Palpation, is it a skill, an art or an illusion?

This blog is a talk I did recently at a Sports and Exercise Medicine Conference on the role of palpation within our profession, highlighting some of the issues and doubts I have with many of the claims therapists make and beliefs they have with many palpation tests.
However, before I get started, let me make it clear that I am not discussing the THERAPEUTIC effects of palpation or touch, thats another blog completely. Instead I am only discussing palpation in its DIAGNOSTIC and ASSESSMENT capacity and seeing if it stands up to scrutiny to the claims made by many.


Now as a physiotherapist you won’t be surprised to hear me say, I touch people, I prod things, I poke stuff… Maybe you are surprised to hear that, as I know many think I don’t touch my patients at all due to my strong and scathing criticisms I often make about manual therapy.
Well, believe it or not I do touch people. I palpate a wide and diverse variety of people from the old to the young, the fit to the not so fit. I poke them, I prod them, I press them, I pull them in all sorts of ways, in all sorts of positions and in some weird and wonderful places.

Now before this starts to sound like some dodgy confession at a self-help group for ‘Palpators Anonymous’ let me try and explain where I am going with this pre-ramble. What I am trying to get across to you, is that I have palpated a lot of people in my career. In fact, I estimate I’ve prodded about 25,000 people so far, and that’s a conservative estimate.
So I think I can confidently say that I’ve have had plenty of experience in palpation, and can be classed as an expert in palpation.
So as an experienced and expert palpater you would assume that I can reliably feel the difference between a stiff and a loose joint. That I can easily distinguish a tight and tense muscle from soft and relaxed one. That I can readily feel scar tissue, adhesions and ‘muscle knots’ with ease. Finally you would assume that my surface anatomy land marking is second to none and that I can find a structure with ease and tell you if it is in its correct position or not.
Well, To put it simply, I can’t do any of these things, and neither can you, despite what you may think or believe, or even have been told or taught to believe.
It’s a common fallacy and widely held misconception by many in the healthcare profession and the general public that therapists can detect things with their hands and fingers that mere mortals cannot. That they develop some kind of mystical extra sensory perception when it comes to feeling things.
This is bullshit.

Many therapists believe they can develop these powers of palpation through vigorous training, relentless practice and years of experience.This belief delusion starts off very early for most therapists, with tutors filling their heads with nonsense and instructing students to practice the art of palpation in some weird and wonderful ways.
For example, in my first year as a physio student I was told by one of my more eccentric crazy tutors to practice feeling for strands of hair underneath sheets of newspaper! I kid you not, I was told to pull hair out of my head, place them under newspaper and feel for them. This I was lead to believe would improve my sensitivity to touch and improve my skill as a physio. And I have heard similar mind boggling stories, such as feeling for pipes and cables through walls.
This indoctrination and exposure to ridiculous claims of what can be achieved with palpation leaves many therapists believing that they can attain these super human powers of touch, when realistically examined are just beyond the realms of any common sense and rationale thinking, and more importantly beyond any evidence, and it’s a problem that continues to grow and grow within the professions.
For example, I must get at least half a dozen patients each week telling me that they have had another therapist tell them they have felt ‘knots’ in their muscles, or that they have felt excessive tightness or stiffness in some muscle or other tissue, or that they have found a stiff or loose vertebral joint, and the most annoying and misleading explanation I hear patients say is that some, so-called healthcare professional, has told them that something is out-of-place or alignment.
Now you maybe thinking these examples are all true and easily achievable to feel, well I’m afraid to say that these are all classic examples of palpation pareidolia, a term I was first introduced to by Paul Ingram via his excellent blog here http://saveyourself.ca/articles/palpatory-pareidolia.php
Pareidolia for those who are unfamiliar with the word, is defined as a type of illusion or misperception involving a vague or obscure stimulus, which is then perceived as something clear and distinct, it is usually used to describe visual illusions rather than tactile ones…
Such as seeing a face on the surface of Mars which is just a collection of hills and rocks

Or seeing a Disney elephant cartoon character in a cloud shape

Or even a religious icons face burnt into your toast first thing in the morning

Or maybe seeing that religious icon in some more unusual places…

But all joking aside, in musculoskeletal medicine and therapy the phenomenon of palpatory pareidolia can be strong and it can, and does, give a clinician a sense that they can feel something that the literature and evidence tells us we cannot with any degree of reliability or validity. 
Palpation pareidolia results in high levels of misdiagnosis, and direct treatments down wrong and ineffectual pathways, it also adds nothing but confusion and misinformation for our patients, and in worst case scenario’s can extended periods of pain and dysfunction for them, the exact opposite of what we should be trying to achieve.
Now that’s not to say all diagnostic palpation within musculoskeletal medicine is an illusion or unreliable, far from it. There are some good examples of reliable and accurate diagnostic palpation tests.

