Shoulder

Question 1

Shoulder projections

Answer 1

• AP
• Y view
• Axial (armpit view)
• apical oblique (45/45)

Question 2

AP positioning

Answer 2

• Scapula is parallel to the detector, affected arm is abducted and externally rotated
• No grid
• 2.5cm inferior of coracoid process
• Make sure to include base of scapula, lateral end of clavicle, and proximal 1/3 of
  humerus
• 66kVp 5mAs
• greater tuberosity is seen on external rotation

Question 3

PA Y View Positioning

Answer 3

• anterior aspect of affected side faceing the detector, palm of hand on stomach
• patient is turned until scapula is perpendicular to detector (thumb AP)
• centre on medial border of scapula
• ensure base and anterior aspect of scapula are included
• 70kVp 5mAs

Question 4

Axial (armpit view) positioning

Answer 4

• patient sitting next to detector, affected arm is abducted and elbow placed on detector
• glenohumeral joint is in centre of detector (patient may need to lean)
• head tilted to unaffected side
• centre on glenohumeral joint, 5-15 degree angulation towards elbow
• include glenohumeral joint, proximal 1/3 humerus and skin margins
• 60kVp 4mAs
• looks like a golf tee

Question 5

Apical Oblique Positioning

Answer 5

• patient sitting with back against detectors, turned 45 degree to affected side
• 45 degree caudal tube angle
• centre 2.5cm inferior of coracoid process
• include proximal 1/3 of humerus, 1/2 clavicle, ensure entire humeral head is images, skin margins
• 66kVp 5mAs

Question 6

Fractures and dislocations

• (most common location?)
• (what can be associated with anterior dislocation?)
• (Where does the clavicle # in <20yo)

Answer 6

• commonly through neck of humerus and the greater tuberosity
• anterior dislocation can cause # of glenoid and humeral head
• clavicle fracture:
  - <20yo = middle 1/3 #
  - >20yo = lateral 1/3 #
• should always have post-reduction films to ensure correct reduction

Question 7

Anterior Discloation

Answer 7

ALWAYS LOOK FOR ASSOCIATED GLENOID AND HUMERAL HEAD #

• humeral head will lie inferiorly of corocoid on the AP view
• axial show humeral head anterior of glenoid
• y view shows humeral head displaced anteriorly

HILL-SACHS DEFORMITY: compression # of posterolateral aspect of humeral head
BANKART’S LESION: # of anterior lip of glenoid

Haemorrhage in joint can cause inferior displacement but no anterior displacement: not a dislocation

Question 8

Posterior Dislocation

• (common or uncommon?)
• (appearance on AP?)
• (appearance on y and axial views?)

Answer 8

• uncommon, caused by excessive muscle spasms, e.g. convulsions or electrick shock
• AP image shows humeral head as symmetrical (lightbulb) due to INTERNAL ROTATION
• y view shows humeral head displaced posteriorly
• axial view shows humeral head displaced posteriorly of glenoid

Question 9

Acromioclavicular Injury

• (what image do you assess AC joint on?
• (what distance is suspicious?)
• (what should be in line if AC is normal?)

Answer 9

• only assess on AP image
• 8mm or more is suspicious
• inferior aspect of acromion and clavice should align, if there is a step there may be a subluxation

Question 10

AP Humerus Positioning

Answer 10

• patient’s back against the detector
• arm is abducted and midly externally rotated
• centre midshaft
• collimate to include skin margins, glenohumeral joint and elbow joint
• 66kVp 4mAs

Question 11

Lateral Humerus Positioning

Answer 11

• patient hand on stomach, facing detector
• patient turned until arm, shoulder and elbow are touching detector
• centre midshaft
• collimate to include all skin margins, glenohumeral joint and elbow joint
• 70kVp 6mAs