The hands figure large in the brain. By comparison to the rest of the body, our brain dedicates gigantic areas of its sensory homunculus (Image 1) to hand sensation. Only the super-sensitive tongue and lips come close to the amount of brain area the hands have. In the case of the mouth, the sensorimotor nuances of speaking and oral expression, as well as biting and masticating our food, are so neurologically demanding that they also require comparatively huge areas of the brain. Like the mouth and face, the hands are also extremely sensitive. This and their similarly intricate motor control require comparatively vast regions of the brain to process, map out, and coordinate. And manual therapists will appreciate that since we have two hands but only one mouth, the total amount of brain dedicated to processing hand signals is, in total, far greater than any other part of the body.

Your hands are truly sense organs. Each hand has about 100,000 nerves, and each of its five fingertips has over 3,000 mechanoreceptive nerve endings, most of which are finely attuned to pressure. Of the 20 different kinds of nerves in the hand, the majority (60 percent) are afferent (sensory nerves, carrying information to the brain), with the remaining 40 percent being efferent (motor nerves, sending movement signals to the muscles of the hand).¹ For hands-on practitioners, these hand facts suggest some interesting thought experiments:

• What would your bodywork be like if, like the nerves of the hands itself, it was 60 percent sensing and only 40 percent “output?” Would that change your pacing, the quality, or the feel of what you do? Practitioners who focus on perception (rather than focusing solely on manipulation) know that client satisfaction is often not related to the amount of practitioner output, but rather on the quality of touch, perception, and interaction.

• Or, what if, in a whole-body session or series, we followed the homunculus’s virtual body proportions when we decide how much time we spend on different parts of the actual body? The back and legs, for instance, would be our focus for only a small fraction of the on-table time, while the hands would take the bulk of the session. This is something like what it would take for the brain to get an evenly distributed whole-body session.

What About Pain?

Though pain involves different nerves than tactile sensation, pain sensitivity is also much higher in the hands (especially the fingertips) than anywhere else on the body. So when the hands hurt, they can “fill” our awareness at the same disproportionate scale they occupy in the brain. But to the extent that pain is a variable response related to protection, rather than a fixed indicator of tissue damage, pain can be modified in many ways. This suggests ways that we, as hands-on therapists, might use the outsized brain representation of the hands to our advantage—filling the brain’s hand regions with benign and even pleasant signals can displace and relieve the experience of pain, not just for local hand pain, but also for pain elsewhere in the body. In practice, starting far away from a painful area is a time-tested strategy for easing pain, with the hands being particularly suited as an entry point for this approach. And parents everywhere know that gently stroking their child’s hands is calming and can lull the most wakeful child into sleep.

Affective Touch

Most any benign hand sensation can probably have a pain-relieving effect. But detailed research into affective touch, that is, “pleasant” touch sensations carried by specialized nerve fibers (C-tactile afferents), has indicted that there are particular body regions (the back side of the arm and hand, for instance); certain pressures (0.3–2.5 millinewtons of pressure—lighter than a postcard); and even particular speeds (3 centimeters per second) that can maximize the involvement of these pleasant-touch nerve fibers.² These slow-conducting fibers project onto the same region in the brain (the anterior insula) as other C fibers, including those that carry temperature, itch, and pain.³

The brushing technique shown in the sidebar (this page) is an example of how we might apply these principles. Though physical therapists sometimes use brushing techniques to facilitate muscle tone and relieve pain (as in the Rood approach), our version is a bit different. Imagine that your gently brushing touch is filling in, revealing or recoloring the brain’s sensate map of the hand, just like a paper rubbing or tracing reveals and recolors a hidden pattern. The therapeutic value of this approach is related to the phenomenon of cortical smudging, where the brain’s body map in people with pain or movement disorders is thought to become blurred (or more accurately, to develop greater overlap between adjacent body regions) like a smudged drawing or out-of-focus picture.⁴ We can use touch, then, to redefine or trace a new, clearer picture onto the brain’s sensory map.

This kind of light-touch approach may also have therapeutic effects on lymph function or on the fluid perfusion within the interstitium (the sponge-like layers of superficial fascia just under the skin), which are intimately involved in inflammation and its resolution (see “Understanding Inflammation and Pain,” Massage & Bodywork, January/February 2019, page 100). Light, brushing touch can have surprising effects on swelling as well as pain.

Key Points:
Brushing Technique

Indications

• Pain in the hand, or elsewhere in the body

• Local inflammation or swelling related to injury, arthritis, etc.

• Stress, anxiousness, or wakefulness

Purpose

• Stimulate C-tactile afferent (pleasant-touch) nerve fibers, and thereby supplant pain experience in the brain

• Refine and recontextualize the sensory representation of the hand in the brain’s somatosensory cortex

• Calm and quiet autonomic nervous system arousal

• Stimulate lymph flow and interstitium perfusion

Instructions

• Use your fingertips or a soft brush to stroke the fingers and hand gently, slowly, and thoroughly (Image 3). Imagine “recoloring” and refining the brain’s hand-representation map.

• Use your client’s feedback to find the optimal pacing, pressure, direction, and duration.

For More Learning

• Webinars: “Myofascial Techniques: Hands-On for the Hands” (New!) and “Working with Inflammation” with Til Luchau in the ABMP Education Center (www.abmp.com/ce)

• Training: “Arm, Wrist and Shoulder” in the Advanced Myofascial Techniques series of workshops, live-online, and recorded video courses (www.a-t.tv)

• Book: Advanced Myofascial Techniques, Vol. 1, Chapters 15 “The Wrist and Carpal Bones” and 16 “The Thenar Eminence” (Handspring Publishing, 2015)

• Podcast: Listen to Til Luchau and Whitney Lowe discuss manual therapy and more on The Thinking Practitioner podcast, sponsored by ABMP, at www.a-t.tv/ttp

Final Thought

Our highly sensitive hands are the means by which we touch, feel, and interact with the world. As hands-on practitioners, we’re accustomed to using our hands to help others. As an experiment, why not use your skilled hands on yourself, with one hand refining, remapping, and recoloring the other hand’s large region in the brain? And when the time is right, you can use this approach with others, to help their brains have different, clearer, and more nuanced experience of the richness of the body.

Notes

1. Elise Hancock, “The Handy Guide to Touch,” Johns Hopkins Magazine (April 1995), https://pages.jh.edu/jhumag/495web/touch.html.

2. Francis McGlone, Johan Wessberg, and Håkan Olausson, “Discriminative and Affective Touch: Sensing and Feeling,” Neuron 82, no. 4 (May 2014): 737–55, https://doi.org/10.1016/j.neuron.2014.05.001; Johan Wessberg et al., “Receptive Field Properties of Unmyelinated Tactile Afferents in the Human Skin,” Journal of Neurophysiology 89, no. 3 (March 1, 2003): 1,567–75, https://doi.org/10.1152/jn.00256.2002.

3. A. D. Craig, How Do You Feel? An Interoceptive Moment with Your Neurobiological Self (Princeton: Princeton University Press, 2020).