For example a recent paper by Hutchison 2012 looked at 10 clinical tests used to diagnose Achilles tendinopathy, and they found only direct palpation of the tendon or calcaneus together with the location of pain was reliable and accurate to confirm a diagnosis of tendinopathy

Bachmann in 2004 demonstrated the effectiveness of the Ottawa Ankle Guidelines, that use amongst other criteria palpation testing of the ankle malleoli, the base of the 5^th metatarsal and navicular bones in those who have suffered an ankle trauma. These palpation tests have been found to be highly reliable in ruling in or out suspected fractures, and has helped reduce the number of unnecessary X-rays in A&E departments by up to 40%, great, this is diagnostic palpation working at its absolute best.
And there are a whole host of papers that I could carry on presenting that show diagnostic palpation does have an important, reliable and validated role in musculoskeletal medicine and therapy. For example joint line palpation of the knee to assess for meniscal issues, or palpating the acromioclavicular joint, but, all these palpation tests have one thing in common…

They all use ‘pain’ as a response, either a lack of it or by provoking it.
When it comes to using palpation for other diagnostic purposes such as assessing joint stiffness, or soft tissue tightness without pain to guide us, then this is when the literature does NOT support many of our claims and shows very high levels of variability, and unreliability.

For example, let’s look at one of the most common diagnostic palpation tools used by every therapist I know, spinal segment motion testing. This is when a therapist applies downward PA pressure to a spinal transverse process or facet joint, to feel for stiffness and quality of movement.
Now I’m not going to get into the debate about ‘if’ spinal stiffness produces pain and/or problems, and I’m also not going to dwell on the research that shows our reliability to locate accuratley an individual specific lumbar vertebra is highly questionable, instead I will just look at if the claim thata therapist can tell if a vertebral segment is stiff or not.
Well the major obstacle here is, and always will be, is the high variability in forces applied by therapists when performing these spinal PA tests.

The variability in forces applied during spine mobilisations was first highlighted by Harms and Bader in 1997, (which are two great names for physio researchers by the way) they assessed the forces applied by 30 experienced physios as they performed PA mobilisations to the lumbar spine of one subject on a modified treatment couch with pressure plates. As you can see the difference in forces applied is vast on all grades of mobilisation, but if we just look at when the therapists were asked to press the spinal segment to what they thought was its end of range, we can see some only pressed with about 100N (equivalent to 10kg of load) whilst others pressed up to 3 ½ times harder, over 350N. This clearly means those therapists pressing with higher forces will just not interpret that spine as stiff as those pressing with lower forces.

And there have been many other studies since this looking at the forces applied by therapists during spinal motion palpation tests. These were collated in a literature review by Snodgrass 2006, and although there are differences in study design, methodology, and areas of the spine palpated, making direct comparison difficult, there is clear evidence of the high variability in forces applied by therapists when assessing spinal stiffness.

They concluded that the forces varied so much between therapists that no diagnosis of segmental stiffness could reliably be made in any area of the spine! They attributed this in part due to differences in levels of experience, with physio students and newly qualified therapists pressing with much lower forces and with higher levels of variability, whereas more experienced therapists tended to press harder and slightly more consistently, perhaps showing a learning curve and some skill acquisition in spinal motion palpation. 
However, despite experience there was still wide variation, making any reliability still impossible. They also demonstrated that there is also vast differences in the individual subjects spinal stiffness from person to person, and it is not known what is ‘normal’ spinal stiffness to make any assumptions as to what is too stiff or not, its simply pure guess work.
So if wetake high variability in forces applied by therapists, add the vast differences in individual spinal stiffness, means that any interpretation of spinal stiffness is highly unreliable and based on nothing more than individual interpretation!
Now please understand I’m not to saying we should stop pressing down on spines, and I’m not saying some spinal manipulation in some doesn’t alleviate back pain or improve function, it does, for some, a little bit, for a little while, there are studies that show it does, just about… But we just can NOT press a spine and tell a patient that its too stiff or not.
So please just stop it!

So if we can’t use palpation to tell if the spine is stiff stiffness, how about palpation of soft tissues?
Therapists often palpate soft tissues, feeling for tension, tightness, lumps, bumps or knots, but how reliable are we in finding these things?

Well lets first look at muscle knots or taut bands. These are commonly referred to as ‘Trigger Points’ and there is a huge industry built up around them, with training, education and treatment. Trigger Points where first described by the US physicians Janet Travell and David Simons back in the 1960’s, they described palpable knots and taut bands that can be felt within muscles throughout the body and hypothesised that these are local areas of sustained muscular contraction and hypertoncity that cause pain either locally or referred elsewhere.
These trigger points are thought to be caused by insult to the muscle fibres either directly from trauma, or indirectly from repetitive overload from sustained postures, positions or repetitive activity. This trauma is then thought to releases substances such as histamine, serotonin, kinnins creating a biochemical milieu etc. which stimulates nocioceptors and causes adverse reflex muscle contractions.
To treat trigger points Travell and Simons advocate the use of tissue stretch or direct sustained pressure to them. Many also now use the method of Dry Needling to treat them.
However, to effectively treat a muscle knot or band with these techniques we must first be able to reliably find them, and herein lies a major hurdle and obstacle for the adverse muscle knot theory as a cause of Trigger Points, because when blinded, and pain is not reported, no one, and I mean no one, can find these muscle knots or taut bands with palpation testing alone!

