- Mind Map View
- Introduction to Musculoskeletal Integration Theory
- Chain of Events
- Muscular Adaptations
- The Nutation Lesion
- SIJ Innervation
Since some of the muscles that originate at the innominates insert into the extremities, such as the lattisimus dorsi into the arm, the adductors and abductors into the femur, and the quadriceps, hamstrings, sartorius, TFL and other muscles into the knee, it may be reasonable to look at the sacroiliac joint in evaluating extremity dysfunctions. Once this relationship is understood, the simplicity of the underlying nutation and counternutation patterns makes complex dysfunctional syndromes more tenable. The roles of more muscles, and their effects on structural distortions, can be recognized within this unifying pattern. Thus, the nutation lesion and its ligamento-muscular response present a unifying concept in understanding, preventing, and treating many musculoskeletal injury and pain syndromes.
Due to the stabilizing effect of muscles such as the piriformis and obturator externus on the sacroiliac joint, the femur is rotated externally. With the femur, the foot rotates laterally at such an angle that normal toe-off may no longer be possible. Instead, push-off stresses the first ray and the medial arch of the foot, leading to excessive pronation. On toe-off, the foot may not lock as it should during supination. As a result, the ligaments supporting the medial arch will undergo micro trauma and may eventually weaken, creating instability and chronic hyper-pronation. The ligamento-muscular response is supination, which may or may not develop into hyper-supination, depending on use and chronicity.
As discussed above, the upper leg rotates laterally and the foot may undergo excessive pronation during mid-stance. During pronation, the lower leg rotates medially. The combination of an excessive lateral rotation of the upper leg with a normal or excessive internal rotation of the lower leg stresses the knee, potentially placing significant stress on the medial meniscus. Activities that involve bending, lifting, twisting, while placing weight on the side of lesion, will accentuate the rotational stress on the medial meniscus.
Anterior Cruciate Ligament (ACL) Sprains
The ACL is designed to limit excessive knee extension and internal rotation of the lower leg relative to the upper leg. In addition to sprain occurring in extreme hyperextension, the ACL is frequently torn in severe twisting movements of the knee in which the lower leg excessively rotates internally, relative to the upper leg.
I suggest that repeated micro trauma to the ACL is caused by the same mechanism that leads to excessive pronation and medial meniscus stress. Over time, the ligament weakens and becomes susceptible to rupture. This effect can be magnified by improper coordination between muscle groups that move the joint. As one muscle turns off, the next muscle in sequence should turn on in smooth synchronization. This timing is dependent upon reflexes initiated in the ligaments of the involved joints as they respond to pressure changes during movement. Although the initial thought is to look at the attachments of the hamstrings and quadriceps at the knee, it is suggested that their proximal attachments are just as likely to play a key role in their dysfunction. In the sacroiliac nutation lesion, the hamstrings, more so the medial, are inhibited, while the quadriceps and lateral rotators of the upper leg are contracted. Although these muscles are inhibited or contracted to support the sacroiliac joint, their imbalance may significantly delay load transfer through the knee, contributing to excessive lateral rotation of the upper leg and internal rotation of the lower leg. Over time, microtrauma may weaken the ACL and set up the ligament for a single damaging event.
Contralateral Shoulder Dysfunction
This lesion can be explained as a part of the scoliosis pattern described in Overcompensation Pattern - Structural Adaptations. With a right sacroiliac nutation lesion, the muscles cause the innominates to rotate to the left. To provide balance, the spine rotates to the right and laterally flexes to the right. At this point, the righting reflex causes the shoulders to rotate back to the left and, in order to align the head in an upright posture, the upper spine bends back to the left. As a result, we have different influences affecting the spine. From below, the body will try to protect the sacroiliac joint but, from above, it is trying to balance the body with gravity. This results in a twisting of the spine, which compacts the rib cage on the upper left and lower right. This compaction will alter the position of the upper ribs and may cause some ribs to shift out of place. The scapula will no longer ride smoothly on the rib cage and the mechanics of the entire shoulder girdle will be altered. These mechanics are induced by a combination of muscular actions that influence both shoulders in different manners.
Try this simple self-demonstration, starting from the erect neutral position. 1. Keep your feet in place and turn your pelvis to the left to the end of range of motion. 2. Keep your pelvis to the left and turn your lower trunk to the right so that your left shoulder moves towards your right hip. 3. Straighten your trunk and twist your shoulders and upper back to the left. 4. Straighten your right knee and make sure that your weight is evenly distributed on both feet. You should feel tightening in the upper left and lower right rib cage. In that position, flexing the thoracic spine at different levels will change the stress points in the rib cage and spine.
Please see Overcompensation Pattern - Structural Adaptations for associations between the Nutation Lesion and:
- Facet Syndrome
- Lateral Canal Stenosis with Nerve Root Impingement (e.g. Sciatica)
- Lumbar Disc Herniation
- Lumbosacral Hypomobility
- Anterior Thoracic Vertebrae
- Pelvic Torsion: AS/PI
In the future, I will describe associations between the Nutation Lesion and the following:
- Hip Degeneration
- Patellar Tracking Dysfunction
- Piriformis Syndrome
- Pudendal Nerve Entrapment
- Thoracic Outlet Syndrome
- Spinal Subluxations
- And more
More research is needed.
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3. Panjabi, M.M., A hypothesis of chronic back pain: ligament subfailure injuries lead to muscle control dysfunction. European Spine Journal, 2006. 15(5): p. 668-76.
4. Lovett, R., The Mechanism of the Normal Spine and its Relation to Scoliosis. Boston Medical and Surgical Journal, 1905. CLIII(13): p. 349-358.