metacarpal visible.

  • Long axis of finger aligned with long axis of image receptor (IR).

  • No rotation indicated by symmetric shaft concavities.

  • Fingers must be separated.

  • Open joint spaces visible.

Oblique Finger (2-5) Positioning

  • SID: 40 inches

  • Hand Position: Obliqued laterally by 45°, with optional second finger medial oblique.

  • CR: Directed at the PIP joint.

Evaluation Criteria

o- Entire finger and distal metacarpal visible.

  • Long axis of finger aligned with IR.

  • 45° obliquity achieved.

  • Fingers separated.

  • Open joint spaces clearly defined.

Lateral Finger (2-5) Positioning

  • SID: 40 inches

  • CR: Directed to PIP joint.

  • Hand Position: In a lateral position with finger extended.

Evaluation Criteria

  • Entire finger and distal metacarpal visible.

  • Long axis of finger aligned with IR.

  • True lateral position determined by concave anterior phalanx.

  • Open joint spaces identified.

AP Thumb Positioning

  • SID: 40 inches

  • CR: Directed to 1st MCP joint.

  • Hand Position: Rotate hand until the posterior surface of the thumb touches the IR.

  • Note: PA position not advisable due to increased Object-to-Image Distance (OID).

Evaluation Criteria

  • Whole thumb, first metacarpal, and trapezium must be visible.

  • Long axis of finger aligned with IR.

  • No rotation indicated by symmetric shaft concavities.

  • Open joint spaces visible.

Oblique Thumb Positioning

  • SID: 40 inches

  • Hand Position: Palmar surface rests on the IR.

  • CR: Directed to the 1st MCP joint.

Evaluation Criteria

  • Whole thumb, first metacarpal, and trapezium visible.

  • Long axis aligned with IR.

  • 45° obliquity achieved.

  • Open joint spaces clearly defined.

Lateral Thumb Positioning

  • SID: 40 inches

  • Hand Position: Prone hand is rotated medially until the thumb is in true lateral position.

  • CR: Directed to 1st MCP joint.

Evaluation Criteria

  • Whole thumb, whole first metacarpal, and trapezium visible.

  • Long axis aligned with IR.

  • True lateral position confirmed by concave anterior phalanx.

  • Open joint spaces visible.

PA Hand Positioning

  • SID: 40 inches

  • Hand Position: Pronated hand with CR directed to 3rd MCP joint.

Evaluation Criteria

  • Entire hand and wrist with 1 inch of distal forearm visible.

  • Long axis aligned with IR.

  • No rotation indicated by symmetric shaft concavities of digits 2-5.

  • Fingers must be separated.

  • Open joint spaces observed.

Oblique Hand Positioning

  • SID: 40 inches

  • Hand Position: Pronated hand laterally oblique by 45°.

  • CR: Directed to 3rd MCP joint.

Evaluation Criteria

  • Entire hand/wrist with 1 inch of distal forearm visible.

  • Long axis aligned with IR.

  • 45° obliquity indicated by distal heads of 3rd-5th metacarpals overlapping and no overlap of distal heads of 2nd & 3rd metacarpals.

  • Fingers separated.

  • Open joint spaces observed.

Hand-Fan Finger Lateral Positioning

  • SID: 40 inches

  • Hand Position: In true lateral position with thumb-side up and fingers spread.

  • CR: Directed to 2nd MCP joint.

Lateral Evaluation Criteria

  • Entire hand/wrist with 1 inch of distal forearm visible.

  • Fingers separated with the thumb in a slight oblique position.

  • Long axis aligned with IR.

  • True lateral position confirmed by distal radius and ulna superimposed and metacarpals superimposed.

  • Open joint spaces identified.

Optional Lateral Hand Positions

Lateral in Extension & Lateral in Flexion

  • Utilized for foreign bodies or displaced metacarpal fractures.

  • Note: Considerations for injury may dictate preferred positions.

Technical Considerations

Collimation

  • Must be four-sided to focus the exposure on the anatomy of interest.

Technical Factors

  • kVp Range: 50-60 kVp with low mAs

  • SID: 40 inches

  • Focal Spot Size: Small

  • Exposure Time: Short

  • Anatomic Side Marker: Must be included within the exposure field.

Joint Distortion Concern

  • Maintain alignment of digit and joint parallel to the IR.

  • Center CR to the anatomy of interest to reduce distortion.

PA Wrist Positioning

  • SID: 40 inches

  • Hand Position: Pronated with a slight arch in the hand to bring carpals close to the IR.

  • CR: Centered at midcarpal area.

PA Wrist Evaluation Criteria

  • Should include mid-metacarpals to distal radius/ulna.

  • Long axis of wrist aligned with the IR.

  • No rotation: Achieved by equal concavity of metacarpal shafts.

PA Oblique Wrist Positioning

  • SID: 40 inches

  • Hand Position: Pronated, laterally rotated by 45°.

  • CR: Directed to midcarpal area.

Oblique Wrist Evaluation Criteria

  • Entire wrist from mid-metacarpals to distal radius/ulna visible.

  • Long axis of wrist aligned with IR.

  • 45° Obliquity: Indicated by ulna partially superimposing the radius and proximal 3rd-5th metacarpal bases superimposed.

Lateral Wrist Positioning

  • SID: 40 inches

  • Hand Position: True lateral position for wrist.

  • CR: Directed to midcarpal area.

Lateral Wrist Evaluation Criteria

  • Entire wrist from mid-metacarpals to distal radius/ulna visible.

  • Long axis of wrist aligned with IR.

  • True lateral: Verified by head of ulna superimposed by distal radius and proximal 2nd-5th metacarpals superimposed.

Lateral Hand/Wrist Considerations

  • Assess rotational positioning of the hand and wrist:

    • Internally Rotated

    • Externally Rotated

Summary of Projections

  • PA, Oblique, and Lateral are the primary projections used for imaging the fingers, hand, and wrist, each with specific positioning techniques and evaluation criteria to ensure optimal visualization of the targeted anatomy.