"The surface area of the skin has an enormous number of sensory receptors receiving stimuli of heat, cold, touch, pressure, and pain. A piece of skin the size of a quarter contains more than 3 million cells, 100 sweat glands, 50 nerve endings and 3 feet of blood vessels. It is estimated that there are some 50 receptors per 100 square millimeters, a total of 640,000 sensory receptors. Tactile points vary from 7 to 135 per square centimeter. The number of sensory fibers from the skin entering the spinal cord by the posterior roots is well over half a million."

- Ashley Montagu⁴

Touch inherently is a two-way sense - we cannot touch without being touched back. We have the sensors to receive far more tactile input from the world than we can consciously process. Thus, habitually, we filter out the vast majority of the sensory input we receive. Without such filtering, we would have a hard time living within our skins, constantly being aware of every contact and friction with clothes and other objects. Yet, in massaging another, we can learn more by training both our conscious awareness and our unconscious filtering processes to better discriminate both client tissue and client responses. Open your sensory filters and explore your awareness of touch. Compare the sensation of touching and holding with slight back and forth movements (sliding touch) or touch with slight vibration. Touch surfaces at different temperatures, with different textures and with different levels of plasticity or give. In touching surfaces with some give, slow down and observe the differences in what you perceive with different pressures of touch. Particularly with touching human skin, muscles and fascia, practice feeling the different layers and the differences in texture, temperature and direction that distinguish them.

One of the classical sensory analogies for deep tissue work is the cornstarch and water solution. In the worlds of children's play and physics, this solution has become known as Oobleck.⁵ Add water to cornstarch in a small bowl until the solution as the consistency of pancake batter when stirred very slowly. If you tap the surface quickly, the surface is hard. Your fingers come away without intermingling with the solution. If your place your fingers on the surface and pause, your fingers sink in. Suddenly the solution is liquid. For deep tissue work, the lesson is one of working slowly and giving the tissue a chance to deform plastically rather than trying to force a rate of movement. In teaching such work, I use the term "glacial creep," literally meaning to apply pressure obliquely to the body's surface and let the stroke move naturally with the plastic movement of the tissue beneath, much as a glacier deforms and moves under the pressure of its own weight. On a sensory level, feel for the give in the tissue and work to enhance that, working the directions of give into the directions of restriction. The sensation is one of eroding the edge of a restriction rather than jumping directly into the middle. Applying pressure and waiting also provides the advantage of making the work easier; you simply relax and lean into the technique, letting your bodyweight do the work while you "hangout" in the tissue waiting for pressure and accommodation to interact.

In looking at good resources on palpation, Philip Greenman gives a thorough overview of palpation skills in his book on manual medicine.³ He divides the process of palpation into reception, transmission and interpretation. Sensation involves the activation of skin sensors by the variations in touch. Transmission is the internal processing of the stimuli. Finally, and likely the most learned and learnable stage, you have to interpret the signal at multiple levels of awareness, your conscious mind analyzing linearly and your unconscious mind matching the signal to previous patterns of experience. Greenman's practice of palpation involves varying the pressure, depth and movement of touch, and noticing differences. How thick, how deep, how warm and how mobile are the tissues?

Leon Chaitow, in Palpation Skills provides an extremely thorough guide to using touch for assessment.¹ He sets five objectives for palpation:

• Detect abnormal tissue texture.
• Evaluate symmetry in the position of structures, both tactically and visually.
• Detect and assess variations in range and quality of movement during the range, as well as the quality of the end of the range of movement.
• Sense the position in space of yourself and the person being palpated.
• Detect and evaluate change in the palpated findings, whether these are improving or worsening as time passes.

Chaitow notes that successful palpation requires trusting the sensory input; paying attention to what is being felt and suspending critical judgment while the process is being carried out. "Critical judgment may be used in interpreting what was felt, but the process of 'feeling' needs to be carried out with that faculty silenced."

Clyde Ford, in Compassionate Touch, describes an exercise in pacing another with touch that provides some additional insights. The exercise itself is simple, having the other person lie supine and actively pacing their breathing with a hand on their chest or abdomen (i.e. the hand is not laying there as dead weight but is actively moved with the breath). Part of the value of the exercise comes in realizing the power of simple attention to another and in attuning your actions to their responses. Another part comes from the opportunity to be still and observe. As you quietly pace their breathing with your touch, you can notice changes in the depth and rate of their breathing, in the tension and overall small movements of their body, in rates of eye blinking, and in coloration of their skin with superficial changes in circulation. Touch and attention are profound and powerful gifts. Value them and use them well and wisely.

References

1. Chaitow, Leon, 1997: Palpation Skills- Assessment and Diagnosis through Touch, Churchill Livingstone, ISBN 0-443-05320-0.
2. Ford, Clyde, 1999: Compassionate Touch-The Role of Human Touch in Healing and Recovery, 2nd ed., Publishers' Group West, ISBN: 1-55643307-7.
3. Greenman, Philip E., 1989, Principles of Manual Medicine, Williams and Wilkins, ISBN 0-683-03556-8.
4. Montagu, Ashley, 1978: Touching-
   The Human Significance of the Skin, 2nd ed., Harper & Row, ISBN 0-060-90630-8.
5. Wikipedia, 2006: Oobleck, http://en.wikipedia.org/wiki/Ooblick.