Procedures · ARRT Radiography
Hand, Wrist & Forearm Positioning for the ARRT Exam
27 bones, the carpal mnemonic, PIP and MCP centering points, scaphoid and ulnar deviation views, Gaynor-Hart carpal canal, and named fractures for the ARRT exam.
Overview
Hand, Wrist and Forearm covers 27 bones per side: 14 phalanges, 5 metacarpals and 8 carpals in two rows of four, memorized with the mnemonic Send Letter To Peter To Tell 'em Come Home. The scaphoid is the most frequently fractured carpal, which is why the wrist has an entire family of special scaphoid projections. Both ARRT projection lists name two of them, the PA with ulnar deviation and the PA axial (Stecher).
Fingers center at the PIP joint, the thumb at the first MCP joint, the PA and oblique hand at the third MCP, the fan lateral at the second MCP, the wrist at the midcarpal area, and the forearm at its midpoint with both joints on the image. The routine forearm is an AP with the palm up rather than a pronated PA, because pronation crosses the radius over the ulna near the upper third.
Four central ray angles carry the special views: 10 to 15 degrees proximally for the ulnar deviation scaphoid projection, 15 degrees for the modified Robert's method aimed at Bennett's fracture, 25 to 30 degrees for the Gaynor-Hart carpal canal, and 45 degrees for the carpal bridge. The deviation logic is one sentence: ulnar deviation opens the radial-side carpals, radial deviation opens the ulnar side.
Each named injury has a fixed site, and some also a set direction of displacement. A Colles fracture is a distal radius fracture displaced posteriorly, Smith's is its anterior reverse, a boxer's fracture crosses a metacarpal neck, most often the fifth, and skier's thumb is a sprained or torn ulnar collateral ligament imaged with the Folio stress method. The Norgaard ball-catcher view hunts early rheumatoid arthritis at the MCP and PIP joints, with both hands compared on a single exposure.
What you’ll learn in this chapter
The 20 study slides and 13 quiz questions in this chapter break down as follows. 3 chapters are free in full with a free account. The others come with a paid plan, and paid plans open soon.
Procedures
- Hand, Wrist & Forearm
Hand anatomy
- Phalanges and Metacarpals
Joints
- Every Joint, Named and Classified
- Quiz
Carpals
- The Eight Carpal Bones
- Quiz
Wrist anatomy
- The Wrist Joint, Canal and Fat Stripes
Forearm anatomy
- Radius and Ulna
Technique
- Technical Factors for the Upper Limb
Digits
- Fingers, Digits 2 to 5
Thumb
- The Thumb Routine
- Modified Robert's, Lewis and Folio
- Quiz
Hand
- The Hand Routine
- Lateral Alternates and the Ball-Catcher
- Quiz
Wrist
- The Wrist Routine
Scaphoid
- Scaphoid, Ulnar and Radial Deviation
- Quiz
Carpal canal
- Gaynor-Hart and the Carpal Bridge
- Quiz
Forearm
- The Forearm
- Quiz
Image critique
- Critiquing a Hand or Wrist Image
Clinical indications
- Named Fractures and Pathology
Exam traps
- Hand and Wrist Questions, Answered
- Quiz
Recap
- What to Carry Out of This Chapter
- Quiz
- Quiz
- Quiz
- Quiz
- Quiz
Key terms in this chapter
These are 8 key terms from this chapter. Use them as a flashcard pre-quiz.
- Scaphoid
- The largest bone of the proximal carpal row and the most frequently fractured carpal. Located 2 cm distal and medial to the radial styloid process.
- Carpal Sulcus
- The concave palmar surface of the carpals, also called the carpal tunnel, carrying the median nerve and tendons. Imaged tangentially with the Gaynor-Hart method.
- Ulnar Deviation
- Bending the wrist toward the ulnar side, which opens the radial-side carpals: scaphoid, trapezium and trapezoid. Commonly called the scaphoid projection.
- Modified Robert's Method
- An AP axial thumb projection with the CR angled 15 degrees proximally to the first CMC joint, used to rule out a Bennett's fracture.
- Gaynor-Hart Method
- The tangential carpal canal projection: wrist hyperextended, CR angled 25 to 30 degrees to the long axis of the hand, showing the pisiform and hamulus in profile.
- Norgaard Method
- The ball-catcher's position, both hands supinated and rotated 45 degrees on one exposure, used to find early rheumatoid arthritis at the MCP and PIP joints.
