ABSTRACT
The abdominal mechanism, utilizing intraabdominal pressure, has been described and numericized. Simulations show that the lumbodorsal fascia under control of the abdominal muscles contributes to reduce the stress at the intervertebral joint. The musculature of the lumbar spine is of primary importance in the control of the efficiency of the spinal mechanism. The system of loading, which results in observable physiologic response, maintains the compressive load at virtually 90 degrees at the bisector of the disc for all weights and all angles of forward flexion.
Subject(s)
Abdominal Muscles/physiology , Spine/physiology , Fascia/physiology , Humans , Joints/physiology , Ligaments/physiology , Models, Biological , Stress, MechanicalABSTRACT
A sagittal plane mathematical model for the cervical spine has been used to simulate the neck's response to loads due to high acceleration. The model is capable of simulating the muscular response of the cervical spine and the stress distribution between the joint levels. In order to obtain conservative estimates of the maximum acceleration that the neck can support, the neck was simulated using the assumption that the inertial load is supported primarily by the muscles. It was found that accelerations of up to 30 g can be supported with the appropriate posture and direction of acceleration. Estimates were also obtained using experimental results to approximate the role that the ligaments of the spine play in supporting the load. It was found that accelerations of up to 40 g can be supported for the appropriate posture and acceleration direction.
