Hand Anatomy Quiz

Hand Anatomy

• 27 Bones: Each hand has 27 bones:
  • Phalanges (Fingers & Thumb): 14
  • Metacarpals (Palm): 5
  • Carpals (Wrist): 8

Phalanges: Fingers & Thumb

• Digits: Each finger and thumb is a digit.
• Phalanges: Each digit has 2 or 3 phalanges (bones):
  • Proximal: Closest to the palm
  • Middle: Middle bone in fingers 2-5
  • Distal: Farthest from the palm
  • Thumb: Has only proximal & distal phalanges

Metacarpals

• Palm: Form the palm of the hand.
• Numbered 1-5: Corresponds to digits.
• 3 Parts:
  • Head: Distal end that connects to phalanges.
  • Body: Curved middle part.
  • Base: Proximal end that connects to carpals.

Carpals

• Wrist: Form the wrist bones .
• 8 Total: Each wrist has 8 carpals, each with a specific name.

Joints

• Interphalangeal (IP) Joint: Between phalanges.
• Metacarpophalangeal (MCP) Joint: Between phalanges and metacarpals.
• Carpometacarpal (CMC) Joint: Between metacarpals and carpals.

General Positioning Considerations

• Sideways: Patient seated sideways at the end of the table.
• Shoulder Height: Table height should be near shoulder height for support.
• SID (Source to Image Distance): 40 inches.

Trauma Patients

• Stretcher: X-rays can be done on a stretcher.

Pediatric Patients

• Motion: Immobilization is key for children.
• Sponges & Tape: Use sponges and tape to help.
• Parents: Involve parents for assistance.
• Child Language: Speak clearly and in a language a child can understand.

Geriatric Patients

• Clear Instructions: Provide clear and complete instructions.
• Strenuous Positions: Patients may have difficulty holding strenuous positions.
• Reduce Techniques: Reduce technique due to potential osteoporosis.

Exposure Factors

• kVp: 60-80 kVp (lower to medium).
• Short Exposure Time: To minimize motion blur.
• Small Focal Spot: For sharper images.
• Soft Tissue Margins & Trabecular Markings: Images should show these details.
• Grids: Not used unless the body part is greater than 10 cm.

Collimation, Positioning & Markers

• Collimation: Collimate down to the area of interest.
• IR Size: Use the smallest IR size possible.
• Long Axis: Align the long axis of the part being imaged parallel to the long axis of the IR.
• Markers: Use correct markers on each image.

Clinical Indications

• Dislocation: Displacement of a bone from its joint.
• Fractures: Broken bones.
  • Bennett's Fracture: Fracture of the base of the first metacarpal.
  • Boxer's Fracture: Transverse fracture of the metacarpal neck.
  • Skier's Thumb: Sprain or tear of the thumb ligament.
• Osteoarthritis: Degenerative joint disease.
• Rheumatoid Arthritis: Chronic inflammatory disease affecting connective tissues.
• Osteoporosis: Reduced bone density.
• Foreign Objects: Presence of foreign objects in the hand.

Positioning: 1st Digit (Thumb)

• Routine Views: AP, PA Oblique, Lateral.

AP Projection - 1st Digit

• SID: 40 inches.
• Grid: No grid.
• IR: Smallest IR available.
• Position: Arm extended and thumb aligned with the IR.
• CR: 1st MCP joint.

PA Projection - 1st Digit

• Alternate View: When AP is not possible.
• SID: 40 inches.
• Position: Hand in near-lateral position, thumb resting on a sponge support block.
• CR: 1st MCP joint.

PA Oblique Projection - 1st Digit

• SID: 40 inches.
• Grid: No grid.
• IR: Smallest IR size available.
• Position: Thumb abducted slightly and resting on the IR.
• CR: 1st MCP joint.

Lateral Projection - 1st Digit

• SID: 40 inches.
• Grid: No grid.
• IR: Smallest IR size available.
• Position: Hand pronated and thumb abducted, then rotated into a true lateral position.
• CR: 1st MCP joint.

Positioning: Fingers 2-5

• Routine Views: PA, PA Oblique, Lateral.

PA Projection - Fingers 2-5

• SID: 40 inches.
• Grid: No grid.
• IR: Smallest IR available.
• Position: Hand pronated, fingers extended, affected finger aligned with IR long axis.
• CR: PIP joint.

PA Oblique Projection - Fingers 2-5

• SID: 40 inches.
• Grid: No grid.
• Position:
  • Fingers 3-5: Rotate hand laterally 45 degrees.
  • Finger 2: Rotate hand medially 45 degrees.
• CR: PIP joint

Lateral Projection - Fingers 2-5

• SID: 40 inches.
• Grid: No grid.
• Position: Hand in lateral position (thumb up) for fingers 3-5. Hand rotated medially (thumb down) for finger 2.
• CR: PIP joint

Positioning: Hand

• Routine Views: PA, PA Oblique, Lateral “Fan”.

PA Projection - Hand

• SID: 40 inches.
• Grid: No grid.
• Position: Hand pronated, fingers slightly spread.
• CR: 3rd MCP joint.

PA Oblique Projection - Hand

• SID: 40 inches.
• Grid: No grid.
• Position: Rotate hand laterally 45 degrees, fingers parallel to IR.
• CR: 3rd MCP joint.

