What is the correct centering point for a PA hand projection?

The central ray should be directed perpendicular to the third metacarpophalangeal (MCP) joint. This location ensures both the wrist and distal phalanges are included in the collimated field.

Why is the PA projection preferred over the AP for hand radiography?

The PA projection places the dorsum of the hand closer to the image receptor, reducing geometric distortion and magnification. It also minimizes motion blur by allowing the patient to rest their palm flat on the IR surface.

When should you add a scaphoid view to a wrist series?

Add a scaphoid view whenever the patient reports anatomical snuffbox tenderness following a fall on an outstretched hand (FOOSH injury). Up to 16% of scaphoid fractures are not visible on standard wrist projections.

What elbow projection best demonstrates the radial head and neck?

The AP oblique elbow with lateral (external) rotation — rotating the arm 45° laterally moves the radius away from the ulna, making the radial head and neck visible free of superimposition.

How can you tell if a lateral elbow is correctly positioned?

In a true lateral elbow, the humeral epicondyles are superimposed (one directly on top of the other), the olecranon process is seen in profile, and the elbow is flexed to 90°.

Why is collimation particularly important for upper extremity radiography?

Upper extremity X-rays use tabletop technique without a grid. Without the scatter-reducing effect of a grid, tight collimation is the primary defense against fog and unnecessary patient dose. It also improves image contrast.

Radiography of the Upper Extremity: Hand, Wrist, Elbow Positioning Guide

Published June 15, 2026 by the Radiography 101 Clinical Team

PA radiograph of a normal hand demonstrating metacarpal and phalangeal anatomy — Normal PA hand radiograph. The hand is the most frequently imaged part of the upper extremity in emergency departments. Image: Sarah Cartwright, CC BY-SA 2.0, via Wikimedia Commons.

If you're a rad tech student or new technologist, you'll spend a significant portion of your clinical time imaging the upper extremity. Hand, wrist, and elbow X-rays are among the most common radiographic exams performed in emergency departments and outpatient clinics — accounting for a large share of every radiographer's daily workload.

Getting the positioning right the first time isn't just about image quality. It's about patient care — reducing repeat exposures, minimizing discomfort for injured patients, and producing diagnostic images that allow accurate interpretation.

This guide covers the standard projections for the hand, wrist, and elbow, with Clark's-specific centering points, technique guidelines, and the positioning pitfalls that trip up students on the ARRT exam. For other positioning guides, see our knee X-ray positioning guide and abdominal X-ray positioning. Upper extremity imaging is performed using general X-ray equipment — and for complex fractures, CT may be ordered for surgical planning.

Hand Projections

The hand is imaged using a three-view series: PA, PA oblique, and lateral. The PA projection is preferred over the AP because it places the hand closer to the image receptor (IR), reducing geometric distortion and magnification.

PA Hand

Parameter	Value
IR size	18 × 24 cm (8 × 10 in)
CR location	Perpendicular to the 3rd metacarpophalangeal (MCP) joint
SID	100 cm (40 in)
kVp	50–60
Evaluation criteria	Entire hand and wrist visible; MCP and IP joints open; symmetric concavity of metacarpal shafts; equal soft tissue on both sides of phalanges 2–5

Positioning: Seat the patient at the end of the table. Place the forearm and palm flat on the IR. The elbow, forearm, and hand should all be in the same horizontal plane — if the elbow is higher than the hand, the MCP joint spaces will close, mimicking pathology. Spread the fingers slightly and relax the hand.

🔬 Clinical Pearl: A common positioning error is hyperextending the fingers. This causes the IP joints to close and introduces beam angulation through the phalanges. Keep the digits naturally relaxed — a slight, natural curl is acceptable.

PA Oblique Hand

Parameter	Value
CR location	Perpendicular to the 3rd MCP joint
Obliquity	45° lateral rotation from pronated
Immobilization	45° radiolucent foam wedge under the elevated side

Positioning: From the PA position, rotate the patient's hand laterally (externally) until the MCP joints form approximately 45° with the IR. Support the extended fingers with a 45° foam wedge. The thumb and index finger may need additional elevation on a radiolucent pad to avoid foreshortening.

Evaluation check: At 45°, the midshafts of the 3rd, 4th, and 5th metacarpals should not overlap. If the distal heads overlap excessively, the hand is over-rotated. If there's too much separation between shafts, the rotation is insufficient.

