Hi Maria,

check these links.

http://www.biomedcentral.com/1741-7015/9/8

http://www.ncbi.nlm.nih.gov/pubmed/20605555

Hi Maria,

Check these articles and search also their related articles...

http://www.medscape.com/viewarticle/747395_2

BMC Musculoskeletal Disorders

High Prevalence of Shoulder Girdle Muscles With Myofascial Trigger Points in Patients With Shoulder Pain

Carel Bron, Jan Dommerholt, Boudewijn Stegenga, Michel Wensing, Rob AB OostendorpDisclosures

BMC Musculoskelet Disord. 2011;12

http://link.springer.com/article/10.1186%2F1471-2474-10-92

BMC Musculoskeletal Disorders

July 2009, 10:92,

Open Access

Date: 24 Jul 2009

Contributions of myofascial pain in diagnosis and treatment of shoulder pain. A randomized control trial

Sara Perez-Palomares, Bárbara Oliván-Blázquez, Ana Mª Arnal-Burró, Orlando Mayoral-Del Moral, Elena Gaspar-Calvo, Mª Luisa de-la-Torre-Beldarraín, Elena López-Lapeña, Marina Pérez-Benito, Victoria Ara-Loriente, Laura Romo-Calvo

You can also check the related articles in this review.

http://www.ncbi.nlm.nih.gov/pubmed/25603748

no sorry Maria no expertise in this

There seems to be a contradiction in your question. Subacromial syndrome, or impingement syndrome, should imply subacromial pain, that is, pain generated between the acromion and the head of the humerus. That area has a bursa, tendons, a labrum, a joint capsule,sometimes AC joint bone spurs, and the glenohumeral joint, but no muscles. So pain generated in that spot does not constitute "myofascial pain." One has to examine well to determine whether there is pain being generated from the subacromial spacen itself. 

Myofascial pain is generated in muscles. Trigger points into spots of myofascial pain will do absolutely nothing to relieve pain coming from the subacromial space. 

And injections into the subacromial space will do nothing for pain that is generated in the muscles. 

This may be of use, I'm sure you have come across it but if not, here you go 

http://www.ncbi.nlm.nih.gov/pubmed/21109059

yes Ruth I totally agree with you, as sure you also know that the shoulder pain is often associated with trigger point pain itself , regardless of impingement suffering .

thanks for the appreciation .

a greeting

I don't have any expertise on this area. I would like to comment on Ruth Light, pain is never! generated in the muscles but only in the brain. Things like this is the cause of the idea that damage in the body tissue is 1 on 1 related to the experience of pain.