Positioning and Routine Projections of the Hands, Fingers and Thumb

Question 1

Name the fingers of the hand.

Answer 1

D1- Thumb

D2- Index finger

D3- Middle finger

D4- Ring finger

D5- Little finger

Question 2

How many phalanges are there in each hand?

Answer 2

14 phalanges.

Question 3

How many metacarpals are in each hand?

Answer 3

5

Question 4

How many carpals are in each hand?

Answer 4

8

Question 5

What type of joint is an Interphalangeal joint IPJ?

Answer 5

Hinge joints

Question 6

What type of joint is a metacarpophalangeal joint MCPJ?

Answer 6

Condyloid joint - a rounded protuberance at the end of some bones, forming an articulation with another bone.

Question 7

What type of joint is a carp omega carpal joint CMC?

Answer 7

Saddle joint

Question 8

What type of joint is a intercarpal joint?

Answer 8

Gliding joints with little movement.

Question 9

List the equipment required for a hand X-Ray.

Answer 9

• High output X-ray tube
• Generator (with fine focus)
• Image recording system (DR,CR)
• Radiographic markers

-Foam Pads (for mobilisation and positioning)

Question 10

What is the Preparation for Radiography of Hands / Fingers /Thumbs?

Answer 10

• Remove jewellery from wrist and fingers (rings etc!).
• The patient is seated at the end of the table with their elbow, forearm and hand in the same horizontal plane as the image receptor.
• The patients’ legs should NOT be under the table.

Question 11

List the parameters for a hand / fingers / thumbs.

Answer 11

• SID Source to detector 100cm (varies based on tube specification & area of interest)
• FSS Fine Focus For a sharper image
• kVp 52 - 55 Dependent on equipment used
• mAs 2-4

Question 12

List the Clinical indications of the hand

Answer 12

• Trauma:
  ? # / dislocation / subluxation / FB
• Arthritis:
  ? osteoarthritis / rheumatoid arthritis etc.
• ? bone age
• ? Marfan’s syndrome - disorder of body’s connective tissues, a group of tissues that maintain structure of body and support internal organs e.g. incaved chest.

Question 13

What are the routine projections for hands?

Answer 13

The two most commonly used:

-Dorsi-palmar (DP) FLAT
(this is frequently referred to as a PA)

• Dorsi-palmar oblique (DP oblique) 45
  (this is frequently referred to as a PA oblique)

(!) Tip – Don’t get confused with the projections of the feet / toes (Dorsi-plantar)

Question 14

What are the 3 other supplementary projections?

Answer 14

• Lateral projection
• Palmar-dorsi
• Ball-catchers

Question 15

Explain the lateral hand projection.

Answer 15

Taken for major trauma - as it is good for demonstrating anterior/posterior displacement/angulation of fractures of the metacarpals. Also taken for ?CMCJ dislocation and ?FB

90 degrees on table

Question 16

Explain the palmar-dorsi projection.

Answer 16

Only taken if the patient cannot get their hand flat on the receptor. Palm facing up and back of hand down on the detector.

Question 17

Explain the ball-catchers projection.

Answer 17

Rarely done nowadays. This projection is used to demonstrate the MCP joints and used to be the 2nd projection for ?RA Rheumatoid Arthritis

Holding a ball position

Question 18

Explain a Dorsi-palmar (DP) projection.

Answer 18

• Flex the elbow ≈ 90°and pronate the hand (palm down) on the image receptor.

-Fingers should be slightly separated.

• Centre the VCR (vertical) perpendicularly to the Head of the 3rd metacarpal.

Question 19

List the Dorsi-palmar image criteria.

Answer 19

• The entire hand should be seen without rotation.
  (Look for concavities on both sides of the shafts metacarpals)
• Phalanges should all be present with no overlapping of bone or soft tissue.
• MCP and IP joints should be visible. (This requires the hand to be flat on the receptor).

-The distal radius and ulna should be visible with no rotation.

Question 20

Explain the Doris-palmar oblique projection.

Answer 20

• From the prone position oblique the hand towards the lateral to form a 45°angle with the imaging receptor
• A radiolucent foam pad can be used to support the hand.
• Centre the VCR perpendicularly to the head of the 3rd metacarpal

Question 21

List the Dorsi-palmar oblique image criteria.

Answer 21

• The entire hand should be seen with the fingers well separated and the IPJs demonstrated.
• The metacarpals should be demonstrated with minimal overlapping of the shafts, bases + heads.
• No overlap = insufficient obliquity, Excessive overlap = too much obliquity.
• The MCP joints should be demonstrated.
• The distal radius and ulna should be demonstrated with some superimposition

Question 22

Explain the lateral hand projection.

Answer 22

Positioning:

• Hand is positioned in the lateral position with the radial and ulnar styloid processes superimposed.
• The thumb should be uppermost and parallel with the film.
• Centre the VCR perpendicularly to the 2nd MCPJ.

Question 23

Explain the ball-catchers view.

Answer 23

• Both hands are exposed together side by side.
• Patient is asked to imagine they are holding a large beach ball.
• Centre the VCR midway between the hands at the level of the 5th MCPJs.
• Usually for RA to view joints.