Spinal cord Flashcards
What is the role of the zygapophysial joints?
control the vertebral columns flexibility
What happens to the size of the vertebral body as it descends the spinal column?
Increases in size to support weight of the body
What components make up the vertebral arch?
spinous process, lamina, pedicle
Where are the pedicles found?
project posteriorly from the body to meet 2 broad, flat plates of bone called lamina
What forms the walls of the vertebral foramen?
The vertebral arch (lamina and pedicle) and the posterior surface of the vertebral body
The succession of vertebral foramina in the articulated vertebral column forms the…?
vertebral canal (spinal canal)
What processes interact to form the zygapophysial joint?
Inferior articular process and superior articular process
Describe the characteristics of cervical vertebrae?
- smallest in size, as bear the least weight
- oval transverse foramen in the transverse process
- bifid spinous process except C1 and C7
- IV discs are thinner than inferior regions but relatively thick compared to size of cervical vertebral bodies
- nearly horizontal orientation of the articular facets –> greatest range of movment of all vertebral regions
What runs through the transverse foramen in the cervical region of the spine, and what is the exception to the rule?
vertebral arteries and veins except those in C7, which transmit only small accessory veins
foramen in C7 are smaller and sometimes absent
What is the purpose of the anterior and posterior tubercles in the cervical vertebrae?
tubercles provide attachment for a laterally placed group of cervical muscles (levator scapulae and scalenes)
In summary describe the characteristics of the cervical vertebrae
body - small
vertebral foramen - large and triangular
transverse processes - transverse foramina and anterior and posterior tubercles, vertebral arteries and accompanying venous and sympathetic plexuses pass through transverse foramen except C7 which transmits only small accessory vertebral veins
articular processes - superior facets directed superioposteriorly; inferior facets directed inferioanteriorly
What are the names of C1 and C2 vertebrae?
Atlas and axis
Describe the physical characteristics of of Atlas?
no vertebral body and no spinous process
- has paired lateral passes which bear the weight of the cranium
- transverse processes of the atlas arise from the lateral masses, causing them to be more laterally placed than those of the inferior vertebrae
- has a facet and foramen for the dens of C2
Describe the characteristics of axis
-strongest of the cervical vertebrae.
- C1 carrying the cranium, rotates on C2 .e.g. when a person says no.
(atlanto-axial)
- Axis has 2 large, flat bearing surfaces - the superior articular facets, on which the axis rotates
- has the dens which projects superiorly from its body
- dens lies anterior to the spinal cord
How is the dens held in position?
held in position against the posterior aspect of the anterior arch of the atlas by the transverse ligament of the atlas
Describe the characteristics of the thoracic vertebrae
- provide attachments for the ribs
- costal facets
- heart shaped vertebral body
- one or 2 costal facets for articulation with the head of rib
- vertebral foramen: circular and smaller than those of cervical and lumbar vertebrae
Describe the characteristics of the lumbar vertebrae
Body is massive and kidney shaped
vertebral foramen are triangular and larger than thoracic but smaller than in cervical
- long slender transverse process
What is vertebral body osteoporosis?
Common metabolic disease
- osteoporosis results from a net demineralisation of the bones due to imblance between calcium resorption and deposition
- quality of bone is reduced and atrophy of skeletal tissue occurs
- osteoporosis most commonly affects neck of femur, bodies of vertebrae, metacarpals and radius
- bones brittle and subject to fracture
- osteoporosis especially affects the horizontal trabeculae of the spongy bone of the vertebral body
- most common in thoracic vertebrae
Where are you most likely to get a dislocation in the spinal vertebrae?
Cervical vertebrae due to their more horizontally oriented articular facets
cervical vertebrae as a result are less tightly interlocked
Describe the fracture and dislocation of axis
C1 is a bony ring, with 2 wedge shaped lateral masses
- vertical forces compressing the lateral masses between the occipital condyles and the axis drive them apart
What is lumbar spinal stenosis?
stenoic (narrowed) vertebral foramen in one or more lumbar vertebrae
- can be hereditary or due to age related changes e.g. IV disc bulgin
- lumbar spinal nerves increase in size as the vertebral column descends but the IV foramina decrease in size
- stenosis can cause compression of spinal nerve
Describe the effect of ageing on vertebrae
Between birth and age 5, body of a typical lumbar vertebra increases in height 3 fold. Between ages 5-13 increases another 45%. Growth completed age 25.
During middle and older age there is an overall decrease in bone density and strength particularly centrally within the vertebral body
- IVD become increasing convex
- osteophytes develop around the margins of the vertebral body
Where are the ligametum flavum found?
Lamina of adjacent vertebral arches are joined by broad elastic tissue - ligamentum flavum
- thickest in the lumbar region
Where are the interspinous ligaments found?
interspinous ligaments connect adjoining spinous processes
