Shoulder Imaging

• The routine radiographic examination of the shoulder is AP IR and ER.
• If a fracture or dislocation is suspected, they will also take 1 AP view in neutral.
• The central ray in a AP ER is perpendicular to a point 1 inch below the coracoid process.
• What position is this?

  AP ER

  
• The central ray in AP IR is perpendicular to a point 1 inch below the coracoid process.
• What position is this?

  AP IR

  
• Routine radiographs of the acromoioclavicular joint are taken in an upright AP view, with and without weights.
• The central ray for an AC joint image is directed perpendicular to the midline of the body at the level of the AC joints.
• The scapular AP central ray is directed at the mid scapular area perpendicular to a point 2 inches below the coracoid process.
• The lateral scapular central ray is directed perpendicular to the mid lateral border of the scapula.
• The axillary view central ray is directed horizontally through the axilla toward the AC joint.
• The axillary view allows us to see the direction of shoulder displacement.
• Scapular lateral view is taken in the anterior oblique position. This is an essential special projection often used for the evaluation of a traumatized shoulder.
• CT scans of the shoulder are used for severe trauma. You can quickly assess alignment and displacement of fractures.
• CT of the shoulder may also be chosen to evaluate a labral or rotator cuff pathology if MRI is unavailable or contraindicated.
• If radiographs are normal, MRI is recommended for acute and subacute shoulder pain when RTC, instability, or labral tears are suspected.
• MRIs with contrast can indicate partial or complete tears in the shoulder.
• Normal MRIs with contrast should not have any contrast leakage into the subacromial space or muscle.
• MR Arthrography allows visualization of difficult structures through distention of the joint. They are most commonly done with labral tears.
• •When MRI is inconclusive, MR arthrography is a useful problem-solving tool to assess labral pathology
• The Quebec decision rule states that patients younger than 40 years only need pre and post-shoulder reduction film if the mechanism of injury involves a substantial force.
• In an AP ER, the greater tuberosity is in profile.
• In an AP IR, the lesser tuberosity is in profile.
• A lateral view of the scapula will evaluate the body of the scapula in profile.
• Proximal humerus fractures are typically caused by the FOOSH mechanism.
• Proximal humerus fractures are most common in elderly women with osteoporosis.
• Clavicle fractures are typically caused by the FOOSH mechanism or a fall directly onto the shoulder.
• Clavicle fractures are most common in the middle third.
• Clavicle fractures are best viewed on AP and 45 degree caudal tilt projections.
• GH dislocation is most commonly caused by forceful external rotation and extension while the arm is in abduction.
• The majority of GH dislocations are anterior and inferior
• Hill-sach's lesions are compression fractures of the humeral head in conjunction with GH dislocation.
• A Bankhart fracture is an avulsion fracture of the labrum from the rim of the glenoid.
• AC joint sprains are the result of downward force applied to the acromion process from either a fall on the point of the shoulder or a direct blow.
• AC joint sprains require the trauma imaging series if the injury is acute.
• Rotator Cuff tears are typically caused by acute traumatic events, FOOSH, or forceful abduction.
• RTC tears are most commonly seen in patients over the age of 50.
• Grade one labrum tears are an avulsion of the labrum off the rim. This is most common in acute trauma.
• Grade two glenoid tears are tears within the substance of the labrum. THis is most common in adults over 40.
• Grade three labral tears are also known as SLAP tears (superior labrum, anterior and posterior).