12.1 Upper Limb & Shoulder Girdle Positioning (Hand, Wrist, Forearm, Elbow, Humerus, Shoulder)

12.1 Upper Limb & Shoulder Girdle Positioning (Hand, Wrist, Forearm, Elbow, Humerus, Shoulder)

Hand Positioning & Radiographic Considerations

Radiographic examination of the hand requires detailed visualization of twenty-seven bones, including fourteen phalanges, five metacarpals, and eight carpal bones, along with their associated interphalangeal (IP), metacarpophalangeal (MCP), and carpometacarpal (CMC) joint spaces.

Standard Projections

1. PA Projection (Posterior-Anterior)

   • Patient & Part Position: Seat the patient at the end of the radiographic table with the elbow flexed 90 degrees. Place the palmar surface of the hand flat against the image receptor (IR), spreading the fingers slightly.
   • Central Ray (CR): Perpendicular to the third metacarpophalangeal (MCP) joint.
   • Diagnostic Criteria: Open interphalangeal and MCP joint spaces without rotation; symmetric concavities on both sides of the metacarpal shafts.

2. PA Oblique Projection

   • Patient & Part Position: From the flat PA position, rotate the entire hand and wrist 45 degrees laterally. Support the digits on a foam wedge or spread them parallel to the IR to prevent foreshortening.
   • Central Ray (CR): Perpendicular to the third MCP joint.
   • Diagnostic Criteria: Midshaft metacarpals free of superimposition; open 2nd and 3rd MCP joint spaces, with slight overlap of the 3rd, 4th, and 5th metacarpal heads.

3. Fan Lateral Projection

   • Patient & Part Position: Place the hand in a true lateral position with the ulnar surface resting on the IR. Fan the fingers out individually onto a radiolucent step wedge so each digit is clearly separated without overlap.
   • Central Ray (CR): Perpendicular to the second MCP joint.
   • Diagnostic Criteria: Individual phalanges demonstrated in true lateral profile without inter-digital superimposition; superimposed metacarpal shafts.

4. Norgaard Method ("Ball-Catcher's" View)

   • Clinical Indication: Specifically designed for early detection of rheumatoid arthritis (RA), demonstrating symmetry and subtle erosive changes at the 2nd through 5th MCP joint heads and base of phalanges.
   • Positioning: Place both hands supinated side-by-side. Medially rotate each hand 45 degrees into an AP oblique position, as if holding a ball.
   • Central Ray: Perpendicular to a midpoint between both hands at the level of the 4th MCP joints.

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Wrist Positioning & Special Scaphoid Views

The wrist consists of eight carpal bones arranged in proximal (scaphoid, lunate, triquetrum, pisiform) and distal (trapezium, trapezoid, capitate, hamate) rows. The scaphoid (navicular) is the most frequently fractured carpal bone.

Standard & Specialized Wrist Views

• PA Wrist: Hand pronated, fingers curled into a loose fist to bring the carpal bones into direct contact with the IR, reducing target-to-image distance (OID). CR directed perpendicular to the mid-carpal area (capitate).
• PA Oblique Wrist: Wrist rotated 45 degrees laterally from pronation. Demonstrates the trapezium and scaphoid free of major carpal overlap.
• True Lateral Wrist: Elbow flexed 90 degrees, wrist in true lateral position with ulnar surface on IR. The distal radius and ulna must be directly superimposed, demonstrating the palmar surface of the lunate in its normal concavity.

Specialized Scaphoid Projections

1. PA Wrist in Ulnar Deviation (Flexion)
   • Technique: Position wrist PA, then gently turn the hand laterally toward the ulnar side as far as patient tolerance allows without moving the forearm.
   • Rationale: Opens the interspaces between the adjacent carpals on the radial side and elongates the scaphoid, correcting native anatomical overlap.
2. Stecher Method
   • Technique: Place the wrist PA in ulnar deviation. Elevate the distal end of the IR 20 degrees on a sponge, OR leave the IR flat and angle the Central Ray 20 degrees proximally (toward the elbow) centered directly over the scaphoid.
   • Rationale: Places the long axis of the scaphoid perpendicular to the central ray, projecting it completely elongated without foreshortening.

