Upper Extremities
Shoulder
Anatomy
Routine Projections (ARRT Required)
AP Shoulder – External Rotation
CR Location & Positioning
- SID: 40 inches (102 cm)
- Patient position: Upright preferred (or supine); thorax parallel to IR
- Adjustments: Abduct arm slightly; supinate hand so epicondyles are parallel to IR (true AP)
- CR: Perpendicular, 1 inch (2.5 cm) inferior to coracoid process
- Pt. Instructions: Suspend respiration; hold still
- Exposure: DR 70–80 kVp with grid (or 65–75 without); short time
Evaluation Criteria
- Coverage: Proximal humerus, superior scapula, lateral 2/3 clavicle; proximal 1/3 humerus included
- Rotation checks: Greater tubercle in profile laterally; humeral head in full profile; epicondyles parallel to IR
- Motion checks: Sharp cortical margins of tubercles and acromion
- Technique checks: Adequate penetration of humeral head and glenoid; soft tissue visible
- Clinical aim: Anatomic AP of humeral head; profile the greater tubercle
AP Shoulder – Internal Rotation
CR Location & Positioning
- SID: 40 inches (102 cm)
- Patient position: Upright or supine
- Adjustments: Flex elbow; place back of hand on hip; epicondyles perpendicular to IR
- CR: Perpendicular, 1 inch (2.5 cm) inferior to coracoid process
- Pt. Instructions: Suspend respiration; hold still
- Exposure: Same as external rotation
Evaluation Criteria
- Coverage: Same as external rotation
- Rotation checks: Lesser tubercle in profile medially; greater tubercle superimposed; epicondyles perpendicular
- Motion checks: Sharp lesser tubercle and glenoid rim
- Technique checks: Even exposure through humeral head and scapular body
- Clinical aim: True lateral of proximal humerus; profile the lesser tubercle
Scapular Y (PA Oblique Shoulder)
CR Location & Positioning
- SID: 40 inches (102 cm)
- Patient position: Upright preferred
- Adjustments: Rotate patient 45–60° PA oblique toward affected side; scapular body perpendicular to IR; arm neutral if trauma
- CR: Perpendicular to scapulohumeral joint (about 2–2.5 inches below top of shoulder)
- Pt. Instructions: Suspend respiration
- Exposure: 75–85 kVp with grid; short time
Evaluation Criteria
- Coverage: Entire scapula forming “Y,” proximal humerus, glenohumeral joint
- Rotation checks: Scapular body on-end with medial/lateral borders superimposed; humeral head centered over base of Y if not dislocated
- Motion checks: Crisp scapular borders and adjacent ribs
- Technique checks: Penetration to visualize scapular borders through thorax; no clipping of acromion or coracoid
- Clinical aim: Dislocation direction and alignment without moving the arm
Inferosuperior Axial Shoulder (Lawrence)
CR Location & Positioning
- SID: 40 inches (102 cm)
- Patient position: Supine; shoulder at table edge
- Adjustments: Abduct arm 90° if tolerated (minimum 20°); externally rotate hand; IR vertically against superior shoulder/neck; turn head away
- CR: 15–30° medially through axilla toward AC joint (greater abduction → greater angle)
- Pt. Instructions: Suspend respiration
- Exposure: 70–80 kVp; grid or air-gap; short time
Evaluation Criteria
- Coverage: Proximal humerus, glenoid, coracoid, acromion
- Rotation checks: Lesser tubercle in profile anteriorly; slight glenohumeral overlap; coracoid pointing anteriorly
- Motion checks: Sharp humeral head and glenoid rim
- Technique checks: Adequate penetration across joint; no burnout of humeral head
- Clinical aim: Glenohumeral relationship; assess tubercles and potential Hill-Sachs/Bankart
Transthoracic Lateral (Lawrence) – Trauma
CR Location & Positioning
- SID: 40 inches (102 cm)
- Patient position: Upright preferred (or supine); lateral to vertical grid
- Adjustments: Affected shoulder against IR; raise and elevate unaffected arm/shoulder to separate shoulders; midcoronal plane perpendicular; center IR at surgical neck; do not move injured arm
- CR: Perpendicular to surgical neck (angle 10–15° cephalad if unaffected shoulder cannot be elevated)
- Pt. Instructions: Full inspiration to improve contrast; or slow breathing technique (3–5 seconds) if immobilized
- Exposure: With grid; 75–85 kVp; low mA and long time if using breathing technique
Evaluation Criteria
- Coverage: Proximal humerus; scapula and clavicle through lung field
- Rotation checks: Scapula superimposed over thoracic spine; unaffected clavicle and humerus projected above the shoulder nearest IR
- Motion checks: With breathing technique, ribs/lungs blurred but humerus sharp
- Technique checks: Proper collimation (10 × 12); adequate penetration through thorax
- Clinical aim: Lateral of proximal humerus and GH alignment when abduction/rotation are not possible
Supplemental Projections
AP Neutral Rotation (Trauma Screening)
CR Location & Positioning
- SID: 40 inches (102 cm)
- Patient position: Upright or supine; thorax parallel to IR
- Adjustments: Arm in neutral position with palm resting against thigh; epicondyles at ~45° angle to IR
- CR: Perpendicular, 1 inch inferior to coracoid process
