Shoulder Positioning Flashcards
What is the kvp used for shoulder imaging?
75-85
When is a grid used for a shoulder?
If anatomy is measuring over 10cm
T/F
Children and asthenic patients may require exposure factor adjustments without the use of grids
True
They may measure less than 10cm
What kv is required for AC joint projections?
Around 65-70
Because they are usually less than 10cm and do not require a grid
What projections is the AEC not recommended for?
-inferosuperior
-PA oblique
-AP oblique (grashey)
-lateral scapula
-clavicle
-AC joints
Why is a short exposure time used for most shoulder projection?
To reduce motion
What technical factors are used for an AP scapula? Why?
Low mA/high time
High exposure time to move anatomy away from scapula when patient is breathing
Why is a small focal spot used?
For increased detail
What SID is used for all shoulder projections?
What is the exception?
102-110cm
AC joints done at 180cm if done bilaterally
What 3 bones make up the shoulder girdle?
Humerus, scapula, clavicle
What is the joint called where the clavicle articulates with the manubrium of the sternum?
Sternoclavicular joint
What is the joint called where the clavicle articulates with the acromion?
Acromioclavicular joint
What shoulder projections are considered trauma?
AP neutral
PA oblique - transcapular Y
*Inferior-superior
What shoulder projections are considered non trauma?
AP internal/external
AP oblique -Grashey?
Superior inferior
Inferosuperior
For a trauma case, the hand is left in a neutral position. If the hand is in a neutral position, how will the epicondyles be situated in relation to the IR?
45 degrees to IR
Where is the CR centres for an AP neutral projection?
Midscapularhumeral joint space
Approx. 2cm inferior and slightly lateral to the coracoid process
For an AP neutral projection, where will the tubercles be seen?
Greater tubercle and lesser tubercle will both be not in profile
In an AP external projection, where will the epicondyles be in relation to the IR?
Parallel to the IR
Where is the CR centres for an external/internal AP projection?
1 inch (2cm) inferior to coracoid process
In an AP projection with external rotation, where will the tubercles be situated?
Greater tubercle in profile laterally
Lesser tubercle anterior
In an AP projection with internal rotation, where will the epicondyles be in relation to the IR?
Perpendicular to IR
In an AP projection with internal rotation, where are the tubercles situated?
Greater tubercle anterior
Lesser tubercle in profile medially
T/F
In an AP oblique projection (grashey method) the patient is rotated toward their affected side
True
What is the grashey method used for?
To visualize the glenoid cavity
How is the patient positioned for an AP oblique grashey projection?
35-45 degrees posterior oblique position
(Taken as a AP oblique)
Scapula should be placed parallel to IR
What anatomy is included in the collimated field for a AP oblique grashey projection?
Glenoid fossa, numeral head, coracoid, acromion, distal clavicle
Which part of the scapula form the “Y” in the PA oblique projection (scapular Y lateral)
Acromion and coracoid
What is the PA oblique should projection (scapular y) particularly useful to diagnose?
Shoulder dislocations
T/F
For a PA oblique scapular Y projection, the mid coronal plane should be placed at 45-60 degrees (anterior oblique position)
True
Where is the CR centered for a PA oblique scapular Y?
Directed at the medial border of the scapula, halfway between the inferior scapular and criminal angles
What angulation is used for the tangential supraspinatus outlet projection (neer)?
10-15 degrees caudad
*same position as PA oblique scapular Y
What can the inferosuperior axial projection demonstrate?
Dislocation
Fractures
Arthritic changes
Hills Sach defect
For an inferosuperior projection, where is the lesser tubercle presented?
In profile anteriorly
What CR angle should be for an inferosuperior axial projection?
25-35 degree medial to axilla
*angle depends on abduction of the humerus, less abduction = lesser angle
For the superoinferior projection, what angle is used, and what is the direction of the angle?
5-15 degrees through the shoulder joint towards the elbow
Greater angle when the patient cannot extend the shoulder over the IR
What are the 3 borders of the scapula?
Lateral (axillary)
Medial (vertebral)
Superior
What are the 3 angles of the scapula?
Superior
Inferior
Lateral
What projections are taken for the scapula?
AP projection
Scapular Y lateral
T/F
Slight Rotation of the shoulder to come in contact with the IR is not used for an AP scapula projection because it would result in greater superimposition of the rib cage
True
T/F
The curve of the clavicle is more pronounced on males than females
True
T/F
The mid clavicle lies at the same transverse level as the superior scapular angle
True
What are the essential projections for the clavicle?
AP
AP axial
Where is the CR centered for a clavicle projection?
Perpendicular to mid shaft of clavicle
What angulation is used for an AP axial clavicle?
15-30 degrees cephalic
Is more or less angle needed for thinner (asthenic) patients on an axial clavicle?
More angle
Is more or less angle needed for thicker (hypersthenic) patients for an axial clavicle?
Less angle
Why is respiration suspended at the end of inhalation for a clavicle?
To help elevate the clavicle
For alternative PA axial projections of the clavicle, what CR angulation is used?
15-30 degrees caudal to the supraclavicular fossa and midshaft of the clavicle
Why is an upright position required for AC joints instead of supine?
Supine position will reduce dislocation/separation
