The English word sacrum is a shortening of the Latin os sacrum or “sacred bone.” Prior to the mid-1700s, this bone was called holy bone in both English and German (heiliges Bein), where it is now referred to as the Kreuzbein (or “cross” bone).1
The “sacred” or “holy” connotations of this bone’s name are mysterious; theories include the cross-shaped appearance of this bone in some animals; its supposed role in animal sacrificial rites, due to its proximity to reproductive organs; and its being the last bone to survive cremation in a sacrificial pyre.2 Since the original Greek root can be translated as either “sacred” or “strong,” others conjecture that the Latin “sacred bone” was simply a mistranslation of “strongest bone”; interesting to us, since the sacrum, as the largest vertebral structure, bears the weight of the entire spine.3
Word origins aside, the sacrum (Image 1) has a unique significance in many manual therapies as well. Osteopathic manipulation places special importance on sacral dynamics, and, of course, it figures prominently in the craniosacral approach that traces its roots to osteopathy.4 Structural bodywork emphasizes the sacrum’s role in weight transfer from the upper body to the supporting lower limbs and its function in mediating the movements between the left and right ilia and legs.
Autonomically, the sacral region is significant for its high concentration of parasympathetic nerve ganglia involved in visceral function (the “old vagal” branch), responsible for both deep relaxation and for primitive biological responses to trauma.5 It is also the site of the ganglion impar, the single unpaired ganglion at the convergence of the left and right sympathetic trunks just anterior to the sacrum’s juncture with the coccyx (Image 2). In yogic philosophy, the coccyx is the site of muladhara chakra, where the ida and the pingala (the two energetic flows of the body) meet and are united.6

The Pelvic Lift
Ida Rolf, PhD, the originator of Rolfing structural integration, finished most of her sessions with a pelvic lift maneuver, most likely inspired by her study with osteopath Amy Cochrane in the 1940s.7 More recently, author and structural integration teacher Thomas Myers (“The Pelvic Lift,” Massage & Bodywork, January/February 2013, page 96) described Ida Rolf’s technique this way:
“In the pelvic lift, the client, supine with her knees up, rolls her pelvis up from the tailbone until the lumbars are off the table. The therapist slides a hand, palm up, under the lumbars, stretching and easing tissue along the posterior of the lumbars and sacrum as the client brings the pelvis slowly, segment by segment, back down to rest on the practitioner’s hand …
Hook your fingertips (by flexing your fingers) into the tissue on either side of the spine and draw downward toward the tailbone … be sure that your pull is straight toward the client’s heels, not in a curve.”
What was the purpose of Rolf’s pelvic lift? There were many. Myers quotes an archival list of 18 “Possible Pelvic-Lift Objectives” that includes “disengage sacrum from L5” (#1), “lengthen the thoracolumbar fascia” (#8), and “ground client—stimulate parasympathetic autonomic tone” (#16).8

Floating Sacrum Technique
As an alternative to the direct-traction technique described above, we often close our Advanced Myofascial Technique sequences with a less directive, listening-based version of this sacral technique. A lighter, more receptive approach at the end of a session helps end things on a quiet note, since subtle types of work can be deeply calming. And rather than add more input, more information, or more manipulation from the outside in, the receptive approach of this technique also gives the client’s somatic awareness time to register her own internal bodily perceptions from the inside out.
Begin by making sure your client understands why you propose working in this potentially personal area. Once you have clear agreement, ask your client to lift the hips just high enough so you can place your hand squarely and comfortably under the client’s sacrum (Image 3), as described for the pelvic lift on page 108. Your other hand can rest on the client’s knees, abdomen, or elsewhere (Image 4). Rather than immediately hooking in or applying traction to the sacrum, simply allow the sacrum to rest on your hand. Let the sacrum come to you, like a boat settling into the water. Be sure you are comfortable and easy in your own body; this will ensure your touch is as receptive as possible.
Rather than move the sacrum, feel for whatever movements it is already making. In most cases, the breath motion will be clearly palpable here; by waiting, quieting, and listening even more, you’ll become aware of other small, slow motions of this bone. It’s not uncommon to feel the slow, longitudinal rocking of the sacrum within the pelvis (the craniosacral pulse), which is said to have both longer and shorter cycles. You may also feel other motions: slow drifting, dropping, swiveling, or side-to-side motions. Don’t let your ideas of conventional physics or joint biomechanics limit what you feel. Likewise, resist the urge to exaggerate, resist, correct, or manipulate these sacral motions for now; simply follow whatever motions you feel, or think you feel. Supporting the sacrum in this way can be profoundly relaxing for your client and will often produce a much deeper experience than more pushing, pulling, massaging, or manipulating.
You’ll know enough time has passed when you notice one or more of these things:
• A shift in your client’s movement rhythms (typically a slowing down or a moment of stillness).
• A sign of autonomic change (such as a twitch, deep breath, eye flicker, etc.).
• Your own sense of finality (though it’s usually best not to use your own restlessness as the only guide to timing your techniques).
Remove your hand, either by having your client reverse the process of lifting the hips off the table or by using the traction described above to end with a sense of length in the lumbar spine, and be sure to allow your client time to savor and soak in the restful quiet this gentle technique can engender.   

Notes
1. C. H. Th. Schreger, Synonymia anatomica. Synonymik der anatomischen Nomenclatur. Fürth: im Bureau für Literatur (1805); J. Grimm and W. Grimm, Deutsches Wörterbuch, University of Trier, accessed October 2015, www.woerterbuchnetz.de/DWB/?sigle=DWB&mode=Vernetzung&lemid=GK13393.
2. Frank P. Foster and William C. Ayres, An Illustrated Encyclopædic Medical Dictionary (New York: D. Appleton and Company, 1891–1893).
3. Online Etymology Dictionary, accessed October 2015, www.etymonline.com/index.php?term=sacrum.
4. Foundations of Osteopathic Medicine, ed. Anthony Chila (Lippincott Williams & Wilkins, 2010): 575.
5. Stephen W. Porges, The Polyvagal Theory: Neurophysiological Foundations of Emotions, Attachment, Communication, and Self-regulation (New York: WW Norton, 2011).
6. R. Upadhyaya and G. Sharma, Awake Kundalini (Lotus Press, 2006): 99.
7. Mary Bond, “The Pelvic Lift: Theme and Variations,” accessed October 2015, www.healyourposture.com/wp-content/uploads/2012/02/pelvic-lift.pdf.
8. Thomas Myers, “The Pelvic Lift: A Rolf-Approved Session Finisher,” Massage & Bodywork, January/February 2013.

Authors note: an expanded version of this column will appear in my upcoming book, Advanced Myofascial Techniques Vol. 2, to be published early 2016 and available at Advanced-Trainings.com.

Til Luchau is a member of the Advanced-Trainings.com faculty, which offers distance learning and in-person seminars throughout North America and abroad. He is a Certified Advanced Rolfer and originator of the Advanced Myofascial Techniques approach. Contact him via info@advanced-trainings.com and Advanced-Trainings.com’s Facebook page.