Elbow

Question 1

Radiocapitellar Line

Answer 1

Line running along the radius and radial head should pass through the capitellum. If not, the radial head is dislocated

This is ALWAYS true on a lateral elbow x-ray

This line can be affected by radiographic positioning

Question 2

NAME THIS PATHOLOGY:

of proximal 1/3 ulna with dislocation of the radial head

The radiocapitellar line is not straight

Answer 2

Monteggia #

Question 3

Anterior Humeral Line

Answer 3

Line down the anterior cortex of the humerus should have 1/3 of the capitellum anterior of it.

If less than 1/3, chances are high of a posteriorly displaced supracondylar #

This line is not useful in very young children when there is only partial ossification of the capitellum

Question 3

Fat Pads

Answer 3

ANTERIOR FAT PAD: always visible
- only indicative of a # if displaced away from the humerus

POSTERIOR FAT PAD: always abnormal if visible

Displacement of fat pads requires the arm put into a collar and cuff until orthopaedic assessment

Question 4

supracondylar #

Answer 4

most common elbow # in 4-8yo

can cause vascular damage, nerve damage, malunion or deformity

Question 5

Elbow Ossification

Answer 5

C - capitellum - 1 year
R - radial head - 3 years
I - internal epicondyle - 5 years
T - trochlea - 7 years
O - olecranon - 9 years
L - lateral epicondyle - 11 years

The trochlea always ossifies after the internal epicondyle.
If you see trochlea but no internal epicondyle, it could be an avulsed internal epicondyle

Question 6

AP Elbow Positioning

Answer 6

• Elbow abducted, extended and in supination (palm to ceiling)
• centre between humeral epicondyles
• include distal humerus and proximal radius & ulna
• 55kVp 4mAs

Question 7

Lateral Elbow Positioning

Answer 7

• Elbow abducted and flexed 90 degree
• Humeral epicondyles are superimposed
• Thumb points to the ceiling
• Centre over humeral epicondyles
• Include distal humerus and proximal radius & ulna
• wrist, elbow and shoulder all in the same plane

55kVp 5mAs

Question 8

AP Radius and Ulna Positioning

Answer 8

• affected arm abducted, extended and in supination on detector (dorsum of hand on detector)
• humeral epicondyles are equidistant from detector
• centre midshaft
• collimate to include lateral skin margins, elbow joint and proximal carpal bones
• 55kVp 3mAs

Question 9

Lateral Radius and Ulna Positioning

Answer 9

• affected arm is abducted and flexed 90 deg at elbow. Ulnar aspect of wrist in contact with detector, hand is perpendicular to detector.
• hand, elbow and shoulder should be in the same plane
• centre midshaft
• collimate to include elbow and proximal row of carpals, lateral skin margins
• 57kVp 3mAs