BIOL 115 Lecture Notes - Lecture 9: Iliolumbar Ligament, Angle, Facet Joint
Document Summary
Concave superior articular facet face medial to posteromedial. Convex inferior articular facet face lateral to anterolateral. L5-s1 in frontal plane (provide significant ap stability) Increases diameter of intervertebral foramen by 19% and vertebral canal by 11% Superior articular facets glide anterosuperior on inferior articular facet. Compressive forces of body weight shifted away from facets, toward the vertebral bodies and disc. Anterior disc compressed and tension in posterior disc. In extreme flx- small surface area contact of facets. Initiated by abdominal muscles and vertebral portion of psoas. In full flx- erector spinae become inactive. Flx relaxation phenomena- erector group does eccentric contraction during fb with erector group does concentric contraction during bb. Features- load and surface contact increases at facet joints and diameter of intervertebral foramina reduces 11% and volume of vertebral canal decreases 15% Superior articular facet glide inferiorly on inferior articular facet.
