Which type of shoulder dislocation is most common- posterior, inferior, anterior? Which x-ray views can you obtain to help you differentiate among these types?
Anterior is by far the most common dislocation type. [1]
| Anterior (95%) | Posterior (4%) | Inferior (1%) (aka luxatio erecta) | |
| Mech of injury | Direct blow while shoulder abducted/extended/ext rotated (e.g. playing basketball) | Electrical shock, seizures, significant direct blow | Direct blow to hyperabducted arm |
| Associated findings | Hill-Sachs, Bankart’s | Humeral fracture, reverse Hill-Sachs | Axillary nerve injury, rotate cuff tears |
| Presenting shoulder position | Slightly abducted/ext rotated | Adducted/int rotated | Hyperabducted/hand above head |
Multiple x-ray views may be taken in the setting of trauma:
- Anterior-Posterior (internal / external rotation)
[2]
- Scapular “Y” / Lateral View
[3]
“Y” formed by spine/coracoid/body of scapula
- Axillary view
[4]
This is obtained by:
[5]
** Great review of shoulder anatomy here: https://www.youtube.com/watch?v=xDePRKeB4kc
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Sources:
1. Mallia AK, Schraga ED. Shoulder Dislocation Joint Reduction. Medscape Oct 2014.
2. https://www.med-ed.virginia.edu/courses/rad/ext/3shoulder/01anatomy.html
3. http://www.radtechonduty.com/2012/04/scapular-y-lateral-anterior-oblique.html
4. http://uwmsk.org/RadAnat/AxillaryLabelled.html
5. http://faculty.washington.edu/alexbert/Shoulder/X-Rays.htm
