Pelvic Incidence: The Great Biomechanical Effort

Area of Science:

• Orthopedics
• Biomechanical Engineering
• Radiology

Background:

• Medical education often separates the spine and pelvis, neglecting their interconnectedness.
• The pelvis plays a critical role in maintaining spino-pelvic alignment.
• Understanding pelvic morphology is essential for analyzing spinal alignment.

Purpose of the Study:

• To highlight the critical role of the pelvis in spino-pelvic alignment.
• To introduce and explain the pelvic incidence angle (PI) as a measure of pelvic morphology.
• To establish the relationship between PI and spinal sagittal curvature.

Main Methods:

• Reviewing established concepts of spino-pelvic anatomy.
• Introducing the 3-dimensional pelvic vertebra concept.
• Defining the pelvic incidence angle (PI) based on specific anatomical landmarks.

Main Results:

• The pelvis is integral to spinal alignment, not a distinct entity.
• The pelvic incidence angle (PI) quantifies pelvic morphology.
• PI is theorized to regulate the sagittal curvature of the spine.

Conclusions:

• Simultaneous analysis of pelvic morphology and spinal alignment is necessary.
• The pelvic incidence angle is a key metric for understanding spino-pelvic relationships.
• This approach reframes the understanding of spinal biomechanics.