Assessment of Tonal Asymmetry – A useful guide to the effectiveness of treatment

This article assumes the reader has previously read and understood the article entitled “Textbook Theory”, which may be viewed on line at

Anyone who has read the book or taken the class will find they already have a solid understanding of this information.  I have posted this article for readers who do not have access to either the book or the class.


In practice, Mr Bowen would most certainly have conducted a tactile assessment of every patient in order to identify abnormal tissue tone and he would have interpreted such tension as an indication of nervous system dysfunction. Indeed, when patients questioned Mr Bowen, seeking an explanation of their problem, he frequently replied, “You have a pinched nerve”.

The following questions were put to Mr Bowen during the parliamentary committee interview in 1973 (Bowen’s responses are shown in italics). His responses indicate the importance he placed on palpating muscles (and nerves) for abnormal tone and tension.

What is your method of treatment? –– Through my fingers and nerve pressure

How do you know you are on the nerves? –– I get the vibration from the nerve

You pick that up through your fingers? –– Yes

You say you have this feeling in your fingers, does that mean you mainly treat muscles?          –– Muscles and nerves

There must be very few nerves that are big enough?    ––You receive the contraction from the muscles


The following information is a guide to recognizing tonal asymmetry.

dural drag 014

Figure 1 : Tonal Asymmetry


Finding the functional short leg…

The Textbook approach begins with an examination of the central axis of the body in order to determine which side of the body is the tighter side and therefore the side with the functional short leg.  The patient should be positioned lying face down (prone) and comfortable.  Pillows and blankets may be placed strategically to ensure that the patient feels as comfortable as possible.

While there are many ways to assess functional asymmetry, the main method that we will describe here involves assessment of the tightness in the lower back or legs.

There are three simple ways for the Bowen therapist to assess for tightness in the lower back or legs:

  1. Perform Lumbar moves 1 & 2
  2. Assess the tension of the Achilles tendon
  3. Observation of a visual short leg.


  1. Perform lumbar moves 1 & 2 to identify the functional short leg

The majority of, if not all, Bowen therapy starts with two medial moves over the lumbar paraspinal muscles at the level of L4.  These moves allow you to assess and compare the relative tightness of the left and right side.   Indeed, Bowen is often quoted as having certain “rules” for the technique.  One such rule is, “Always do Lumbar moves 1 & 2 at the start of any treatment”.

The obvious reason for this being the starting point of any treatment is that the correct tactile assessment of these paraspinal muscles will reveal any asymmetric tension or drag. By commencing treatment here, the experienced practitioner can immediately identify the functionally short leg.  Perhaps a better way of articulating this “rule” for the Bowen therapist would be to “always commence a treatment by assessing tightness in the lumbar paraspinal area with Lower Back moves 1 & 2”.


Lumbar 1 & 2

Figure 2:  Lumbar moves 1 & 2


Note:  In my practice, I routinely follow these moves by moving laterally over the belly of biceps femoris just below the gluteal fold.  The purpose of these moves is the same as Lumbar moves 1 & 2 – to assess symmetry in tissues on either side of the spine.

There will be other notable asymmetry when the short leg is identified and the following procedures will help confirm your findings.


  1. Assess the tension of the Achilles tendon to identify the functional short leg

Assessment of tension in each Achilles tendon will reveal a relative tightness in one. The tighter tendon is associated with the side of the short leg.

The optimum procedure for assessment of Achilles tendon tension is set out below:

a).  The patient must be lying prone with the ankles protruding past the end of the treatment table. The patient’s body should be ‘straight’ (Visualizing three parallel lines can be helpful to ensure the patient is lying straight on the table (see Figure 3)).  The subject’s head should be straight (not turned to one side).   The therapist should flex the patient’s knees to ninety degrees, three times.  This preparation ensures that the patient is relaxed and is neither trying to help nor hinder the assessment process and it also helps to clear any compensation pattern from the patient’s system.

Figure 3:  Visualizing three parallel lines

Figure 3:  Visualizing three parallel lines to ensure the patient is lying straight

b).  The therapist stands at the base of the table with eyes directly above the soles of the patient’s feet.

c).  The therapist places the pad of his thumbs onto the soles of the patient’s feet, over the distal end of the fifth metatarsals, and gently presses the feet into dorsiflexion. The feet should be moved in this manner until the soles are perpendicular to the table surface.

While applying gentle pressure in this manner, the therapist is “observing” the base of the heels and noting any leg length difference as well as “feeling” the tension in each Achilles tendon.  In the uncomplicated patient, the shorter leg is on the side of the tighter Achilles tendon.

Achilles test

Figure 4: Assessment of tension in the Achilles tendons



  1. Observation of a visual short leg

Visually examine the leg lengths using the method described above.  It is important that the feet are in a position of dorsiflexion when making a visual comparison.

The therapist should always remain mindful that artifacts can create the visual appearance of a long leg on the tight side.  In more than ninety-five per cent of cases, there will be no artifact present and the therapist will observe that the tight side is also the side which appears visually shorter.  In the rare event that the tight side appears to be longer, the therapist should enquire as to possible artifacts and the findings should be recorded for future reference.

short left leg

Figure 5: Observation of a short left leg


Performed at the beginning of a treatment, the three procedures described above will allow the therapist to determine which side is the tightest – and therefore identify the side of the functional short leg.

Having identified the side of the short leg, our main concern would then be to locate the tissue tensions that are sustaining it.  The short leg serves as a reference point that will resolve when function is restored to the nervous system.  It serves as a useful pre-test indicator of dysfunction that the therapist can use as a reference point both during a treatment session, and also from one treatment session to another.



Example:  The following example is an attempt to illustrate the points just made.  For simplification, this example assumes there is only one layer of dysfunction affecting the patient.

A patient presents to the clinic with a description of their symptomatology.  On performing moves 1 & 2 of the Lower Back Procedure, the left paraspinal tension is found to be elevated compared to the right.  Assessment demonstrates increased dural tension in the left Achilles tendon.  On visual comparison, the left leg appears shorter.

In this example, the functional short leg is the left leg.  Symptoms commonly experienced by the patient in such a situation may be many and varied – for example,  right-sided hip pain, or left-sided posterior sciatic pain, or right-sided lateral sciatic pain, or dysmenorrhoea, or idiopathic inflammation of the knee (left or right), and/or headache etc..  Indeed, the list of symptoms that could accompany this presentation is probably endless.

When the therapist locates and releases the particular tensions that are sustaining the short leg, it will resolve, indicating a return to function for the nervous system and associated structures.  The associated symptomatology is then expected to resolve.