Question Answer What kind of joint is the Lumbosacral joint? Secondary Cartilaginous IV Joint.The zygapophyseal joints are synovial joints. What kind of Joint is the Sacroiliac Joint? Synovial joint What structures articulate within the sacroiliac joint? The auricular surface of the sacrum and the ileum Is the sacroiliac Joint a weight bearing joint? Yes What kind of joint is the pubic symphysis? Secondary cartilaginous joint b/w pubic bones What kind of curvature would you expect to find in the Lumbar spine and the sacral spine? Lumbar = lordosisSacral = kyphosis How are the articular processes arranged in the Lumbar spine, the sacral spine, and the lumbosacral join? Lumbar spine = MediallySacral spine = laterallyLumbosacral joint = laterally Why is the lumbosacral zygapophyseal joint arranged the way it is? To prevent the anterior 'slip' of the spinal cord superior to the sacral spine. What ligaments hold the lumbosacral joint together? Anterior longitudinal ligamentPosterior longitudinal ligamentLigamentum flavumintertransverse ligamentsinterspinous ligaments Is the ilium said to have an auricular surface? Yes What ligaments stabilize the sacroiliac ligament? Anterior sacroiliac ligamentPosterior sacroiliac ligamentInterosseus ligamentsSacrotuberous ligamentSacrospinous ligament How do the sacrotuberous and sacrospinous ligaments protect the sacroiliac joint? They prevent too much nutation. What muscle originates at the sacrotuberous ligamen and other originst? Gluteus maximus What structures form the greater sciatic foramen? The ischial spine and the sacrospinous ligament inferiorly,the sacrotuberous ligament posteromedially, anterolaterally by the greater sciatic notch of the ilium. What structures pass through the greater sciatic foramen? The piriformis and the nerves that pass above it and below it.(sciatic, sup. gluteal, inf. gluteal, post. Femoral cutaneous nerve) What is nutation and counternutation? Nutation is forward tilt of the spine and counternutation is the opposite Describe the reverse keystone effect. The reverse keystone effect is the effect where the sacrum is held into the ilium via interosseous ligaments and as a result the ilium bones are drawn together and hold the sacrum in place. .