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Forearm & Elbow Positioning

Forearm (AP & Lateral)

• AP Forearm: Patient seated, arm fully extended, hand supinated. Pronation causes the radius to cross over the ulna, creating artifactual superimposition. CR perpendicular to the midpoint of the forearm.
• Lateral Forearm: Elbow flexed 90 degrees, wrist in true lateral position with thumb pointing upward. Epicondyles of the humerus must be perpendicular to the IR.
• Image Scope: BOTH the wrist and elbow joints must be clearly included on a single radiograph on both AP and Lateral views.

Elbow Projections & Rotational Geometry

• AP Elbow: Arm fully extended, hand supinated. CR perpendicular to the mid-elbow joint (2 cm distal to interepicondylar line).
• AP Oblique - External (Lateral) Rotation: Rotate the entire arm laterally 45 degrees so epicondyles form a 45-degree angle to the IR.
  • Key Anatomical Marker: The radial head, neck, and tuberosity are projected completely free of superimposition by the proximal ulna.
• AP Oblique - Internal (Medial) Rotation: Rotate arm medially 45 degrees.
  • Key Anatomical Marker: The coronoid process of the ulna is demonstrated in profile, with the radial head and neck superimposed over the proximal ulna.
• True Lateral Elbow: Elbow flexed 90 degrees, wrist in lateral position.
  • Key Anatomical Marker: The olecranon process is visualized in profile within the olecranon fossa; elbow joint space is open and anterior/posterior fat pads are evaluated for occult joint effusion.

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Humerus & Shoulder Girdle Positioning

Humerus (AP vs. Lateral)

• AP Humerus: Patient erect or supine. Hand supinated, epicondyles parallel to the IR. Demonstrates the greater tubercle in profile laterally.
• Lateral Humerus: Epicondyles perpendicular to the IR (internal rotation of hand with palm against hip). Demonstrates the lesser tubercle in profile medially.
• Trauma Note: Never attempt to rotate an arm with a suspected humeral fracture; perform a transthoracic lateral projection instead.

Shoulder Girdle Projections

1. AP Shoulder - External Rotation
   • Epicondyles parallel to IR.
   • Anatomical Marker: Greater tubercle shown in full profile on the lateral aspect of the humeral head; humeral head in profile medially.
2. AP Shoulder - Internal Rotation
   • Epicondyles perpendicular to IR (back of hand against thigh).
   • Anatomical Marker: Lesser tubercle shown in profile pointing medially toward the glenoid cavity; greater tubercle superimposed over humeral head.
3. Scapular Y Projection (PA Oblique / AP Oblique for Shoulder Dislocation)
   • Patient Position: Patient rotated 45 to 60 degrees anterior oblique (for PA Y) with affected shoulder against IR, placing the body of the scapula perpendicular to the IR.
   • Anatomical Outcome: Scapular body, acromion, and coracoid form a distinctive "Y" shape.
   • Dislocation Assessment: In a normal shoulder, the humeral head is centered directly over the intersection of the Y. In an anterior dislocation, the humeral head lies beneath the coracoid process (inferior/medial to glenoid). In a posterior dislocation, the humeral head lies beneath the acromion process.
4. Grashey Method (AP Oblique Glenohumeral Joint)
   • Patient rotated 35 to 45 degrees toward the affected side.
   • CR perpendicular to the glenohumeral joint space.
   • Demonstrates an open glenohumeral joint space (glenoid cavity in profile) without superimposition of the humeral head.
5. Clavicle (AP & AP Axial)
   • AP Clavicle: CR perpendicular to mid-clavicle.
   • AP Axial Clavicle: CR angled 15 to 30 degrees cephalad (15-20 deg for hypersthenic, 25-30 deg for asthenic). Projects the clavicle above the scapula and ribs, clearing thoracic superimposition.

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Upper Extremity Positioning Summary Guide