Diagnostic Radiology: Musculoskeletal System

Question 1

Alignment of carpal bones

Answer 1

PA view:
Smooth outline of Proximal / Distal row of carpal bones

Lateral view:
Straight line from Radius to Lunate to Capitate

Question 2

Perilunate dislocation + Distal radial fracture

Answer 2

1. Disruption of alignment of carpal rows
2. Capitate not sitting in “cup” of lunate
3. Cortical break at distal radius

Question 3

Unilateral facet joint dislocation

Answer 3

Lateral view:

• Rotated facets
• Misalignment of anterior + posterior line (anterior + posterior longitudinal ligament)

AP view:

• Misalignment of spinous process
• Widening of interspinous space

Question 4

Cannot see C7 on lateral view of X-ray

Answer 4

Swimmer views: Lift up hand to allow X-ray penetrate

Need to clear spine before discharge —> need to see C7 T1 junction as well

Question 5

X-ray of pelvis

Answer 5

1. Shenton’s line
   - medial femoral neck to inferior of superior pubic ramus
2. Iliopectineal line
3. Ilioischial line

Question 6

Neck of femur fracture

Answer 6

1. Disruption of Shenton’s line

2. Increased sclerosis due to impaction

Question 7

Femoral neck fracture (Intracapsular)

Answer 7

• Subcapital most common (others: Transcervical, Intertrochanteric, Subtrochanteric)
• Non-displaced / Displaced

Complications:
- Displaced fractures —> compromised blood supply to femoral head —> Osteonecrosis / AVN
- Other factors:
—> ↑ in intracapsular pressure leading to ↓ venous return
—> ↓ arterial perfusion

Question 8

***Lisfranc fracture dislocation

Answer 8

Fractures at base of metatarsals + Dislocated from tarsal bones

Oblique lateral view
- unremarkable

AP view:
- lateral shift of metatarsals

Question 9

Enchondroma

Answer 9

1. Well-defined margin
2. Central lucency +/- Chondroid calcification within the lucency
3. Prone to pathological fracture

Question 10

Bone sclerosis

Answer 10

Sclerotic bone metastasis:
- patchy sclerosis mixed with lucency

Paget’s disease (disorder of bone modeling):

• sclerosis concentrated on one side
• thickening of cortex
• expansion of bone size

Question 11

Dislocation of shoulder

Answer 11

• Anterior dislocation of humerus (95% vs posterior 5%)
• associated with:
  1. **Bankart fracture: fracture of inferior glenoid margin
  2. **Hill-Sachs deformity: cortical impaction of superior posterior aspect of humerus (shown on X-ray of internal rotation of shoulder)

Question 12

Disc degeneration

Answer 12

• Hypodense disc (dehydrated) on T2-weighted

Question 13

MRI role in MSS imaging

Answer 13

1. Disc-based pathology

2. Paravertebral soft tissue

Question 14

MRI of Discitis

Answer 14

1. Destruction of vertebral body

2. Disc space: Enhancing with Central necrosis of disc space