31 Questions
What forms a passive segment in the vertical plane?
The vertebra itself
What is responsible for the movements of the vertebral spine?
The mobile segment
What is the function of the pedicles?
To form a functional link between the anterior and posterior pillars
What is the role of the intervertebral disc in the vertebral motion segment?
To cushion axial compression forces passively
What are the degrees of freedom (DoF) in a joint?
6
What type of movement is possible at the interbody joints?
Gliming, distraction, compression, and rotation
What is the role of the paravertebral muscles in the vertebral motion segment?
To cushion axial compression forces indirectly and actively
What type of stress is the vertebral column subjected to during normal functional activities?
Axial compression, tension, bending, torsion, and shear stress
What is the reason for the expression of fluid from the nucleus pulposus and the annulus fibrosus?
Due to sustained compressive loading
What is the structure of each vertebra?
Trabecular structure involving the body and the arch
What happens when the compressive forces are decreased?
The disk imbibes fluid back from the vertebral body
Why is a person taller in the morning than in the evening?
Due to the disk imbibing fluid back from the vertebral body
What is the stiffness of the vertebral column?
The column's ability to resist an applied load
What determines the vertebral column's ability to resist loads?
The type, duration, and rate of loading, the person's age and posture, the condition and properties of the structural elements, and the integrity of the nervous system
During forward flexion, which structures are subjected to tension?
Anterior structures
What provides stability in flexion?
Tensile forces by collagen fibers in the posterior outer anulus fibrosus
During extension, which structures are subjected to tension?
Anterior structures
What provides resistance to extension?
Zygapophyseal joint capsules and anterior longitudinal ligament
During lateral bending, which side of the disk is compressed?
Ipsilateral side
What helps to provide stability during lateral bending?
Outer fibers of the contralateral side of the disk and the contralateral intertransverse ligament
What results from prolonged forces with creep loading?
Increased compressive and bending forces on the neural arch and ligaments
What happens to the load on the spine when there are prolonged compressive forces?
It shifts from the nucleus pulposus to the annulus fibrosus
What is the result of the increased load on the annulus fibrosus?
Buckling or prolapse of the annulus fibrosus
What is the effect of creep on the supporting structures?
It causes elongation of the structures
What type of forces are created during axial rotation?
Torsional forces
Where is the highest torsional stiffness found?
At the thoracolumbar junction
What structures provide torsional stiffness?
The outer layers of both the vertebral bodies and intervertebral disks
How do the annulus fibrosus fibers resist rotation?
Half the fibers resist clockwise, and the other half resist counterclockwise rotation
What is the most effective structure in the lumbar region for resisting torsion?
The annulus fibrosus
What increases the risk of rupture of the disk fibers?
Combination of torsion, heavy axial compression, and bending
What is the result of the coupled motions?
Torsional forces
Learn about the mobile and passive segments in the vertical plane of the vertebral spine, including bony and ligamentous structures, intervertebral discs, and facet joints. Understand the mobility of the active segment and its role in spinal movements.
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