Lateral Hand

Parameter	Value
CR location	Perpendicular to the 2nd MCP joint
Position	Ulnar aspect down on IR
Fan lateral	Digits placed on a radiolucent wedge to eliminate superimposition

Positioning: Place the ulnar aspect of the hand on the IR with the thumb at a right angle to the palm. For the fan lateral (preferred for foreign body localization), place the digits on a radiolucent sponge so they fan out, preventing superimposition of the phalanges.

Evaluation check: The distal radius and ulna should be superimposed, indicating a true lateral. The metacarpals should be stacked over one another. The thumb should be free of superimposition from the rest of the hand.

📋 ARRT Exam Tip: The ARRT frequently tests the centering point for the PA hand — always the 3rd MCP joint. For the lateral hand, the CR shifts to the 2nd MCP joint. Remember this distinction — it's a common trick question.

Wrist Projections

The standard wrist series includes PA, PA oblique, and lateral projections. A scaphoid view (with ulnar deviation) is added when scaphoid fracture is suspected.

PA Wrist

Parameter	Value
IR size	18 × 24 cm (8 × 10 in)
CR location	Perpendicular to the midcarpal area (at the level of the scaphoid)
SID	100 cm (40 in)
kVp	50–60

Positioning: Place the forearm parallel to the IR with the hand pronated. Have the patient slightly flex the digits and arch the hand so the wrist makes close contact with the IR surface. The elbow, forearm, and wrist should be at the same height.

Evaluation check: The proximal metacarpals should show equal concavity on both sides. The distal radius and ulnar styloid should be visible with minimal superimposition at the radioulnar joint.

PA Oblique Wrist

Parameter	Value
CR location	Perpendicular to the midcarpal area
Obliquity	45° lateral rotation from pronated
Use	Demonstrates the scaphoid, trapezium, and trapezoid free of superimposition

Positioning: From the PA position, rotate the patient's wrist laterally (externally) approximately 45°. Support the elevated side with a 45° foam wedge. The wrist should be slightly extended.

Lateral Wrist

Parameter	Value
CR location	Perpendicular to the radial styloid
Position	Forearm flat on table, wrist in true lateral

Positioning: From the lateral elbow position, adjust the wrist so it's in a true lateral. The forearm lies flat on the table. The CR enters at the radial styloid — the bony prominence on the thumb side of the wrist.

Evaluation check: The distal radius and ulna should be completely superimposed. The scaphoid, lunate, and capitate should be visible in profile.

Scaphoid View (Ulnar Deviation)

Parameter	Value
CR location	Perpendicular to the scaphoid
CR angulation	10° proximally (toward the elbow)
Hand position	Deviated ulnarward (toward the little finger side)

This dedicated view is essential because the scaphoid is the most commonly fractured carpal bone, and up to 16% of scaphoid fractures are missed on routine wrist views without ulnar deviation. The ulnar deviation elongates the scaphoid, bringing it into profile and away from overlying carpal bones.

💡 Clinical Pearl: When a patient presents with anatomical snuffbox tenderness and a negative routine wrist series, do not clear the wrist — add a scaphoid view. Scaphoid fractures have high rates of avascular necrosis (AVN) if missed, and the medicolegal implications are significant.

Elbow Projections

The standard elbow series includes AP, AP oblique (medial and lateral rotation), and lateral projections.

AP Elbow

Parameter	Value
IR size	18 × 24 cm (8 × 10 in)
CR location	Perpendicular to the elbow joint, midway between the humeral epicondyles
Position	Full extension, hand fully supinated

Positioning: With the patient seated, extend the arm fully so the elbow is at the same height as the shoulder. The hand should be fully supinated (palm up). The CR enters the joint midway between the medial and lateral epicondyles — approximately 2.5 cm distal to the line connecting them.

Evaluation check: The humeral epicondyles should be parallel to the IR. The joint space should be open and centered. The olecranon process should be seen within the olecranon fossa.

⚠️ Trauma note: If the patient cannot fully extend the elbow (possible fracture or dislocation), do not force extension. Use the AP with partial flexion — flex the elbow as much as the patient can tolerate and angle the CR through the forearm to the joint.

Lateral Elbow

Parameter	Value
CR location	Perpendicular to the elbow joint
Elbow flexion	90°
Epicondyles	Perpendicular to the IR

Positioning: Flex the elbow to exactly 90°. The humeral epicondyles should be perpendicular to the IR. The hand is in a lateral (thumb-up) position. The CR enters at the elbow joint — palpate the lateral epicondyle and center approximately 2.5 cm distal to it.

