In order to maintain the center of gravity over the feet or one foot while the other is off the ground chest is moved to different positions. Even the position of the arms and head will require small adjustments. With decades of experience it has become apparent that this is accomplished best by what is considered an insignificant muscle pair called psoas minor. This muscle originates on the front of the spine overlapping the last thoracic and first thoracic vertebra. It inserts into the front of the pelvis just in front of the hip socket. When functional as intended it maintains tension so that the top of the lumbar is centered over the pelvis lengthening on one side and shortening on the other to move the center over the hip socket.
Core of the core Many instructionals refer to the core muscles between the thoracic and pelvic regions as sential for stability and function. Many focus on the surface muscles but that is not the core of the body just as the skin of an apple whether smooth and symmetrical or lumpy and scared does not accurately reflect what the core of the apple around the seeds is like. I have frequently bit into a large perfectly appearing apple to discover a large empty cavity in the center where the seeds should be. That is the apple core. It should have at its center filaments from the blossom end to the stem that support and feed the seeds. Without that the apple may be good for food but not its core purpose to reproduce the apple kind. Psoas Minor As described above the psoas minor serves this core of the core function in producing motion or maintaining a working position. It is often not considered and when it complains the pain is easily attributed to surrounding tissues. Palpation of the belly of the psoas minor do to its size and location between the underlying psoas and abdominal contents are hard to distinguish. Therefore palpation should be indirect by its action on the origin and insertion. This requires the practitioner to develop the skill of motion palpation. That is being still and having the client make an appropriate movement. Asymmetrical or inappropriate timing of movement is the indicator of the problem. Motion palpation at T12/L1 Dr. Robert W. Lovett in his study of motion of the spine and scoliosis during the early decades of the 1900’s established the Law of Reciprocal Rotation of the spine. I have his book Lateral Curvature of the Spine and Rounded Shoulders 4th edition 1922 page 51. “Although scoliosis is generally studied and classified as a deformity of the spine, the laws of equilibrium of the body are such that any deviation of the vertebral column must disturb the whole balance of the body, and scoliosis is , therefore , accompanied by compensating lateral displacement of the pelvis and legs. In this wider sense scoliosis is to be regarded as a deformity of the whole body, especially manifest in the spine.” My finding over the last 25 years is that posture distortions that stress the sequencing of the psoas minor will manifest by an asymmetrical motion at T12/L1. You may find that the motion dominant to one side or you may find that the action is dominant on L1 on one side and T12 on the other causing a rotational subluxation at T12/L1. Rotational paraspinals may chronically tighten on one side and be inhibited on the other. Motion palpation at groin insertion Chronic facilitation of one psoas minor and inhibition of the other can be a causative or result of pelvic distortion. Presentation may be a complaint of pain in the groin or only difference of sensitivity during active change in position. Palpation can and should be done standing, seated and supine following the standing, seated and prone palpation of the motion at T12/L1. Because of the sensitivity of location I first show the client an illustration of the psoas minor and explain what we are looking for. The insertion is on the posterior side of the ramus of the pubic bonein line with the hip socket, therefore accessed by sinking into the abdoman. Then I have the client place a finger beside myne to feel the difference themselves. This is important for their future self care to relieve the imbalance in their posture. There may be tenderness from chronic compensations on either side by adductors under the pubic bone or the abdominals above the pubic bone and possible irritation of the passage of the iliopsoas complex through the groin. Effective self care for the psoas minor Tool, a large ball, The largest Play Ball commonly sold at cain stores is often sufficient but some with longer legs find a larger exercise ball better. Lay on back with legs over the ball, Push with one elbow to cause the latissimus dorsi to turn the spine to that side allowing the pelvis and legs to rotate the ball to the opposite side. Stop with any discomfort or if the other arm is triggered to push back to stop the twist which is a good sign. Reverse with the other side Perhaps palpating for differences in the groin and spine found earlier. The client can self palpate the spine by placing the back of the hand against the thoracic lumbar junction. Progressive steps are: place the heels on the ball and roll the ball in a circular motion then in the opposite direction then with advancement in a figure 8. Advanced is to maneuver the ball with the soles of the feet to develop sequencing movement of the bones in the feet, ankles and knees with the pelvis and spine. That will be the subject of another article.