Grashey View X-Ray: Shoulder Positioning, Anatomy, Normal Findings & Grashey vs AP Comparison

Content:

• What is Grashey View X-Ray?
• Shoulder Positioning
• Anatomy
• Normal Findings
• Grashey vs AP Comparison

What is Grashey View X-Ray?

The Grashey view X-ray is a specialized shoulder radiographic projection designed to provide a true anteroposterior (AP) image of the glenohumeral joint. Unlike the standard AP shoulder view, the Grashey view aligns the X-ray beam parallel to the joint space by rotating the patient’s body. This positioning allows a clear and unobstructed visualization of the joint space between the humeral head and the glenoid fossa.

This view is particularly useful in evaluating joint space narrowing, osteoarthritis, fractures, and subtle dislocations. It is commonly ordered in patients with chronic shoulder pain, suspected arthritis, or trauma. Because it eliminates overlapping of bony structures seen in a standard AP view, the Grashey projection provides a more accurate assessment of joint alignment and cartilage space.

Shoulder Positioning

Proper positioning is critical to obtain an accurate Grashey view. The patient is rotated approximately 35–45 degrees toward the affected side, depending on body habitus. This rotation aligns the scapula parallel to the imaging cassette. The X-ray beam is directed perpendicular to the glenohumeral joint space.

The arm is typically kept in a neutral position or slight external rotation. Incorrect positioning can cause overlap of the humeral head and glenoid, reducing diagnostic accuracy. Radiologic technologists carefully adjust rotation until the anterior and posterior rims of the glenoid are superimposed, confirming a true AP projection of the joint.

Anatomy

The Grashey view clearly demonstrates the glenohumeral joint, including the humeral head, glenoid cavity, and joint space. It also shows the greater and lesser tuberosities of the humerus, as well as part of the scapular body. Because of the optimized angle, the articular surfaces are visualized without distortion.

This view is especially helpful in assessing joint congruency and cartilage spacing. Subtle abnormalities such as marginal osteophytes, sclerosis, or small fractures of the glenoid rim can be more easily detected compared to a standard AP view. It provides a direct look at how the humeral head articulates with the glenoid fossa.

Normal Findings

In a normal Grashey view, the glenohumeral joint space appears symmetrical and well-maintained. The humeral head should be centered within the glenoid cavity, with no evidence of subluxation or displacement. The anterior and posterior glenoid rims should overlap, indicating correct positioning.

There should be no visible joint space narrowing, fractures, or irregular bone contours. The articular surfaces appear smooth, and there should be no signs of degenerative changes such as osteophyte formation or subchondral sclerosis. A normal Grashey view confirms proper joint alignment and healthy cartilage spacing.

Grashey vs AP Comparison

The primary difference between the Grashey view and the standard AP shoulder view lies in patient rotation and visualization of the joint space. In a regular AP view, the scapula is not rotated, which often results in overlapping of the humeral head and glenoid, making it difficult to accurately assess joint space narrowing.

In contrast, the Grashey view rotates the patient so that the X-ray beam is parallel to the glenohumeral joint. This provides a true representation of the joint space and is more sensitive for detecting arthritis and subtle joint abnormalities. Therefore, while the AP view is useful for general assessment, the Grashey view is superior for evaluating glenohumeral joint alignment and cartilage integrity.