Humerus Shaft Anatomy and X-ray Positioning Quiz

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Questions and Answers

What is the position of the patient for the Antero-posterior – supine X-ray imaging of the humerus shaft?

Supine on the X-ray table (correct)

Prone on the X-ray table

Sitting with their back in contact with the cassette

Standing with their back in contact with the cassette

Where should the central ray be directed for the Lateral – erect X-ray imaging of the humerus shaft?

Right-angles to the shaft of the humerus (correct)

Midway between the shoulder and wrist joints

At an angle to the shaft of the humerus

Midway between the shoulder and elbow joints

How should the arm be positioned for Antero-posterior – supine X-ray imaging of the humerus shaft?

Abducted and partially flexed at the elbow joint

Slightly abducted and fully extended at the elbow joint (correct)

Adducted and fully flexed at the elbow joint

Adducted and fully extended at the elbow joint

What is the purpose of immobilizing the forearm using a sandbag for Antero-posterior – supine X-ray imaging of the humerus shaft?

To prevent movement during imaging Signup and view all the answers

What is essential for a successful image in Antero-posterior – erect X-ray imaging of the humerus shaft?

Both shoulder and elbow joints should be visible in the image Signup and view all the answers

In which clinical indication would a Lateral – erect X-ray imaging of the humerus shaft be necessary?

If a true lateral projection is needed to obtain an accurate image Signup and view all the answers

What is the recommended minimum SID for the AP projection—external rotation shoulder?

40 inches Signup and view all the answers

How should the patient be positioned for the AP projection—external rotation shoulder?

Erect or supine position Signup and view all the answers

Where should the CR be directed for the AP projection—external rotation shoulder?

1 inch inferior to coracoid process Signup and view all the answers

What is the purpose of externally rotating the arm in the AP projection—external rotation shoulder?

To visualize the greater tubercle in full profile on the lateral aspect of the proximal humerus Signup and view all the answers

What should be shielded during an AP projection—external rotation shoulder?

All radiosensitive tissues outside region of interest Signup and view all the answers

How should respiration be managed during an AP projection—external rotation shoulder?

Respiration should be suspended during exposure Signup and view all the answers

What is the purpose of the lateral projection for imaging the shoulder region?

To evaluate the glenohumeral joint space, head of the humerus, and scapula Signup and view all the answers

When is the AP projection taken with the patient lying supine on the trolley?

In cases of multiple trauma or immobility Signup and view all the answers

What does a lateral oblique ‘Y’ projection show when taken?

Recurrent dislocation Signup and view all the answers

Where does the lateral part of the clavicle articulate to form a joint?

With the acromion, forming the acromioclavicular joint Signup and view all the answers

What are the main parts of the scapula bone?

Acromion, glenoid cavity, and coracoid process Signup and view all the answers

What does Stryker’s projection demonstrate?

The glenoid cavity and joint space Signup and view all the answers

Study Notes

The text describes various X-ray projection techniques for imaging the shoulder region, including the lateral, antero-posterior (AP), and oblique projections.
The lateral projection is used to evaluate the glenohumeral joint space, the head of the humerus, the greater and lesser tuberosities, and the lateral aspect of the scapula. The patient stands with the affected shoulder against an erect cassette, the arm is abducted and rotated outwards, and the cassette is positioned to include the superior border of the scapula. The horizontal central ray is directed towards the medial border of the scapula and centred to the head of the humerus.
The AP projection is used to demonstrate the glenoid cavity and joint space when the body of the scapula is parallel to the cassette. In the erect position, the patient stands with the affected shoulder against the cassette and is rotated approximately 30 degrees to bring the plane of the glenoid fossa perpendicular to the cassette. The cassette is positioned so that its upper border is at least 5 cm above the shoulder. The horizontal central ray is centred to the palpable coracoid process of the scapula and collimated to an 18-24 cm cassette. The image should clearly show the joint space between the head of the humerus and the glenoid cavity, and the head, greater and lesser tuberosities, lateral aspect of the scapula, and the distal end of the clavicle.
In cases where the patient cannot be examined in the erect position due to multiple trauma or immobility, the AP projection is taken with the patient lying supine on the trolley. The upper border of the cassette is positioned at least 5 cm above the shoulder, and the vertical central ray is centred to the palpable coracoid process of the scapula. The subacromial space should be visible and the proximal end of the humerus, the lateral aspect of the scapula, and the whole of the clavicle need to be included.
A lateral oblique ‘Y’ projection is taken when the arm is immobilized and no abduction of the arm is possible. The patient stands or sits with the lateral aspect of the injured arm against an erect cassette, and the horizontal central ray is directed towards the medial border of the scapula and centred to the head of the humerus. This projection is used in recurrent dislocation, along with the antero-posterior with the humerus lateral, antero-posterior with the humerus oblique, and infero-superior projections.
The antero-posterior (modified) – Stryker’s projection is used to demonstrate a deformity of the humeral head. The patient lies supine on the X-ray table, and the arm of the affected side is extended fully and the elbow then flexed to allow the hand to rest on the patient’s head. The line joining the epicondyles of the humerus remains parallel to the tabletop, and the centre of the cassette is positioned 2.5 cm superior to the head of the humerus. The central ray is angled 10 degrees cranially and directed through the centre of the axilla to the head of the humerus and the centre of the cassette. This projection is used in the diagnosis of various shoulder conditions.
The text also mentions the simple anatomical structure of the shoulder region, including the clavicle, scapula, and humerus bones, and their respective joints. The lateral part of the clavicle articulates with the acromion, forming the acromioclavicular joint, while the medial third articulates with the sternum, forming the sternoclavicular joint. The scapula bone has a triangular shape and is located posterior to the chest wall. Its main parts include the acromion, glenoid cavity, and coracoid process. The humerus bone consists of the head, neck, greater tubercle, and lesser tubercle.

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Description

Test your knowledge of the anatomy and X-ray positioning for the shaft of the humerus. This quiz covers the structure of the humerus and the clinical indications and techniques for X-ray imaging of this area.