The Vertebral Column And Segmental Innervation Of The Limbs Flashcards
In the cervical spinal cord, where do spinal nerves emerge?
Spinal nerves emerge through foremen superior to the corresponding vertebral levels
In the non-cervical spinal cord, where do spinal nerves emerge?
Spinal nerves emerge through foremen inferior to the corresponding vertebral levels
How many bones form the vertebral column?
33
What are the functions of the vertebral column?
Provides centre of gravity of body
Provides attachments for bones (both axial and appendicular)
Supports head and ribs, anchors axial skeleton
Provides attachments for trunk muscles (for posture)
Protection and passage of the spinal cord- allows segmental nerves to leave or join the cord at specific points to supply their targets
Describe the foetal vertebral column
Only has Primary Curvature - figure of C shape, concave anteriorly.
This is retained throughout life in the thoracic and sacral parts.
What is kyphosis?
Exaggerated primary curvature of the vertebral column
Describe the development of the vertebral column from a foetus to a young adult
The c-shaped column opens up to elongate.
1st posterior concavity (cervical) forms when the child lifts its head, 2nd posterior concavity (lumbar) spine opens up when child begins to crawl and walk.
What is lordosis?
Exaggerated secondary curvature
Describe the vertebral column in a young adult
Has 4 distinct curvatures (figure of s shape, sinusoidal profile)
Has 2 anterior concavities which are continuations of primary curvature, in the thoracic and sacral sections.
Has 2 posterior concavities = secondary curvatures in the cervical and lumbar sections
Describe the changes that occur to the vertebral column in old age?
Secondary curvature starts to disappear, vertebral column returns to its original shape in foetus: full continuous primary curvature re establishes, vertebral column closes up again.
How many discrete single vertebrae and fused vertebrae are there?
24 discrete single vertebrae capable of individual movement
9 vertebrae are fused to give 2 innominate structures, 5= sacrum and 4= coccyx
Where does the spinal cord start and end?
Starts where the medulla of the brain ends at the Conus Medullaris.
Ends where it tapers into the Filum Terminale ligament at about L2/L3.
What parts make up the neural/vertebral arch?
Spinous process in centre, transverse processes on the sides.
Lamina = area between transverse and spinous processes
Pedicle = area between body and transfers processes
Articulate processes at junctions of pedicle and Lamina. 1 above and 1 below on each side, strengthened by liamentum flavum.
What are the 2 main parts of a Vertebra?
The Vertebral Body and the Vertebral (neural) Arch
What are facet joints?
The joints between the neural arches, prevent anterior displacements of all the vertebrae.
Describe the structure of intervertebral discs
Peripheral region = the Annulus Fibrosus, made up of annular bands with varying orientations (outer bands are collagenous and inner bands are fibro-cartilaginous)
Central region = the Nucleus Pulposus, jelly like with high osmotic pressure to act as a water reservoir for the disc. Changes in size throughout the day and with age. Centrally located in infant,mposterior in adults.
Where are intervertebral discs found?
Separating successive vertebrae from C2 to S1
What are the functions of intervertebral discs?
They are responsible for the flexibility of the vertebral column
Act as a shock absorber
They are wedge shaped in the lumbar and thoracic levels (thickest anteriorly) which accounts for the secondary curvature of the spine
What is a slipped disc?
When the Nucleus Pulposus herniates through the the Annulus Fibrosus, leading to compression of the spinal segmental nerves.