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