Elbow Imaging

Question 1

Elbow Exposure factors and rationale

Answer 1

55 kVp - high image contrast, large attentuation difference
100 mA - fine focus for image detail
0.04s- gives required mAs of 4 when using 100mA, appropriate image density
No grid - minimal scatter radiation

Question 2

Imaging techniques for elbow projections

Answer 2

AP Elbow:
- arm is fully extended and externally rotated until hand is supine
- wrist, elbow and shoulder lie in the same plane
- centre midway btw humeral epicondyles
- collimate proximal 1/3 radius and ulna, elbow joint, distal shaft of humerus 1/3

Lateral Elbow:
- elbow bent to 90 degrees, wrist rotated laterally
- centre over lateral humeral epicondyles
- collimate proximal 1/3 radius and ulna, elbow joint, distal shaft of humerus 1/3

External Oblique of Radius Head
- set up as AP elbow, externally rotate 20 degrees, ask patient to lean sideways to help
- radiolucent pad under medial side of forearm
- centre over middle of crease of the elbow
- collimate proximal 1/3 radius and ulna, elbow joint, distal shaft of humerus 1/3

Lateral Head of Radius
- only if patient can flex elbow
- start in lateral elbow
- pronate hand until palm touches IR (like PA forearm)
- angle 20-25 degrees cranially if patient cannot move forearm to distort image
- centre over lateral humeral epicondyle
- to visualise medial aspect of radial head, medial aspect in contact with IR

Axial Elbow Projection
- used for supracondylar fractures
- centre between condyles over humerus
- arm bent towards body

Question 3

Radial Head Fracture

Answer 3

fracture in the radial head

Question 4

What projections for Radial Head Fracture? Explain rationale for each

Answer 4

**AP Elbow **- to identify any fracture lines, overview of elbow anatomy
**Lateral Elbow **- look for any anterior/posterior displacement and fat pad signs to indicate fracture
(Fat pad signs: indicate a fracture is present even if not visible)
**Radial head lateral **- able to see smaller/subtle fractures of radial head as it is free from superimposition
Radial Head oblique - able to see radial head more clearly

Question 5

Radiographic appearance of radial head fracture

Answer 5

• radial head is more visible
• possible fracture lines in the radial head
• posterior fat pad signs or elevated anterior fat pad signs

Question 6

Olecranon Fracture

Answer 6

fracture in the olecranon (tip of the elbow), creates a lot of soft tissues, more dark shadows on the image.

Question 7

What projections for Olecranon Fracture? Explain rationale for each

Answer 7

AP - to visualise elbow anatomy, where the fracture lines are, not best for olecranon due to superimposition but is a standard view
Lateral - see profile of olecranon, see displacement, angulation, posterior fat pad sign
**External Oblique (radial head view) **- to separate radial head from ulna, to see if any more fractures

Question 8

Radiographic appearance of olecranon fracture

Answer 8

• tip of the elbow is fractured off
• posterior fat pad signs
• dark shadows due to soft tissue swelling

Question 9

Supracondylar Fractures

Answer 9

fracture that occurs above the condyles, mainly in children (through epiphysis), sharp edges can damage soft tissues, very severe

Question 10

What projections for Supracondylar Fractures? Explain rationale for each

Answer 10

Horizontal beam AP - severe so likely wont be able to move, to visualise the elbow anatomy, shows alignment of humeral condyles
Horizontal beam Lateral - to assess displacement and angulation, fat pad signs

Question 11

Radiographic appearance of supracondylar fracture

Answer 11

• fracture through the epiphysis, above the condyles
• possible fat pad signs

Question 12

Elbow dislocation

Answer 12

when ulna and radius are displaced from their normal articulation with the distal humerus

Question 13

What projections for elbow dislocation? Explain rationale for each

Answer 13

Horizontal beam AP - severe so likely wont be able to move, to visualise the elbow anatomy, shows alignment of radius and ulna with the humerus
Horizontal beam Lateral - to assess displacement and angulation, fat pad signs

Question 14

Radiographic appearance of elbow dislocation

Answer 14

• radius and ulna no longer align with the distal humerus
• either posterior or anterior displacement
• fat pad signs

Question 15

Bony Tumours

Answer 15

bone is eaten away and swelling of soft tissue, narrow bridge of bone

Question 16

What projections for Bony Tumours? Explain rationale for each

Answer 16

AP - visualises anatomy of the distal humerus, proximal radius and ulna
Lateral - to see soft tissue swelling, bone density
External oblique of radial head - extra view to see how tumour affect the elbow

Question 17

Radiographic appearance of bony tumours

Answer 17

• soft tissue swelling
• dark shadows