Which type of shoulder dislocation is most common?

Which type of shoulder dislocation is most common?

• A. Posterior dislocation
• B. Inferior dislocation
• C. Superior dislocation
• D. Anterior dislocation

Answer: (D)

Most shoulder dislocations happen in the anterior direction because the humeral head is driven out of the glenoid forward when the arm is forced into abduction and external rotation. The anterior capsule is comparatively weaker, so this mechanism commonly pushes the head in front of the socket, making anterior dislocation by far the most frequent type—roughly the vast majority of acute dislocations. Posterior dislocations occur much less often and are classically linked to events that exert internal rotation and adduction, such as seizures or electric shocks; they’re also easy to miss on plain X-rays. Inferior dislocations (luxatio erecta) are rare and occur when the arm is forced overhead, with the head displaced downward. Superior dislocations are exceedingly uncommon because the shoulder’s anatomy and surrounding structures normally resist upward displacement. So the most common shoulder dislocation is the anterior type.

Most shoulder dislocations happen in the anterior direction because the humeral head is driven out of the glenoid forward when the arm is forced into abduction and external rotation. The anterior capsule is comparatively weaker, so this mechanism commonly pushes the head in front of the socket, making anterior dislocation by far the most frequent type—roughly the vast majority of acute dislocations.

Posterior dislocations occur much less often and are classically linked to events that exert internal rotation and adduction, such as seizures or electric shocks; they’re also easy to miss on plain X-rays. Inferior dislocations (luxatio erecta) are rare and occur when the arm is forced overhead, with the head displaced downward. Superior dislocations are exceedingly uncommon because the shoulder’s anatomy and surrounding structures normally resist upward displacement.

So the most common shoulder dislocation is the anterior type.