There two fundamental pelvic patterns. The first fundamental pelvic pattern is the anterior pelvic tilt.
This pattern entails the anterior pelvic tilt with an ischial widening, which then has a follow-on effect.
“The ilia draw together in the front and anteriorly rotate in the sagittal plane. The superior pelvic bowl narrows. The sacrum nutates and the coccyx moves away from the symphysis pubis …The dimensions of the inferior pelvic bowl and the pelvic floor enlarge….The lumbar lordosis increases as the spine moves into extension. The hips move into relative flexion. This pattern is fundamental to any movement which requires flexing or bending at the hips e.g. sitting or bending forward in standing.” (Key, 2010)
The second fundamental pelvic pattern is the posterior pelvic tilt.
This pattern involves a posterior pelvic tilt with ischial narrowing. The follow-on effect of this scenario is:
“The ilia not only spread apart but they also posteriorly rotate. The superior pelvic bowl ‘opens’ more. The sacrum counter-nutates and the coccyx moves closer to the symphysis pubis. The tail bone is ‘tucked under’. The dimensions of the inferior bowl and pelvic floor or pelvic diaphragm become smaller – the lower pelvic bowl ‘closes’. The lumbar spine moves into relative flexion. The hips move into relative extension. This pattern is fundamental to any movement requiring opening and extending at the hips e.g. sitting to stand; backward bending in standing.” (Key, 2010)
Both fundamental patterns occur naturally and are part of normal life. However, these patterns become problematic if people use them habitually a rest position. The consequences of adopting these positions habitually can include back pain, but also – sometimes painful – changes in the lower limbs and feet.
Implications for the pelvic floor
The first fundamental pelvic pattern (anterior pelvic tilt) leads to an opening and widening of the pelvic floor, while the second fundamental pattern (posterior pelvic tilt) leads to a narrowing of the pelvic floor. Again, the problem does not arise from occasionally being in those patterns, but from habitually using these patterns. Muscles (most of them) like to contract and relax often to be healthy and functional. They should not stay in one position. The pelvic floor muscles are no exception. If the pelvis is in a neutral position when we have to stand or sit for long periods of time (we shouldn’t, but we do) the muscles can be in their optimal position and don’t get used to dysfunctional patterns.
The ‘anterior tilt people’ tend to develop a weakening of the pelvic floor which can lead to stress incontinence. ‘Posterior tilt people’ tend to develop a tightening of the pelvic floor which can lead to sexual dysfunction or difficulties with urination. This second pattern gets aggravated if people also clench their butts.
Key, J. (2010). Back Pain – A Movement Problem. Edinburgh: Churchill Livingstone Elesevier.