Upper Limb 1

Question 1

Which direction is common for Glenohumeral Dislocation

Answer 1

Anterior (95%)

Question 2

Radiographic signs for Posterior GH Joint Dislocation

Answer 2

• Rim sign
• Trough line sign
• Lack of humeral head/glenoid fossa overlap
• Vacant glenoid sign
• Tennis racquet appearance
• Superior displacement of humeral head

Question 3

Mechanism of Inferior GH Dislocation

Answer 3

Hyperabduction and get stuck in abduction

Question 4

Radiographic sign in Rotator Cuff Tear

Answer 4

• Superior Subluxation of humeral head (not dislocation)
• Reduced Acromiohumeral Joint space (<7mm)
• Head may form pseudo joint superiorly with clavicle and acromion

Question 5

Reasons of humeral move superiorly when rotator cuff tear

Answer 5

Reduced holding power of infraspinatus tendon allowing elevation of humeral head by deltoid

Question 6

Mechanism of Glenoid Labrum Tear

Answer 6

Biceps tendon tesion during external rotation
Common in Overhead athletes

Internet:
Forceful eccentric traction is exerted on the biceps tendon and in throwers by the chronic stress placed on the labrum when the shoulder is forcefully abducted and externally rotated.

Question 7

Types of dislocated Acriomioclavicular Joint and its radiographic signs

Answer 7

Type I- No tear; no radiographic signs

Type II- AC ligaments torn; coracoclavicular ligaments stretched, but intact
Radiographic signs include increased AC joint space, but normal coracoclavicular distance

Type III- AC ligaments AND coracoclavicular ligaments torn
Radiographic signs include widened AC joint space, elevation of distal clavicle above acromion and coracoclavicular distance >5 mm wider than the opposite side

Question 8

Which direction of displacement is life-treatening for dislocated sternoclavicular joint

Answer 8

Posterior displacement
Damage the neurovascular bundle at thoracic outlet (subclavian artery and vein)

Extra:
anterior sternoclavicular and costoclavicular ligaments tear when the joint dislocated

Question 9

Common sites for Simple Bone Cyst (Unicameral Bone Cyst)

Answer 9

• Proximal femur and proximal humerus (60-75%)
• Fibula
• Base of calcaneal neck (4%, > 2 years of age)
• Talus
• Not in spine or calvarium

Question 10

Radiographic Signs of Simple Bone Cyst (Unicameral Bone Cyst)

Answer 10

• Intramedullary central metaphyseal lesion adjacent to epiphyseal cartilage (during active phase)
• Migrates into diaphysis with growth (during latent phase)
• Does not cross epiphyseal plate
• 2-3cm oval radiolucency with long axis parallel to long axis of host bone
• Thin sclerotic margin
• Fallen fragment sign if fractured (20%) = centrally dislodged fragment falls into a dependent position
• Most spontaneously regress

Question 11

General Tumour characteristics, commandments and clues

Answer 11

• Focal or multifocal areas of increased or decreased bone density
• Thou shall respect joint spaces and physes
• Soft tissue mass with bone involvement

Question 12

Bone Density Changes Tumour look-a-likes

Answer 12

• Epiphyseal changes
• Eccentric lesions with larger soft tissue components
• Eningmas, masqueradors

Question 13

What action of GH joint move when different location Fracture at proximal Shaft of humerus

Answer 13

Proximal to pec M
- Head abducts and rotates

Between pec M and delt
- head will adduct

Distal to deltoid
- head will abduct

Question 14

Radiographic signs for Anteior GH Joint Dislocation

Answer 14

• Inferomedial displacement of humeral head
• Altered head shape
• Presence of Hill-Sachs or Bankart lesions

Question 15

Causes and clinical finding for Posterior GH Joint Dislocation

Answer 15

Triple E:
Epileptic convulsion, electric shock or extreme trauma

Reverse hill-Sachs and reverse bankart lesion
- Impaction of the anteromedial humeral head and posterior glenoid