The sacroiliac joint is where the upper body meets the lower body. It is the center of motion, the center of shock absorption, and the center of power transfer between the upper and lower body. When we talk about core, this is what we are talking about, the sacroiliac joint, not the lumbar spine.

In this section, I display how the sacroiliac joint functions as the core of our musculoskeletal system, with various views of the sacroiliac joint.

I also compare the ligamentous suspension of the sacrum (i.e. tensegrity) to the popular keystone concept, and discuss the discrepancies between them in, as described in published in books and peer-reviewed research by leading anatomists.

I have developed illustrations and animated videos to demonstrate the pelvic structures and their movements. In the section on Muscular Adaptations , I use videos to illustrate how individual muscles create these movements.

The goal is to tie the entire musculoskeletal system into a functioning whole. By visualizing the integration of the structure and soft tissue, we can understand how our body moves normally and how it reacts to injury and, with this knowledge, develop proper strategies to both improve performance and treat injuries.