The term trigger point or myofascial trigger point was first coined by the America Physician Janet G. Travell.
Travell became the first female personal physician to an American President after helping to alleviate John F. Kennedy's back pain. She wrote many papers and books on the subject of trigger points which are still considered by many to be the most detailed and important writings on the subject to date.
Lots of research has been done on trigger points to figure out exactly what they are and why they appear but there currently aren't any definitive answers. The word myofascial means, muscle (myo) and fascia (fascial) and would suggest that trigger points are located within skeletal muscle although this still hasn't been proven. We often talk about our muscles feeling as if they're all knotted up and this maybe where the idea that trigger points or tender spots are located within the muscle originally sprang from.
What is a trigger point?
Trigger points are tender spots which trigger pain and discomfort. We all experience these pesky little tender or sore spots at sometime or other but for a small number of people they are associated with a huge amount of persistent pain and discomfort. We most commonly feel them in our shoulders and backs but can actually experience trigger points or tender spots anywhere on the body.
Trigger points or tender spots are located within or below the skin and when compressed they will usually become more tender or painful, they're also often associated with areas of pain and discomfort adjacent to or distant from the tender spot. These referred feelings can include a wide range of wonderfully strange sensations from a heavy or dull aching to searing hot pain, pins and needles or numbness to name a few.
The most popular theory on trigger points, and the one put forward by Janet G. Travell and David G. Simons in the book "Myofascial Pain and Dysfunction: The Trigger Point Manual" is that trigger points are located within skeletal muscle.
This theory proposes that there is a motor dysfunction within the muscle that is characterised by a band of increased density called a taut band within the belly of the muscle and a painful spot in the centre of the band.
Several different types of trigger point are described including Active, Latent, Secondary, and Satellite. An active point is one which is currently triggering pain locally and in a referral area, a latent (or dormant) point is only tender or painful when compressed and may or may not also cause discomfort to a referral area. It has been suggested that a trigger point will often cause further trigger points in its referral area and associated muscle groups causing a cascading effect of trigger point creation; these are known as satellite and secondary trigger points.
It is said that trigger points can occur in multiple locations in any muscle, these locations can differ from person to person although rough guides and patterns have been recorded resulting in charts of trigger point locations and associated pain referral areas.
So what causes these trigger points in muscle? It's been put forward that trigger points are created by muscular overload of one sort or another including overexertion, overuse, posture and trauma. Muscular tensions, structural issues, and nutritional deficiencies are said to predispose a muscle to these overloads.
Although the theory that trigger points are located within muscle has been around for over 70 years and is the primary explanation used for them it is not the only theory.
Another theory that seeks to explain the tender spots we refer to as trigger points is based on peripheral nerve pain and were first put forward in a paper by John L. Quintner & Milton L. Cohen titled "Referred Pain of Peripheral Nerve Origin: An Alternative to the 'Myofascial Pain' Construct."
This theory suggests that the functions of a nerve can be dramatically altered with no apparent cause, meaning nerves throughout our body including our skin may become inflamed and irritated without necessarily being compressed or "trapped".
The pain ascribed to trigger points is often similar to that described in cases of peripheral nerve trunk pain, including a deep aching with referred areas of discomfort.
Charts and patterns used to show the locations of trigger points within muscle and pain referral areas often match the sites, and pathways of peripheral nerve trunks and peripheral nerves have been shown to refer sensations to muscles and other soft tissues innervated by that nerve or branch.
I favour the idea that the tender spots or trigger points are irritated peripheral neural tissue instead of overloaded and dis-functional muscle tissue.
Many different methods of treatment have been devised over the years to treat tender spots and trigger points, these including: injecting the tender spot with anything from Botox to saline, a form of acupuncture called dry needling, ischemic pressure that involves pressing the spot very hard for a prolonged period and many other techniques that involve refinements of pressing and stretching in different degrees.
Many of these treatments appear effective some of the time, for some people and are mainly based around the theory that trigger points are located within muscle.
Treatment methods based on the central nervous system and neural tissue are far gentler and less intrusive. When working with the nervous system it is important to provide positive input to the system and this excludes anything painful or uncomfortable which runs the risk of making the CNS feel threatened and produce a guarding and protective response.
A good massage or manual therapist will give you advice on techniques you can do yourself to help ease the tender spots or trigger points, often this will include movement based exercises targeted at the area involved.
Trigger points and tender spots can cause a huge amount of pain and discomfort, often restricting your movement and your ability to do the activities you want to. You don't have to put up with this pain though, with some action on your part you can be pain free!