- Patient instructions: Suspend respiration
- Exposure: 70–80 kVp with grid
Evaluation Criteria
- Coverage: Proximal humerus and glenohumeral joint
- Rotation checks: Greater tubercle partially superimposed on humeral head; humeral head in partial profile
- Motion checks: Sharp bony and soft-tissue detail
- Technique checks: Uniform exposure through shoulder girdle
- Clinical aim: Trauma screening view when rotation or abduction is contraindicated
AP Oblique Glenoid (Grashey Method)
CR Location & Positioning
- SID: 40 inches (102 cm)
- Patient position: Upright or supine; posterior oblique toward affected side (35–45°)
- Adjustments: Rotate until scapular body is parallel to IR
- CR: Perpendicular, 2 inches medial and 2 inches inferior to superolateral border of shoulder
- Patient instructions: Suspend respiration
- Exposure: 75–85 kVp with grid
Evaluation Criteria
- Coverage: Glenoid cavity and proximal humerus
- Rotation checks: Open joint space between humeral head and glenoid; glenoid in profile
- Motion checks: Sharp cortical and trabecular margins
- Technique checks: Even exposure across joint and scapular body
- Clinical aim: Demonstrates articular surface of glenoid cavity; detects degenerative joint disease or labral injury
Inferosuperior Axial (Rafert Modification)
CR Location & Positioning
- SID: 40 inches (102 cm)
- Patient position: Supine; shoulder at table edge
- Adjustments: Arm abducted 90° if tolerated; hand externally rotated with thumb pointing down (45° oblique)
- CR: 15–30° medially through axilla toward AC joint
- Patient instructions: Suspend respiration
- Exposure: 70–80 kVp; grid or air-gap technique
Evaluation Criteria
- Coverage: Proximal humerus, glenoid, coracoid, and acromion
- Rotation checks: Lesser tubercle in profile anteriorly; humeral head and glenoid slightly overlapped
- Motion checks: Sharp bony margins; no motion blur
- Technique checks: Proper beam angle visualizing posterolateral humeral head
- Clinical aim: Evaluates Hill-Sachs lesion or anterior dislocation injuries
Inferosuperior Axial (West Point Method)
CR Location & Positioning
- SID: 40 inches (102 cm)
- Patient position: Prone; arm abducted 90°, head turned away from affected side
- Adjustments: IR vertical against superior shoulder; CR angled 25° anterior and 25° medial, entering 5 inches below and 1.5 inches medial to acromion
- Patient instructions: Suspend respiration
- Exposure: 75–85 kVp; grid
Evaluation Criteria
- Coverage: Glenoid rim and posterolateral humeral head
- Rotation checks: Glenoid rim free of overlap; humeral head projected inferiorly and medially
- Motion checks: Sharp trabecular pattern; no breathing motion
- Technique checks: Dual CR angle correctly visualizes anteroinferior glenoid
- Clinical aim: Demonstrates Hill-Sachs and bony Bankart lesions for chronic instability
Superoinferior Axial (Seated Alternative)
CR Location & Positioning
- SID: 40 inches (102 cm)
- Patient position: Seated at end of table; lean laterally over IR
- Adjustments: Elbow flexed 90°; hand pronated; epicondyles vertical
- CR: 5–15° through shoulder joint toward elbow
- Patient instructions: Suspend respiration
- Exposure: 70–80 kVp
Evaluation Criteria
- Coverage: Glenohumeral joint, proximal humerus, and AC articulation
- Rotation checks: Lesser tubercle in profile medially; joint space open
- Motion checks: No motion; crisp cortical margins
- Technique checks: Appropriate beam divergence avoiding distortio
- Clinical aim: Alternative to Lawrence for limited abduction; evaluates joint congruency
Neer Tangential Outlet Projection
CR Location & Positioning
- SID: 40 inches (102 cm)
- Patient position: RAO or LAO; scapula perpendicular to IR
- Adjustments: CR angled 10–15° caudad to superior humeral head
- Patient instructions: Suspend respiration
- Exposure: 75–85 kVp with grid
Evaluation Criteria
- Coverage: Humeral head projected below acromion and coracoacromial arch
- Rotation checks: Scapular Y evident; humeral head beneath AC joint
- Motion checks: Crisp scapular margins and outlet space
- Technique checks: No clipping of coracoid or acromio
- Clinical aim: Demonstrates outlet narrowing, impingement, or bony spurs
AP Axial Shoulder
CR Location & Positioning
- SID: 40 inches (102 cm)
- Patient position: Upright or supine; arm in neutral rotation
- Adjustments: CR angled 35° cephalad through scapulohumeral joint
- Patient instructions: Suspend respiration
- Exposure: 75–85 kVp
Evaluation Criteria
- Coverage: Glenoid cavity, humeral head, clavicle, and upper scapula
- Rotation checks: Clavicle projected above superior scapular border
- Motion checks: Sharp humeral and scapular margins
- Technique checks: Uniform density; no overpenetration
- Clinical aim: Identifies posterior dislocations and glenohumeral alignment
Shoulder Projection Error-Recognition Chart
Even small positioning deviations in shoulder imaging can significantly change how key structures appear.
