Transcript Pelvis Function in Gait

Pelvis Function in Gait

Introduction to Gait

• Range of Motion (ROM) and muscle activations during gait will be discussed joint by joint.

• Pelvis rotation occurs in the horizontal plane around a vertical axis of rotation through the stance limb's hip joint.

• Various cycles of gait will highlight the pelvis's activity during movement.

Movement in the Sagittal Plane

• Described as short arc rotations in anterior and posterior directions about a mediolateral axis through the hip joints.

• Direction of pelvic tilt is determined by the iliac crests' movement.

• Neutral pelvic position (0 degrees) is the relaxed stance of the pelvis.

• Both iliac crests act as a rigid structure, moving in unison.

• Normal speed gait involves approximately 2 to 4 degrees of anterior and posterior pelvic tilt.

• Kinematics primarily occur at the hip joints, though it's depicted as separate pelvic movement.

Gait Cycle Overview

• The gait cycle is illustrated from right heel contact to the next right heel contact.

• Increased pelvic tilting correlates with faster ambulation, which also lengthens functional limb length and step length.

• Passive and active forces from the hip joint capsule and hip musculature dictate the sagittal plane pelvic tilt.

Pathologic Situations

• Individuals with significant hip flexion contractures may show exaggerated anterior pelvic tilt, particularly between 30% to 60% of the gait cycle.

• Excessive anterior pelvic tilt compensates for limited hip extension and is often associated with increased lumbar lordosis.

Frontal Plane Motion

• Observed best from front or back as the iliac crests rise and fall relative to the horizontal plane.

• The pelvis rotates 10 to 15 degrees due to pelvic on femoral adduction and abduction.

• During right lower extremity weight acceptance, the left iliac crest drops due to pelvic on femoral adduction.

• Eccentric activation of the right hip abductors controls the downward motion of the left iliac crest.

• From 20% to 60% of the gait cycle, the left iliac crest is elevated by concentric activation of the right hip abductors and trunk shift to the right.

Horizontal Plane Rotation

• The pelvis rotates around a vertical axis through the stance limb's hip joint during walking.

• Right heel contact sees the right Anterior Superior Iliac Spine (ASIS) positioned forward compared to the left ASIS.

• Internal (counterclockwise) rotation occurs during the first 15% to 20% of the gait cycle; external (clockwise) rotation follows during the rest of the stance phase.

• At right toe off, the right ASIS is positioned behind the left, and during the swing of the right lower extremity, it progressively moves forward.

• Total pelvic rotation ranges from three to four degrees in each direction.

Clinical Relevance

• The initiation and control of global pronation of the lower extremity during early stance phases of walking and running are essential concerns.

• It is assumed that internal rotation occurs as a response to overall foot pronation.

• Pronation leads to tibial internal rotation, which results in femoral internal rotation, suggesting a bottom-up kinesiological control.

• This understanding underpins the prescription of specialized footwear and orthotic devices for individuals experiencing excessive global pronation.