For our purposes here, consider pelvic “tilt” and “rotation” synonymous unless otherwise indicated.
Some anterior pelvic tilt is normal in both males and females. The current “norms” are between approximately 4 and 7 degrees of anterior rotation in males; 7 and 10 degrees in females. However, these ranges differ somewhat among sources. We assume “neutral” range as within the current approximate norms for each gender in the discussion below. Therefore, “anterior tilt” means rotation forward in excess of norm; “posterior tilt” means rotation back in excess of norm.
The human pelvis is made up of three separate bones — left innominate (ilium), right innominate (ilium), and sacrum/coccyx. The upper leg bones connect to the pelvis at the hip sockets (acetabula). The bottom of the lumbar spine connects at the top of the sacrum.
Pelvic tilt is the amount of change in orientation between the pelvic bowl and the upper leg bones, as well as its orientation in space. Pelvic rotations we discuss here occur in two directions about a side-to-side axis through the hip sockets:
- Anterior pelvic tilt – Where the top edge of the pelvis (iliac crest) is rotated forward and bottom edge (pubic bone) is rotated backward.
- Posterior pelvic tilt – Where the top edge is rotated backward and bottom edge is rotated forward.
- Hemi-pelvic tilt – Where one innominate appears rotated anteriorly or posteriorly in relation to the other. The other may either be rotated in an opposite direction or remain in neutral.
- Lordosis – The natural concave “C” curve in the lumbar and cervical spine.
- Hyperlordosis – Excessive “C” curve in the lumbar and cervical spine.
- Kyphosis – The natural convex or rounded curve in the uppermost thoracic spine.
- Hyperkyphosis – Excessive convex or rounded curve in the uppermost thoracic spine.
Pelvic Tilt Described
Pelvic tilt occurs in people of any age or sex. Functionally, the pelvis should live in a neutral state (as described in Terms above) and balance properly with the legs (femurs) below and spine above. The three bones of the pelvis can move in relation to one another a very small amount. While pregnant and during childbirth, women’s pelvic bones can (and must!) shift dramatically, temporarily. They can also shift in both sexes about several different axes of movement as a unit as required. Dysfunctionally, the pelvic unit shifts out of a neutral alignment in relation to the sacrum and lumbars and upper femurs to an exaggerated angle. This throws off alignment for the rest of the body.
Since the pelvis is in the approximate vertical center of the body, its relationship with the spine and legs is very important for posture and symptoms and compensation patterns resulting from dysfunctional posture. In lower crossed syndrome, for instance, the pelvic bowl as a unit becomes anteriorly rotated excessively. Problems can also occur in the central and peripheral nervous systems because of misaligned vertebral bones, and can affect abdominal organs. Needless to say, it is advantageous to maintain a healthy, neutral position of the pelvis.
As previously mentioned, pelvic tilt approximately occurs about an axis of a line drawn from one hip socket to the other. An anterior pelvic tilt is the next commonly found orientation of the pelvis after neutral in both genders, but more prominently in females. Different theories exist as to the cause. What is important to understand, however, are the biomechanical and neuro-musculo-fascial changes and compensations which occur when the pelvis is tilted and to have some idea of why tilt takes place.
(Please note the consideration of “neutral” in the second paragraph in Terms above.) When in neutral, the various connections with the upper and lower skeleton are aligned in such a way as to distribute the weight of the entire body naturally and with the least amount of stress on joints, soft tissue, and bone. The sacrum serves as a base for the upper torso, head, neck, and arms when level. Wear and tear on the lumbosacral junction (L5/sacrum) is minimized. Our hip sockets, known as acetabula, are properly oriented to fit the heads of the upper leg bones (femurs) as the true ball and socket joints they are intended to be. Stress at these joints are as balanced and minimized as possible. When the body is seated in correct posture, weight is distributed on the “sits bones” (ischial tuberosities).
Anterior Pelvic Tilt
The sacral base becomes unlevel when the pelvis tilts forward excessively. Gravity acts upon the joints nearest to the L5/S1 vertebrae in the spine and at the sacroiliac joints on either side of the sacrum. Complicating things further, the two bottom-most spinal segments (L4 and L5) ordinarily rotate in opposition to each other when walking and running. If the sacral base is unlevel, the L5 vertebrae becomes improperly and poorly supported. The angle between it and its neighbors increases. Abnormal stress and resulting wear and tear then occur to the disc material between the vertebrae. This may cause localized pain or may contribute to sciatic pain travelling down the backs of the legs.
Seen more often than unleveling of the sacral base are the complicated structural concerns that arise. The sacrum itself may nutate, counternutate, or become stuck against an articulating ridge of the ilium, creating a painful jamming at the sacroiliac joint.