There is a little known study conducted by Fred Wolfe back in 1992 in which he invited the world’s leading experts in trigger points, including David Simons of Travell and Simon, to partake in a blinded randomised comtrolled study, to try and locate trigger points in three groups, those already diagnosed as having them by other experts, a group with soft tissue pain but no muscle knots diagnosed with fibromyalgia, and finally a healthy control group.
So how did these experts do in locating those subjects with muscle knots?
Well unfortunately for the muscle knot believers it was an unmitigated failure, they simply could NOT locate these muscle knots or taut bands when blinded. In fact they found muscle knots twice as often in the healthy pain free control group, and remember these where the best trigger point palpaters in the world!
However much to Wolfe’s dismay and objections the study was almost not published, when it was it was totally fluffed up, a positive spin woven into it, and it was released very quietly and soon forgotten about, it is rarely seen or cited, and the Trigger Point machine happily rolled on and on….

But there is a growing evidence base that supports Wolfe’s first study. A number of systematic reviews such as Hsieh in 2000 who looked at inter examiner reliability for finding Trigger Points in the trunk and lower limb and found none.

Myburgh in 2006 did a systematic review of Trigger Point research and found many, many poor quality studies and that establishing reproducibility of Trigger Points is generally poor.

Lucas in 2009 did another systematic review with similar findings, and concludes that using the current proposed criteria, feeling for knots, taut bands or local twitch or jump responses in trigger point assessment is unreliable.
Now please don’t misunderstand me in saying that I don’t believe in the existence of sore spots found in and around the body, and I don’t won’t get into the debate on WHAT these sore spots are when we press and palpate them, that’s for another day, just to say, that I don’t think they are as described by Travell or Simons, nor do I think we need to treat them as many think they do.
So I hope I have shown that we can NOT palpate spinal stiffness, nor can we feel muscle knots or taut bands.
So how about palpating for things that are in or out of position.

Well palpating for obvious structural deformity after trauma in sports medicine is clearly very useful, if sometimes not really needed as with this poor chap above, but what about the use of palpation to check for more subtle structural positional defects that are commonly thought to cause pain and dysfunction.
The classic area this is routinely done is in the assessment of the pelvis, in particular that of the sacroiliac joint. Now the sacroiliac joint is so full of myths and misconceptions within the manual therapy world it is the grand daddy of palpation pareidolia, and a source of constant annoyance and eye rolling for me.
The sacroiliac joint is thought to be a common source of pain and dysfunction by many if it’s not positioned correctly or if it’s moving too much or too little. Now again I’m not going to get into the debate about IF the sacroiliac joint does or does NOT cause these issues, but rather if we can palpate if its in the right position or if it is moving too much or too little.

To check for a sacroiliac joints position many therapists will commonly palpate for the bony landmarks of the anterior and posterior superior iliac spines (ASIS/PSIS) in a standing position. If the ASIS is too low then the pelvis is thought to be too anteriorly rotated, or if the ASIS is too high then it’s thought to be too posteriorly rotated. These are believed to cause excessive stresses, strains and so pain.
However, if we conveniently ignore the issues around the accuracy and reliability of finding the ASIS or PSIS in some of our more ‘adiposed challenged’ patients, and just look at if the height of these landmarks tell us if the pelvis is in the right position or not. Well the often overlooked issue here is that of normal skeletal varibility.

Preece did a nice little study looking at just this, he dissected 30 pelvic cadavers, and measured the angles between the ASIS and PSIS, and found there was very high variability between the angles of the ASIS and PSIS. With some having these landmarks pefectly level, and others with the ASIS up to 23 degrees lower. This makes any clinical test that uses these landmarks unreliable as how can a therapist tell if these landmarks are higher or lower due to position or skeletal variation? The answer is they cant!

The other common illusion around the palpation of the sacroiliac joint is that many therapists think they can feel it move too much or too little, and decide if it’s too stiff or too loose. However the credibility of palpating a sacroiliac joint move, and I use the word move here very, very loosely, as it’s only a few millimetres at best, under layers of tissue, ligaments and muscles is simply ridiculous, yet this practice is still taught, used and believed widely.

There are many studies that show terrible inter and intra reliability and validity for all these sacroiliac joint movement tests such as Riddle in 2002

And then Robinson in 2006 who found kappa values in the minus figures.

So in summary I hope that I have demonstrated the common issues with diagnostic palpation, and hope I have raised your awareness a little that within the in the world of musculoskeletal therapy a lot of palpation tests have ridiculous, far-fetched and un-evidenced claims.
I hope the next time you hear a therapist explaining to you or a patient that they have felt a stiff spine, or a sacroiliac joint not moving properly, or a knot in a muscle you will remember the role that palpation pareidolia plays.
As always thanks for reading
Adam