The Veil of Obscuration: Additional Radiographic Sign of Posterior Shoulder Dislocation

Area of Science:

• Radiology
• Orthopedic Surgery
• Trauma Imaging

Background:

• Posterior glenohumeral joint dislocations are challenging to diagnose radiographically.
• Classic radiographic signs exist but may not always be present or definitive.

Purpose of the Study:

• To introduce and describe the "veil of obscuration" radiographic sign.
• To determine the incidence and validity of this sign in posterior shoulder dislocations.
• To compare it with established radiographic indicators.

Main Methods:

• Retrospective review of 30 acute posterior shoulder dislocation cases.
• Radiographic analysis by two musculoskeletal radiologists for the "veil of obscuration" and other signs.
• Statistical analysis of sign incidence, associated factors (fractures, surgery, injury mechanism).

Main Results:

• The "veil of obscuration" was identified in 40% of posterior shoulder dislocations.
• Reverse Hill-Sachs lesion (83%) and fixed internal rotation (76%) were more common.
• This sign was associated with seizures and surgical cases, unlike the trough line seen in major trauma.

Conclusions:

• The "veil of obscuration" is a newly described radiographic sign for posterior shoulder dislocations.
• Its incidence is comparable to other classic signs.
• It may assist in the diagnosis of posterior glenohumeral joint injuries.