MSK Imaging

Question 1

How do we read a shoulder XR?

Answer 1

Humeral head shape and position
- Is the head below the coracoid process? If yes - usually an anterior dislocation (?)

Acromioclavicular joint alignment
- Obvious displacement?

Coraco-claviular distance <14mm clavicular dislocation

Bony outlines
- Any cortical disruption (can you draw a clean line around it?) to the humeral head or neck, glenoid (articulates with humeral head) ?

Check two views

• Anterior +
• Apical oblique (good for showing gleno-humeral articulation) or Axial

Question 2

What findings might you expect on an anterior dislocation of the shoulder?

Answer 2

Increased distance in glenohumeral joint space
- Apical view very helpful

Small splinter-like fractures of bone from the glenoid

Question 3

How do we read a hand XR?

Answer 3

Soft tissue swelling

Question 4

What findings might you expect in rheumatoid arthritis in the hands?

Answer 4

LOSE: (for all joints affected)
Loss of joint space

Osteopaenia (periarticular)

Soft tissue swelling

Erosions - little chunks/’bites’ out of smooth edge of bones

ALSO:

• predilection for MCP and PIP joints
• Sparing of DIP (more in OA)
• Ulnar deviation and subluxation of MCP
• Deformities e.g. swan neck

Question 5

What findings might you find in osteoarthritis?

Answer 5

Loss of joint space

Osteophyte formation
- Bones erode and try to heal but badly - growth is irregular and patchy at joint spaces

Subchondral sclerosis
- Bright white just under joint (but bones generally are very osteopaenic)

Subchondral cysts
- Lucent, round structures

Question 6

What is lipohaemarthrosis?

Answer 6

Blood and fat within the joint, secondary to an intra-articular fracture

XRs taken will form a fat:blood fluid level with gravity

Question 7

How do read a knee XR?

Answer 7

Lateral view:
Effusion?
- Increased density in suprapatella compartment?
- Can confirm with USS

Fat-fluid level?
- (Within the suprapatella compartment)

Condylar surfaces smooth?

Patella in a normal shape and position?

Any small fragments of bone?

AP view:
Intercondylar eminence, tibial spines (everything in the middle)?
- Fractures here can be really subtle

Tibial plateau?
- Should be smooth, no lucent lines

Patella
- Round, darker opacity, no lucent lines

Any small displacement of bones elsewhere?

Question 8

How do you interpret an elbow XR?

Answer 8

Any anterior and posterior fatpads?
- Any fat pad up against the distal posterior humerus (ANY dark area at all) = pathological, either fluid/effusion, or blood - from a fracture (as should be homogenous with soft tissues

Radial head smooth?
- Any breaks in continuity?

Radiocapitellar line normal?

• Line down radius and passing through trochlear and ulnar(?)
• If not passing, then a dislocation is here e.g. Monteggia fracture (radial head dislocation with ulnar shaft fracture)

Question 9

How do you assess hip fractures?

Answer 9

Pelvic ring contour?

Obturator foramina contour?
- Formed by superior and inferior pubic rami

Sacroiliac joints?

Pubic symphysis?

Question 10

How do you look for hip fracture?

Answer 10

Types of fractures:

• Femoral shaft
• Greater trochanter

Shentons line ?