Evaluation check: The epicondyles should be superimposed (one on top of the other). The joint space should be open. The olecranon process should be visible in profile. A positive fat pad sign (a triangular lucency displacing the anterior or posterior fat pads) indicates an intra-articular fracture — frequently tested on the ARRT exam.

AP Oblique Elbow

Projection	Rotation	CR	Demonstrates
Medial (internal) rotation	45° medially	Perpendicular to elbow joint	Coronoid process of the ulna
Lateral (external) rotation	45° laterally	Perpendicular to elbow joint	Radial head and neck

Positioning for medial rotation: From the AP position, rotate the arm medially 45° (palm rotates toward the body). The medial epicondyle becomes more prominent.

Positioning for lateral rotation: From the AP position, rotate the arm laterally 45° (palm rotates away from the body). The radial head becomes visible free of ulnar superimposition.

📋 ARRT Exam Tip: Know which oblique view shows which structure — medial (internal) rotation = coronoid process, lateral (external) rotation = radial head. This is one of the most commonly tested positioning distinctions on the ARRT registry exam.

Upper Extremity Projection Summary

Body Part	Projection	CR Location	Key Positioning Point
Hand	PA	3rd MCP joint	Palm flat, fingers relaxed
Hand	PA Oblique	3rd MCP joint	45° lateral rotation
Hand	Lateral	2nd MCP joint	Fan lateral for all digits
Wrist	PA	Midcarpal area (scaphoid level)	Digits flexed, wrist in contact
Wrist	PA Oblique	Midcarpal area	45° lateral rotation
Wrist	Lateral	Radial styloid	Forearm flat, true lateral
Wrist	Scaphoid	Scaphoid	Ulnar deviation, 10° CR proximally
Elbow	AP	Midway between epicondyles	Full extension, hand supinated
Elbow	Lateral	Elbow joint	90° flexion, epicondyles superimposed
Elbow	AP Oblique Medial	Elbow joint	45° medial rotation (coronoid process)
Elbow	AP Oblique Lateral	Elbow joint	45° lateral rotation (radial head)

Common Positioning Errors

Hand

Elevated elbow — the most common error. When the elbow is higher than the hand, the wrist hyperextends and the MCP joints close. Solution: position the elbow and hand at the same height using pillows or foam pads.
Hyperextended fingers — causes closed IP joints. Keep digits naturally relaxed.

Wrist

Rotation on lateral wrist — the radius and ulna must be superimposed. Any rotation obscures the radiocarpal joint and makes evaluation of dislocation impossible.
Insufficient ulnar deviation for scaphoid — without full ulnar deviation, the scaphoid remains foreshortened and superimposed over adjacent carpal bones.

Elbow

Incorrect flexion angle on lateral — the elbow must be at exactly 90°. Less than 90° foreshortens the joint; more than 90° distorts the articular relationships.
Patient leaning — if the patient leans toward or away from the table, the elbow rotates out of true AP or lateral position. Watch the patient's torso alignment, not just the arm.

ARRT Exam Tips for Upper Extremity Positioning

PA hand centering = 3rd MCP joint — this is the single most tested upper extremity position fact on the registry.
Lateral elbow flexion = 90° — not 80°, not 100°.
Oblique elbow, medial rotation = coronoid process — lateral rotation = radial head.
Fan lateral hand = foreign body — the fan lateral eliminates phalangeal superimposition, making FB localization possible.
Scaphoid view uses ulnar deviation + 10° proximal CR angle — the only wrist view that requires CR angulation.
Grid use — grids are typically NOT needed for distal extremity work (kVp under 70). Use tabletop technique.
Collimation — collimate to the skin line on all four sides. Tight collimation reduces scatter and patient dose.
Immobilization — use sandbags over the distal forearm (never over the fracture site), tape for digits, and radiolucent sponges for oblique positioning.

🔬 Clinical Pearl: One positioning principle applies to all upper extremity radiography: the part being imaged must be parallel to the IR. This is the foundation of minimizing distortion. Check this in every projection — if the forearm is sloped, the joint spaces will be distorted regardless of how accurate the CR placement is.

About the Author — This guide was prepared by the Radiography 101 Clinical Team, a group of registered radiologic technologists and educators dedicated to helping students succeed on the ARRT exam and in clinical practice. Content is verified against Clark's Pocket Handbook for Radiographers (16th ed.) and current ARRT content specifications.