Os acromiale - mesoacromion -symptomatic - MRI features

27 year old female patient with left shoulder pain. No history of trauma.

Coronal Oblique PDFS

Axial T1

MRI shows presence of os acromiale with hyperintense signal seen at the synchondrosis on the PDFS images indicative of edema which could be the cause of the pain.

There was no evidence of secondary rotator cuff impingement.

MRI shows presence of os acromiale with hyperintense signal seen at the synchondrosis on the STIR images indicative of edema which could be the cause of the pain.

Os acromiale:

• results from failure of an anterior acromial ossification center to fuse to the  acromial process

• caused by failure of one of three ossification centers; 

• ossification centers appear at age 15 and should fuse by age 22-25. 

• subtypes: (from anterior to posterior)

             -  preacromion, mesacromion, metacromion, and basiacromion types; 

              - mesacromion and metacromion are most common; 

• patients may show impingement like symptoms but will also have 

           localized tenderness.