In this blog post, I am going to continue the discussion of how the body works as a unit and specifically how the hip, pelvis, and spine influence each other. You will be able to understand and feel this relationship with 3 simple experiments...
- Hip joint: flexion, extension, internal rotation, external rotation, abduction, adduction
- Sacroiliac joint (SI joint): very limited rotation and translation
- Pubic symphysis: very limited rotation and translation or shift
- Joints of the vertebral column: flexion, extension, rotation, lateral flexion
Experiment 1: the femur and pelvis relationship
When you turn your feet out you should notice your pelvis tilt backwards or posteriorly slightly and when you turn your feet in you should notice your pelvis tilt forward or anteriorly slightly. This is normal function of the hip joint. If you did not feel that happen or felt tightness, pain, or could not rotate your legs into these positions, this means you have dysfunction in your hips.
The opposite experiment you can do is tilt your pelvis and notice how that changes your femur position (rotation). When you tilt your pelvis anteriorly your femurs should rotate internally and when you tilt your pelvis posteriorly your femurs should rotate externally. (Again if that doesn't happen for you, it is a sign that you have hip dysfunction).
Someone with excessively tight external femur rotators or pelvic flexors can have externally rotated femurs but a posteriorly tilted pelvis. The opposite can also be true where someone has excessively tight internal femur rotators or pelvic extensors can have internally rotated femurs but an anteriorly tilted pelvis. These posture imbalances create massive amounts of stress and friction in the hip joint which can lead to many hip problems including osteoarthritis over time.
Experiment 2: the pelvis and spine relationship
When you rolled your pelvis forward (anterior tilt) you should have noticed your lumbar spine arching (extending). When you rolled your pelvis backwards (posterior pelvic tilt) you should have noticed your lumbar spine flattening or rounding (flexing). This is the normal relationship between the pelvis and spine via the SI joints and joints of the vertebral column.
But just like what we talked about earlier that can happen at the hip joint, muscle imbalances can override normal joint function. When this happens at the SI joints, the increased stress and torque at the SI joints often creates excessive movement at the SI joint(s) that can lead SI joint dysfunction, SI joint arthritis, ankylosing spondylitis, and other problems. When the pelvis and intervertebral joints normal function is overridden by muscle imbalance and dysfunction, the results can be herniated discs, spondylosis, spondylolithesis, degenerative disc disease, scoliosis, and many other problems.
Experiment 3: unilateral imbalances relationship
When your feet were pointed straight ahead your pelvis and spine should have been square and even. When you turned your right foot out you should have noticed the right side of your pelvis rotated backwards and tilted posteriorly slightly and your spine rotated slightly to the right. When your turned your right foot in you should have noticed the right side of your pelvis rotated forwards and tilted anteriorly slightly and your spine rotated slightly to the left. This is what happens with left to right imbalances and is what can contribute to scoliosis.