BIOL 115 Lecture Notes - Lecture 11: Abdominal Cavity, Psoas Major Muscle, Abdominal External Oblique Muscle
Document Summary
Iliocostalis lumborum- imparts compressive and posterior shear force and is a dynamic counterforce to anterior shear at ls. Right and left separated by linea alba. Unilateral flexion and ipsilateral trunk rotation. Bilateral compression of abdominal cavity and increased tension in. Psoas acts to disperse stress created by iliacus. Iliacus acting alone- causes pelvic rotation and ipsilateral side bending. Stabilizer- eccentric control of sb and frontal plane balancer for swing leg. Resist flexion and anterior shear with forward bending. Limits excessive small movements between intervertebral junctions. Creates firm base for muscles to move limbs. Lumbar muscles- back extensors generally capable of greater torque potential than flexors (counteract gravity and flexion moment of trunk) Extrinsic trunk stabilizers intervertebral junctions at a time. Stabilize spine by controlling precise alignment and stiffness of a few. Stabilize trunk by creating semi-rigid link between cranium, spinal column, pelvis. Generate significant torque for trunk and hips. Erector spinae (psoas major, quadratus lumborum, hip muscles connecting.