More Anterior Tilt Complications
The hip sockets into which the femoral heads reside orient differently with excessive anterior tilt. This causes the head and neck of the femur to swing horizontally forward, causing an internal (medial) rotation of the leg. Rotation then continues down to the foot where it gives the appearance of the person walking “pigeon-toed”. The foot also pronates, meaning that it rolls toward the big toe, drops the arch, and flattens the bottom of the foot.
Anterior tilt is readily seen in the low back by an exaggerated low back curve. When functionally caused, low back muscles and hip flexors become chronically tight and may be sore. Abdominal, gluteal, and hamstring muscles become chronically weak and neurally inhibited. These muscle imbalances result in the appearance of a bulging belly, an often forward-leaning upper body. With a forward center of gravity, body weight is felt more beneath the toes and balls of the feet than under the heel.
Posterior Pelvic Tilt
While posterior rotation is not uncommon in healthy individuals, it is found far less frequently than standard pelvic angle. A posteriorly-rotated pelvis affects alignment of the skeleton as well. The pelvis is turned under, flattening the low back and reducing or eliminating the low back curve. Without the lumbar curve, shearing forces transmit downward through the lumbar spine, resulting in a pinching feeling at the top and bottom of the lumbar spinal section.
The hip sockets reorient the femoral heads, too. This causes the head and neck of the femurs to swing horizontally backward, resulting in an external (lateral) rotation of the leg. Where an anterior tilt causes legs to rotate inward, a posterior tilt rotates legs outward, and is evident in the feet appearing to splay outward.
Causes of Pelvic Tilt
Pelvic tilt occurs for many reasons and causes can be quite complicated. The pelvis suffers from both cause and effect, meaning that pelvic dysfunction may cause other problems elsewhere and problems elsewhere can cause problems at the pelvis. Worse still, problems at the pelvis caused elsewhere can result in further complicating the original problem — a continuous cycle of dysfunction causing pain, that pain increasing dysfunction and causing more pain.
Let’s start at the feet and work up in looking at the various causes and effects.
- One or both pronated or supinated feet can cause rotation of the legs, which causes discomfort or pain at the hip. To compensate, the pelvis tilts to lessen the strain at the hip joint. That tilt eventually hurts the low back and destabilizes the body’s core. Curves in the spine compensate, throw the head and neck forward.
- Leg length discrepancies, which to some degree occur in a majority of the population, throw off the leveling at the hip. Pelvis compensates by tilting the short leg side of the pelvis posteriorly. A sideways strain occurs at the low back and a scoliotic “C” or “S” curve develops in the spine to keep the eyes level.
- The knees. All kinds of knee problems, habits, surgeries, muscular or nerve dysfunction, predisposition (disease, genes, structural deformity), etc., can all result in action taking place at the knee. Most can result in a bowing in or out of the knees in relation to the proper angle between upper and lower leg bones. If the legs bow in (valgus knee), the pelvis will rotate forward to compensate. Bowing out (varus knee) results in a backward rotation of the pelvis.
- Muscle laxity in the legs, hips, or abdomen leaves the body without proper core stabilization, so the joints compensate for the instability. A series of dysfunction takes place and crossed syndrome tilts the pelvis, freezes the hip joint, separates the pelvic bones from each other or jams them together, etc.
- Carrying a baby prenatally. The extra weight pulls the belly forward, the pelvis rotates anteriorly, etc.
- Poor sitting or standing posture. This can go both ways, too — poor posture causes pelvis to tilt and tilted pelvis causes poor posture. Slouching tends to posteriorly tilt the pelvis; sitting bolt upright tends to rotate the pelvis forward.
- Rounded shoulders and forward head posture rounds the low back, posteriorly rotates the pelvis, naturally. Rounding the shoulders with a forward neck posture, but holding the low back from rounding, causes a person to anteriorly rotate their pelvis in order to compensate.
- Any number of genetic predispositions and deteriorating diseases can cause excessive pelvic tilt.
Is Pelvic Tilt Correctable?
Correcting functionally caused pelvic tilt with manual therapy will avoid permanent damage to musculoskeletal structures. Permanent damage from pelvic tilt can take place in the ligaments, joints, disc material, and bones. While many of these occur naturally as we age, professionals are finding degenerative problems appearing in younger populations in recent years. The sooner corrective action is sought and undertaken, the sooner the cycle of pain and dysfunction can be reversed. However, constant vigilance must become the buzzword. It’s just too easy to slip back into poor postural habits, eventually undoing correctional work.