Radial Deviation

• Less common than ulnar deviation
• Best for visualizing the hamate, pisiform, triquetrum, and lunate bones

Common Wrist Fractures

• Barton: fracture and dislocation of the posterior lip of the distal radius involving the wrist joint.
• Colles: transverse fracture of the distal radius with the distal fragment displaced posteriorly.
• Smith: a reverse Colles fracture, transverse fracture of the distal radius with the distal fragment displaced anteriorly.

Radiographic Positioning

• Patient's arm and shoulder should be on the same plane.
• Remove jewelry.
• Use 40 SID.
• Increase kVp for plaster casts: 5-7 kVp for small to medium; 8-10 kVp for large.
• Increase kVp for fiberglass casts: 3-4 kVp.

Routine Projections:

• PA
• Lateral
• Oblique

PA - Wrist

• Clinical Indications:
  • Fractures of the distal radius or ulna.
  • Isolated fractures of radial or ulnar styloid processes.
  • Fractures of individual carpal bones.
• 40 SID
• Align the long axis of the hand and wrist to the IR.
• Pronate the hand.
• Curl fingers to place wrist and carpal area in close contact with the IR.
• CR at the midcarpal area.

Alternative AP - Wrist

• Clinical Indications:
  • Fractures of the distal radius or ulna.
  • Isolated fractures of radial or ulnar styloid processes.
  • Fractures of individual carpal bones.
• 40 SID
• Align the long axis of the hand and wrist to the IR.
• Hand supinated, fingers curled to place wrist and carpals close to the IR.
• Best demonstrates intercarpal spaces and carpals.
• CR at the midcarpal area.

PA Oblique - Wrist

• Clinical Indications:
  • Fractures of the distal radius or ulna
  • Isolated fractures of radial or ulnar styloid processes
  • Fractures of individual carpal bones.
  • 40 SID
• Pronate the hand then rotate hand/ wrist laterally 45˚
• CR at the midcarpal area.

Distal Row Carpal Bones

• Trapezium: Located medial and distal to the scaphoid, proximal to the first metacarpal
• Trapezoid: Smallest bone in the distal row
• Capitate: Largest of all the carpal bones.

Lateral - Wrist

• 40 SID
• Hand and wrist placed in true lateral position (karate chop)
• CR – Midcarpal area
• Evaluation Criteria: the ulnar head should be superimposed over the distal radius, proximal second through fifth metacarpals should be superimposed.

Scaphoid Projections

• CR angle with ulnar deviation
• Modified Stecher Method
• Radial Deviation
• Gaynor Hart

PA and PA Axial Scaphoid – With Ulnar Deviation- Wrist

• Clinical Indication: Possible scaphoid fracture
• 40 SID
• Position for a PA wrist
• Without moving forearm gently evert hand toward ulnar side as far as patient can tolerate.
• PA – CR @ scaphoid (3/4 in distal and medial to radial styloid process)
• PA Axial – CR angled 10-15˚ proximally (toward elbow), directed at scaphoid

Evaluation Criteria – PA Axial Scaphoid

• Scaphoid clearly seen without superimposition
• Scaphoid not foreshortened

PA Scaphoid – Hand elevated and ulnar deviation (Modified Stecher Method)

• Clinical Indication: Possible scaphoid fracture
• 40 SID
• Place hand and wrist palm down on IR with hand elevated on a 20˚ sponge.
• Ensure wrist is in direct contact with IR.
• Gently evert or turn hand outward (toward ulnar side)
• CR perpendicular to IR and directed to the scaphoid.

PA Projection - Radial Deviation - Wrist

• Clinical Indications: possible fractures of the carpals on the ulnar side (lunate, triquetrum, pisiform, and hamate)
• 40 SID
• Position for a PA wrist.
• Gently invert hand toward thumb side.
• CR perpendicular to IR, directed to the midcarpal area.

Carpal Canal (tunnel) Tangential, Inferosuperior Projection (Gaynor Hart Method)

• Clinical Indications: Rule out abnormal calcification & bony changes in the carpal sulcus that may impinge on the median nerve, as with carpal tunnel syndrome. Possible fractures of the hamulus process of the hamate, pisiform, and trapezium.
• 40 SID
• Ask patient to hyperextend wrist (dorsiflex) as far as possible.
• Internally rotate the hand & wrist 10 degrees.
• CR angled 25-30˚ proximally, directed to 1in distal to base of third metacarpal (center of palm).

Evaluation Criteria – Gaynor Hart

• Carpals are demonstrated in a tunnel-like, arched arrangement
• Pisiform and hamulus process should be separated and visible

Forearm Anatomy

• Styloid process: Located on both distal ends of the radius and ulna.
• Ulnar notch: Small depression on the medial aspect of the distal radius.
• Head of Ulna: Located on the distal end of the ulna, fits in the ulnar notch to form the distal radioulnar joint.
• Radius: Body (shaft)
• Ulna: Body (shaft)
• Radius: Head, Neck, Radial tuberosity
• Ulna: Olecranon process, Coronoid tubercle, Trochlear notch (semilunar notch), Radial notch

Forearm Rotational Movements

• The forearm is routinely positioned AP with the hand supinated.

Test your knowledge on the anatomy of the hand, including the bones of the fingers, palm, and wrist. This quiz covers the 27 bones that make up each hand and the structure and function of the joints. Challenge yourself to recall the names and functions of the phalanges, metacarpals, and carpals.