Shoulder (Garth view)

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The apical oblique projection or the Garth view of the shoulder is the tangential projection of the shoulder used in trauma .

Indications

The view is best for evaluating the glenohumeral joint for dislocations and trauma to the glenoid of the scapula; this projection can be used as a replacement to the lateral scapula view in trauma, however, interpretation is difficult. The angle of the beam means it is tangential to the anterior-inferior glenoid rim (great for Bankart fractures) and gives a better view of the posterior humeral head (ideal for Hill-Sachs lesion) .

Patient position

  • the patient is preferably erect, best placed on a seat sitting against the upright bucky (due to the angle of the tube) 
  • the midcoronal plane of the patient is parallel to the image receptor, in other words, the patient's back is against the image receptor
  • the glenohumeral joint of the affected side is at the center of the image receptor
  • the patient is turned toward the affected side to show the glenohumeral joint space; this is achieved by rotating the patient 30-45°
  • if possible the patient has the affected side's hand resting on the unaffected shoulder 

Technical factors

  • axial oblique projection
  • centering point
    • 45° caudal angle of the x-ray tube
    • 2.5 cm inferior to the coracoid process, or 2 cm inferior to the lateral clavicle at the level of the glenohumeral joint
  • collimation
    • superior to the skin margins
    • inferior to include one-third of the proximal humerus
    • lateral to include the lateral portion of the humeral head often the skin margins (dependent on body habitus) 
    • medial to 1/3 of the medial clavicle
  • orientation  
    • portrait
  • detector size
    • 18 cm x 24 cm
  • exposure
    • 60-70 kVp
    • 10-18 mAs
  • SID
    • 100 cm
  • grid
    • yes (this can vary departmentally)

Image technical evaluation

  • the humeral head will appear elongated (due to angle) 
  • the coracoid process is sometimes projected over the humeral head 
  • the AC joint should be superior to the humeral head 
  • posterior dislocation
    • the humeral head will be projected superior to the glenoid often obstructed by the acromion
  • anterior dislocation
    • in the majority of cases, the humeral head will be projected inferior to the glenoid 

Practical points

Due to the steep angle of the tube, it is advisable to have the patient sitting on a stool for the examination, otherwise, you may hit the ceiling with your x-ray tube.

Use of the AEC is not advisable; best to set your own exposures based off the AP shoulder.