The following chart summarizes frequent positioning and exposure errors seen in AP, oblique, and axial shoulder projections.
Use it as a quick diagnostic tool — identify what went wrong, interpret what it looks like on the image, and recall the precise correction or rationale for accurate repeat imaging.
| Projection | Common Error or Misadjustment | What You See on the Image | How to Fix It / Why It Happened |
|---|---|---|---|
| AP External Rotation | Arm not fully externally rotated | Greater tubercle partially superimposed on humeral head | Ensure hand is supinated and epicondyles parallel to IR; this isolates the greater tubercle in profile |
| AP Internal Rotation | Arm insufficiently rotated inward | Lesser tubercle not in profile; humeral head not rounded | Rotate arm until back of hand rests on hip and epicondyles are perpendicular to IR |
| AP Neutral Rotation | Hand position inconsistent | Variable overlap of greater tubercle and humeral head | Confirm palm rests on thigh, not supinated or pronated, to maintain neutral alignment |
| Grashey (AP Oblique) | Patient not rotated enough toward affected side | Joint space appears closed; glenoid not in profile | Increase body rotation to 35–45° toward affected side until scapula is parallel to IR |
| Grashey (AP Oblique) | Patient over-rotated | Glenoid cavity appears foreshortened or humeral head overlaps | Decrease rotation; check that scapular body is just parallel to IR |
| Scapular Y (Oblique) | Patient under-rotated | Scapular body not seen on end; Y distorted | Increase rotation until scapular borders superimpose |
| Scapular Y (Oblique) | Patient over-rotated | Scapular body over-superimposed on ribs | Reduce obliquity; the scapular lateral border should clear the ribs |
| Inferosuperior Axial (Lawrence) | Arm not abducted enough (< 20°) | Humerus superimposes shoulder; joint not open | Abduct arm ≥ 20° (ideally 90°) and maintain external rotation |
| Inferosuperior Axial (Lawrence) | CR not angled enough medially | Glenoid overlap or foreshortening | Adjust 15–30° medial angle through axilla toward AC joint |
| Transthoracic Lateral | Unaffected shoulder not raised | Overlap of humeri; poor separation | Elevate unaffected arm fully to clear the injured side |
| Transthoracic Lateral | No breathing technique used | Ribs sharply defined, humerus under-penetrated | Use low mA, long exposure (3–5 s) with slow breathing to blur ribs |
| Neer Tangential (Outlet) | CR not angled caudad | Outlet space closed; humeral head obscures AC joint | Angle 10–15° caudad to project under the acromion |
| AP Axial Projection | CR not angled cephalad enough | Clavicle not above scapula; dislocation hard to assess | Confirm 35° cephalad angle through scapulohumeral joint |
| West Point Axial | Incorrect dual angle | Glenoid rim not demonstrated; Hill-Sachs not visible | Use 25° anterior + 25° medial CR to project through glenoid cavity |
Hows & Whys of Shoulder Radiography
Anatomy
- What bones form the shoulder girdle?
The clavicle and scapula form the girdle, articulating anteriorly with the sternum and posteriorly joined to the humerus at the glenohumeral joint. - What type of joint is the glenohumeral articulation?
It is a diarthrodial, synovial ball-and-socket joint allowing movement in all directions. - What is the most frequently fractured part of the proximal humerus?
The surgical neck, because it lies distal to the joint capsule and is structurally narrower. - Which tubercle serves as attachment for each rotator-cuff tendon?
