The sacroiliac joint
Synonym: ISG, sacroiliac joint, sacroiliac-iliac joint, short sacroiliac joint. The sacroiliac joint represents the articulated connection between the sacrum (lat. Os sacrum) and the ilium (lat.
Os ilium). Structure: This is ISG is an amphiarthrosis, which means a joint in which there is almost no movement. The joint surfaces (lat.
Ligamenta sacroiliaca interossea) are firmly connected by fibrous cartilage. Ligamentous securing is ensured by the following ligaments: Ligamenta sacroiliaca anteriora, ligamenta sacroiliaca posteriora et interossea, ligamentum iliolumbale, ligamentum sacrotuberale and sacrospinale. The movements in the sacral joint are called nutation and contranutation.
This means that a minimal movement in the lateral plane is possible. This movement is particularly important for the birth process, since nutation, together with the expansion of the pubic symphysis, widens the pelvic ring. This ensures the passage of the newborn’s head.
Diseases of the sacroiliac joint are diverse and range from osteoarthritis, through violent trauma, which can lead to fractures, to ankylosing spondylitis, which is a congenital disease that often affects the sacroiliac joint. Acute or chronic inflammation of the ISG is also possible and should be treated accordingly.
