According to DC/TMD has the same features as local myalgia plus pain spreading. Other form of myofascial pain is myofascial pain with refferal. Pain spreading and pain refferal are thought to result from changes in pain processing caused by nauroplasticity within CNS - central sensitization. 

Hi

You are asking a very relevant question although in my opinion it is not possible to give a good answer.  Both local myalgia and myofascial pain are part of a cluster of terms used to describe unspecific pain conditions that in some way related to muscle tissue.  The common feature of all these terms is that they are based on subjective evaluations of symptoms with no or week connections to an established pathophysiological processes or conditions.  For example, the term myofascial pain syndrome originates from a hypothesis that source of the symptoms is the fascia or connective tissue surrounding the muscle.  What terms are used and what they are considered to represent also varies between countries (or continents), research traditions and disciplines, making it even more difficult to actually understand that kind of patients that are addressed in studies.

In research it is in general good to be as descriptive as possible when presenting the study populations in this area, rather than just presenting a one of these terms. I guess the closes I get to an answer is that rather than focusing on the labels put on the patient, focus on the actual symptoms or clinical indicator you have.

In my opinion, main difference is when there's an active trigger point: if you press the muscle with A-TrP you induce refererd pain to the maxilla and/or mandible. In case of local myalgia/latent trigger point there's just local pain when you press.

Latent TrP may become active.

Treatment: both with physiotherapy, TENS, look for bruxism, hypnosis

Dear Philippe Rault,

Thanks to your very helpful answer