The greater tubercle receives the supraspinatus, infraspinatus, and teres minor tendons; the lesser tubercle receives the subscapularis tendon. - What anatomic landmarks create the “Y” in the scapular Y projection?
The acromion (posterior limb), coracoid process (anterior limb), and body of the scapula (stem). - Why is the glenoid cavity angled anteriorly about 35–40 degrees?
To permit humeral head articulation while maintaining clearance of the thorax during arm movement.
Positioning
- Why is the hand supinated for the AP external rotation?
Supination aligns the humeral epicondyles parallel to the IR, producing a true AP projection and showing the greater tubercle in profile. - Why is the hand placed on the hip for the AP internal rotation?
This turns the epicondyles perpendicular to the IR, giving a true lateral projection of the proximal humerus and demonstrating the lesser tubercle in profile. - Why is the neutral-rotation AP used for trauma?
It avoids manipulation of the injured limb while still allowing limited assessment of the humeral head orientation. - Why is the arm abducted 90 degrees for the inferosuperior axial (Lawrence)?
Abduction clears the acromion from the joint and allows the central ray to pass through the axilla to the glenohumeral articulation. - Why is the beam angled 15–30° medially for the inferosuperior axial?
The medial angle projects through the joint space and elongates the humeral head-to-glenoid relationship. - Why is the patient rotated 45–60° in a PA oblique for the scapular Y?
This degree of rotation brings the scapular body perpendicular to the IR so its borders superimpose, forming the “Y” reference for assessing dislocation. - Why is the unaffected shoulder raised for the transthoracic lateral?
Elevation separates the shoulders vertically, preventing overlap of the humeri through the thorax. - Why is full inspiration or a slow-breathing technique used for the transthoracic lateral?
Inspiration increases air contrast, and slow breathing blurs lung markings to better define the humerus. - Why is the scapula positioned perpendicular to the IR for the Neer outlet view?
This orientation allows the caudal-angled beam to project the coracoacromial arch tangentially, outlining the outlet space. - Why is the body rotated 35–45° toward the affected side for the Grashey projection?
That rotation makes the scapular body parallel to the IR, opening the glenohumeral joint space in profile. - Why is the beam angled 35° cephalad for the AP axial projection?
The cephalic angle projects the humeral head inferiorly relative to the glenoid, clarifying posterior dislocations.
Technique & Image Evaluation
- How can you tell the AP external rotation is true AP?
The greater tubercle appears in lateral profile and the humeral head is fully rounded, showing minimal glenoid overlap. - How can you tell the AP internal rotation is true lateral?
The lesser tubercle is clearly in profile medially and the greater tubercle is superimposed on the humeral head. - How can you verify the neutral-rotation AP?
The greater tubercle partially superimposes the humeral head, showing neither full AP nor full lateral appearance. - How can you confirm the scapular Y is positioned correctly?
The medial and lateral borders of the scapula are superimposed; the humeral head lies directly over the base of the Y if not dislocated. - How can you identify an anterior vs. posterior dislocation on the Y view?
Anterior dislocation places the humeral head beneath the coracoid; posterior dislocation places it beneath the acromion. - How can you verify the inferosuperior axial angle and abduction were correct?
The coracoid process points anteriorly, the lesser tubercle is in profile anteriorly, and the glenoid rim is just overlapping the humeral head. - How can you evaluate the transthoracic lateral for adequacy?
The humeral shaft and head are visible through the thorax with blurred rib outlines and sharp bony margins; scapula overlies the spine. - How can you verify correct exposure on shoulder projections?
Bony trabeculae are distinct within the humeral head and scapula, soft-tissue margins are visible, and no burnout occurs at the cortical edges. - How can you confirm proper collimation?
The field includes the proximal one-third of the humerus, the lateral clavicle, and the scapular body without clipping of the acromion or coracoid. - How can you detect motion?
Loss of cortical sharpness at the tubercles or acromion and blurred trabecular pattern indicate patient or breathing motion.
Clinical Applications
- When should a Grashey projection be added?
When joint-space narrowing or labral pathology is suspected to evaluate the articular cartilage of the glenoid cavity. - When is a Neer outlet projection performed?
To assess impingement by visualizing the coracoacromial arch and outlet for narrowing or spurs. - When should an inferosuperior Rafert or West Point view be chosen?
For recurrent anterior dislocation to evaluate Hill-Sachs defects and anteroinferior glenoid rim fractures. - When is a transthoracic lateral preferred?
When the patient cannot abduct or rotate the affected arm due to trauma or immobilization. - What projections together best demonstrate dislocation direction?
The scapular Y and an axillary (inferosuperior) projection provide orthogonal evaluation of humeral-head displacement.
