Torsion might be an un-physiological dysfunction

It may seem counterintuitive and somewhat paradoxical, but the sacrum can actually go further into the direction of fixation. However, it cannot move back to physiological neutral or beyond it into the opposite direction without a corrective maneuver. This phenomenon is explained as obeying the Rule of Physiological Motion (dysfunction). The rule defines physiological motions as those motions that are normal based on the design of the structure. For example, the knee primarily flexes and extends and slightly rotates during gait, and these are physiological motions. A lateral blow to the knee induces a valgus movement which is un-physiological.

In spite of the fact that torsions obey this rule, I believe they are not a normative physiological motion, such as part of the gait cycle, per osteopathic theory as described by Dr. Philip E. Greenman,¹² former professor of osteopathic manipulative medicine, as well as physical medicine and rehabilitation, at the Michigan State University College of Osteopathic Medicine, and in most other works on the subject. Rather, it takes a large passive, extrinsic force, in addition to vulnerable positioning, to induce torsional movements and fixations – for example, lifting a heavy object with the spine in full flexion, rotation, and side-bending.

Torsion theory often absent in movement science textbooks

It is noteworthy that the concept of torsion is either trivialized, without justification, or completely omitted in several traditional works and in contemporary works on manual therapy, including physical therapy and sports medicine literature.^13-22 Although torsion may be absent or minimized, these works do address the general concept of SIJD.

A few manual medicine practitioners, such as Dr. John F. Bourdillon ²³ and Dr. Karel Lewit,²⁴ do not endorse a torsion model. Also, a remarkably detailed textbook on joints, Joint Structure & Function: A Comprehensive Analysis, briefly covers the SIJ in less than four pages, but avoids sacral torsions.²⁵ Another thorough textbook, Kinesiology of the Musculoskeletal System: Foundations for Physical Rehabilitation, also limits explanation of sacral motion to nutation and counter nutation.²⁶ The topic of sacral motion is limited to a single page.

Both these textbooks hold a prominent location in my library. If published clinical and basic science studies existed that showed the validity of torsion motion, and utility of treatment for torsion, I believe that these ver thorough texts would then appropriately expand the sections on sacral mechanics. This knowledge gap is a valid clarion call for novel research. Both the above textbooks have an especially strong and relevant explanation of the relationship of the pelvis to the hip and lumbar spine, and the reverse thereof. This description is welcomed by clinicians who perceive pelvic pathomechanics as distinctly different from SIJ movement dysfunction.

Donald A. Neumann, professor of physical therapy at Marquette University, clearly states the problem of the SIJ concept in physical therapy: “Adding to the clinical ambiguity of the sacroiliac is the lack of standard terminology to describe the related anatomy and kinesiology. As a result, the biomechanical and clinical importance of the SIJ is often understated or exaggerated.”²⁷

Torsion theory is evolving

SIJDs can be difficult to diagnose, which can lead to confusion among practitioners. Some who acknowledge SIJD have even begun to doubt the very existence of sacral torsions. Torsions frequently coexist with low back pain, making them difficult to isolate as the underlying issue. Proximal spasm and postural aberration can give the appearance of a primary lumbar or lumbosacral dysfunction, whereas any occulted torsion will be more apparent in a fully flexed posture. On the other hand, many clients are misdiagnosed with SIJD when they are actually experiencing spasms or shortened soft tissues. These tissues can impact the posture and movement of the entire pelvis, hip, and lumbar spine. However, these asymmetries of posture and movement do not necessarily equate to a faulty fixation within the true SIJ.^28,29

Two authors make noteworthy contributions to torsion theory in contrast to most writings, which simply reiterate the traditional theory and treatment without much debate. Osteopathic physician Dr. Myron C. Beal questioned the entire concept of torsions quite some time ago,³⁰, while another osteopathic physician, Dr. Theodore R. Jordan, suggests replacing the joint fixation model with a soft tissue asymmetry model, based on the segmented innervation of the multifidi muscles.³¹

In contrast to Beal and Jordan, I believe that torsion is, in fact, a valid movement dysfunction of the SIJ, and that the lumbosacral facet motion is also altered. I believe this motion is significantly restricted, such that “lumbosacral-sacroiliac joint torsion” might be much more accurate than “sacroiliac torsion.” This complex pattern is worthy of being understood and applied, as opposed to being avoided completely. Unfortunately, as we have seen, SIJD, and especially torsions, tend to be esoteric for the majority. Therefore, more research is required to make SIJD diagnoses more accurate.

In his text Principles of Manual Medicine, Greenman summarized the challenge of the torsion concept with this statement: “Fortunately, biomechanical research into the pelvic girdle is increasing, and as new knowledge is acquired, the theoretical construct provided here may well need modification. Though the exact biomechanics of the torsional movements of the sacrum are unknown, the hypothetical left and right oblique axes are useful for descriptive purposes.”³²

Torsion is difficult to visualize

Several clinicians note that torsions present visual complexity. Physical therapist Allyn L. Woerman³³ asserts, “sacral torsions are perhaps the hardest dysfunction to conceptualize,” which I readily affirm. Sacral torsion is a tri-plane movement dysfunction of the sacrum about an oblique axis. The axes are tri-planar, therefore, the motions about the axes are complex and difficult to visualize. The primary motion is left or right rotation, occurring in the transverse plane. Sagittal plane flexion and extension and frontal plane side-bending are all lesser torsion motions. Flexion/extension and rotation are additive, such that the most obvious asymmetry of the sacrum will be that one sacral quadrant is notably posterior to the other three quadrants. The side-bending component is discernible, although more subtle. In any given anatomical structure, three-dimensional biomechanics are both complex and challenging to visualize. In fact, the majority of clinicians typically evaluate motion one plane at a time. Perhaps a square lettered block, a child’s educational toy that is symmetrical at rest, is somewhat easier to visualize as making a positional change along an oblique axis (Image 2.)