- Colles Fracture
- A transverse fracture of the distal radius with posterior displacement of the distal fragment. An ulnar styloid fracture accompanies it in 50 to 60 percent of cases.
- Bennett's Fracture
- A fracture of the base of the first metacarpal extending into the CMC joint, with subluxation and some posterior displacement.
Sample practice question: Extremity
One free sample question from the Extremity subcategory, like those in its 377-question bank. Several chapters share each sample, so it may not match this chapter's topic. See the format, the rationale style, and the difficulty before you sign up.
A patient presents with wrist pain after falling on an outstretched hand. The PA, lateral, and oblique wrist projections appear normal but clinical suspicion for scaphoid fracture remains. What additional projection should be performed?
Show answer and rationale
A, Incorrect: The carpal tunnel projection demonstrates the carpal tunnel itself.
B, Correct: Correct. ARRT and Merrill's call the Stecher method a PA axial scaphoid projection, while Bontrager titles its modified version a PA scaphoid. Both books raise the hand end 20° with a perpendicular CR, and Bontrager adds ulnar deviation. Merrill's also gives a variation with the CR 20° toward the elbow, and Bontrager gives a separate ulnar-deviation method with the CR angled 10° to 15° proximally. Use your program's text. Bontrager notes nondisplaced fractures may still need more projections or CT.
C, Incorrect: This is a real wrist projection, but it shows the medial carpals, not the scaphoid.
D, Incorrect: This is not a scaphoid projection. Radial deviation is its own PA wrist projection, and it shows the medial carpals.
Hands-on
Practice the positioning
Open the Positioning Lab to drill body position, central ray, anatomy, and common errors for each projection in this chapter.
- Thumb AP Seated, hand internally rotated so the dorsal thumb surface lies flat on the IR. SID 40".
- Thumb PA Oblique Seated, hand pronated, thumb obliqued 45 degrees. SID 40".
- Thumb Lateral Seated, hand turned slightly medially so the lateral surface of the thumb is on the IR. SID 40".
- Digits 2-5 PA Seated, hand pronated, palm down on IR. SID 40".
- Digits 2-5 PA Oblique Seated, hand rotated 45 degrees laterally, radial side raised. The 2nd digit may instead be a 45-degree medial oblique, thumb side down. SID 40".
- Digits 2-5 Lateral Seated, affected digit in true lateral with adjacent fingers flexed away. SID 40".
- Hand PA Seated with forearm on table, palm down. SID 40".
- Hand PA Oblique Seated with hand obliqued 45 degrees, radial side raised. SID 40".
- Hand Lateral Seated with medial side of hand on IR. SID 40".
- Wrist PA Seated with forearm on table, wrist pronated. SID 40".
- Wrist PA Oblique Seated with wrist rotated 45 degrees, radial side raised. SID 40".
- Wrist Lateral Seated, arm and forearm on the table, wrist lateral. SID 40".
- Wrist PA in Ulnar Deviation Seated, forearm extended on IR, hand deviated toward ulnar side. SID 40".
- Wrist PA Axial for Scaphoid Seated, hand in ulnar deviation. CR angled 10-15° toward elbow.
- Wrist Tangential (Carpal Canal) Seated, wrist hyperextended. CR angled 25–30° to long axis of hand.
- Forearm AP Seated, forearm extended on IR, palm supinated. SID 40".
- Forearm Lateral Seated, forearm lateral on IR with thumb up. SID 40".
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Frequently asked questions
What does the Hand, Wrist & Forearm Positioning for the ARRT Exam chapter cover?
Hand, Wrist and Forearm covers 27 bones per side: 14 phalanges, 5 metacarpals and 8 carpals in two rows of four, memorized with the mnemonic Send Letter To Peter To Tell 'em Come Home. The scaphoid is the most frequently fractured carpal, which is why the wrist has an entire family of special scaphoid projections. Both ARRT projection lists name two of them, the PA with ulnar deviation and the PA axial (Stecher).
How many study slides are in the Hand, Wrist & Forearm Positioning for the ARRT Exam chapter?
This chapter has 20 study slides and 13 quiz questions across 18 sections. The full chapter comes with a paid plan, and paid plans open soon. The free tier includes 3 complete chapters.
Is this chapter aligned with the current ARRT Content Specifications?
Every chapter on this site is mapped to the ARRT Radiography Content Specifications, but our line-by-line check against ARRT's outline isn't finished, so keep ARRT's outline beside it. Nothing here follows your exam date, so check which version applies to you. This chapter falls under the Procedures domain of the official ARRT exam blueprint.