Musculature around the Sacroiliac Joint. Permission Joseph E. Muscolino. Manual Therapy for the Low Back and Pelvis - A Clinical Orthopedic Approach (2013).

Five Muscles of Sacroiliac Stabilization – Part 1 – Piriformis

Even when the original reason for the sacroiliac stabilization is valid, often the human body overdoes it and tightens the musculature excessively and/or keeps it tight long after it needs to be, so the musculature becomes stuck in a chronic pattern of hypertonicity.

Posterior views of the deep lateral rotator group (including the piriformis)

Muscles of the Pelvis

Pelvic musculature: 1. cross the LS joint onto the trunk 2. cross the hip joint onto the thigh/leg 3. pelvic floor muscles located wholly within the pelvis