| A | B |
|---|
| the vertebral column (spine) acts as a... | modified elastic rod providing support and flexibility |
| there are ... vertebrae in the vertebral column | 33 |
| ...vertebrae are moveable and contribute to... | 24, joint movements |
| the motion segment of the spine is the ....of the spine and consists of | functional unit of the spine, two adjacent verterae and the disc that separates them |
| spine curves | cervical spine is an inward/concave curve lordosis. thoracid sine is an outward/convex curve (kyphosis), lumbar spine has another inward/concave curve (sway back) |
| anterior part of movement segement | contains the two vertebral bodies, the iner-vertebral disc and the anterior posterior longitudinal ligaments |
| invertabral disc | shock absorbers for compression |
| vertebral body | thickest part, withstand compression/thicker in front where most compression exists. covered with hyaline cartilage |
| the two vertebral bodies and the disc of the anterior portion of movement segment form a | form a cartilaginous joint |
| each vertebral body consists of | cancellous tissue surrounded by a thick cortical layer |
| the vertebral body has a ...to facilitate the... | a raised rim to facilitate the attachment of the disc, muscles and ligaments |
| the invertebral disc ...the two bodies which allows.. | separates, movement between the bodies and resists compressive, torsional and bending forces |
| role of the disc is to | bear and distribute loads and restrain excessive motion in the vertebral segment |
| the load transmitted via the discs distributes... | stress uniformly over the vertebral end plates |
| each dics consists of the ... | nucleus pulposus and annulus fibrosis |
| nucleous pulposus | a gel-like material (80% water and 20% collagen) in central portion of the disc. creates a fluid mass that is always under pressure thus exerting a preload on the disc. well suited to withstand compressive forces. during the day, the water conctent of the disc is reduced due to compressive forces (spinal column reduces by about 15 to 35mm) |
| the nucleus pulposus is surround by.. | rings of fibrous tissue called the annulus fibrosus |
| the fibers of the annulus run..but are oriented...each alternate layer runs...when rotation is applied... | run parallel in concentric layers but are oriented diagonally at 45 degrees to 65 degrees to the vertebral body. each alternate layer runs perpendicular to the previous layer creating a crisscross pattern. when rotation is applied to the disc, half the fibrs tighten while the fibers runnin in the other direction will be loose |
| the fiber direction in the annulus limit...and | rotational and shearing motions between the vertebrae |
| fibers in the annulus are made up of ... | 50-60% collagen to provide tensile strength |
| collagen is ...in response to changes in loading | remodeled |
| thicker annulus fibers in the..and thinner fibers in the | anterior disc, posterior |
| discs function ... | hydrostatically (flexible under low loads and stiff under high loads) by absorbing water |
| pressure in the nucleus pulposus....with compressive loads | increases linearly. the nucleus exerts a pressure to absorb water |
| two weak points where disc injury occurs | cartilage and plates to which the discs are attached, posterior annulus is thinner and not attached as firmly as other portion of the disc |
| longitudinal ligaments | run from the base of the skull to the sacrum |
| anterior longitudinal ligament | attaches to the anterior disc and the vetebral bodies (limits hyperextension and restrains forward movement of one vetebrea over anohter) |
| posterior longitudinal ligament | runs down the posterior surface inside the spinal canal (resists flexion) |
| posterior portion of the movement segment | contains the neural arches, intervertebral joints, transverse and spinous processes and ligamens |
| there are...formed by the articulating facets on the supper and lower sides of the vertebrae | two synovial joints |
| the superior facets are...and fit into the.. | concave, into the interior facets of the adjacent vertebrae |
| the articulating facets are oreinted...in the regions of the sine | differently |
| there are ...ligaments that support the posterior portion of the vertebral segment | 5 |
| ligamentum flavum | connects adjacent vertebral arches longitudinally (elongates in trunk flexion and contracts in extension) |
| suprasinous and interspinous ligaments | but run from spinous process to spinous process (resists both shear and forward bending of the spine) |
| intertransverse ligaments | connect transverse process to transverse process (resists lateral bending of the trunk) |
