Shoulder dislocation
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Shoulder Dislocation Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Shoulder dislocation On the Web |
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American Roentgen Ray Society Images of Shoulder dislocation |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Jumana Nagarwala, M.D., Senior Staff Physician, Department of Emergency Medicine, Henry Ford Hospital; Cafer Zorkun, M.D., Ph.D. [2]
Overview
Diagnosis
X Ray
- Posterior dislocation may be missed initially on frontal radiographs in 50% of cases.
- Signs on frontal radiographs are subtle, including the trough line sign and the loss of normal "half-moon overlap".
- Axillary, scapular Y, or posterior oblique projections are needed for confirmation.
- The absence of external rotation on images in a standard shoulder series is a clue to posterior dislocation.
- Loss of half-moon overlap: On a normal true anteroposterior image, there is a half-moon overlap between the humeral head and the glenoid. In a posteriorly dislocated shoulder, there is lateral displacement of the humeral head with respect to the glenoid (losing the half-moon overlap)
- Trough line sign: In posterior dislocation, the anterior aspect of the humeral head becomes impacted against the posterior glenoid rim. With sufficient force, this causes a compression fracture on the anterior aspect of the humeral head. This compression fracture is analogous to the Hill-Sachs compression fracture seen with anterior dislocation of the glenohumeral joint. Frontal radiographs reveal two nearly parallel lines in the superomedial aspect of the humeral head.
- Shown below are the X ray findings of posterior shoulder dislocation.
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Courtesy: RadsWiki, copyleft source
- Shown below are the X ray findings of anterior shoulder dislocation.
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Courtesy: RadsWiki, copyleft source
- Shown below are the X ray findings of anterior shoulder dislocation post reduction.
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Courtesy: RadsWiki, copyleft source