Chpt 4 - Forearm / Elbow

Question 1

What projection should you use if the patient cannot fully extend the elbow for an AP?

Answer 1

Alternate partial flexion

Question 2

How many projections does the alternate partial flexion position call for? What are they and where is the CR directed to?

Answer 2

humerus parallel to the IR
forearm parallel to the IR
CR directed to mid-elbow joint

Question 3

Where is the mid-elbow joint?

Answer 3

about 3/4 in distal to the midpoint of a line between the epicondyles

Question 4

What should you do if the patient can’t partially extend the elbow, and the elbow remains flexed near 90 degrees?

Answer 4

Use the alternate partial flexion with the two projections, but angle CR 10-15 degrees into the elbow joint

Question 5

What projection should you do if the patient’s elbow is flexed more than 90 degrees?

Answer 5

acute flexion projection

Question 6

For the acute flexion projection, what two projections are needed, and where is the CR directed for them?

Answer 6

distal humerus - CR perp. to IR and humerus, directed to midway between epicondyles
proximal forearm - CR perp. to forearm, directed to about 2 in proximal to the olecranon process

Question 7

the only difference among the four radial head - lateromedial projections of the elbow

Answer 7

the rotation of the hand and wrist

Question 8

the four radial head - lateromedial projections

Answer 8

all are lateral elbow
- max external rot. of hand
- hand lateral
- hand pronated
- max internal rot. of hand

Question 9

what best visualizes the radial head and neck of the radius and capitulum of the humerus

Answer 9

APO - Lateral (external) rotation of the elbow

Question 10

What best visualizes the coronoid process of the ulna and trochlea in profile?

Answer 10

APO - Medial (internal) rotation of the elbow

Question 11

the 3 concentric arcs

Answer 11

• trochlear sulcus
• trochlea notch
• outer ridges of capitulum and trochlea