Spinal Cord Flashcards
What are the anterior boundaries of the vertebral canal?
vertebral bodies
intervertebral discs
posterior longitudinal ligament
What are the lateral boundaries of the vertebral canal?
Pedicles - notches
intervertebral foramina
What are the posterior boundaries of the vertebral canal?
laminae
facet (zygapophyseal) joint
ligamentum flavum
spinous processes
The spinal cord is protected by?
Vertebrae
Ligaments
Meninges
CFS cushioning
How many spinal nerves are there?
31 pairs
8 Cervical nerves C1 – C8
12 Thoracic T1 –T12
5 Lumbar L1 – L5
5 Sacral S1 – S5
1 Coccygeal Co
Spinal nerves consist of?
- axons of sensory neurones from an area of skin (dermatome)
- axons of motor neurones to a group of muscles that share a function (myotome)
- axons of sympathetic neurones to structures in the body wall that control body temperature
Where do you get a sample of CSF?
can be sampled by inserting a needle into subarachnoid space below the Conus Medullaris
Compare the course of the spinal cord in adults to that of neonates?
Begins at the foramen magnum of the skull as the continuation of the brain stem
In adults
foramen magnum > disc between L1/L2
> In adults the spinal cord occupies the upper 2/3rds of the canal
In neonates
foramen magnum > approximately L3
Ends as the filum terminale attached to the sacral vertebral bodies
Where are the spinal cord enlargements?
- Cervical expansion
- between C5 and T1
- due to the brachial plexus - Lumbosacral expansion
- L1 and S3
- due to the lumbar plexus - Conus medullaris
- most inferior part of the cord before it narrows to form the filum terminale
What is the lumbar cistern?
Subarachnoid space caudal to the end of the spinal cord
> CSF
> Roots of lumbar and sacral nerves
Name and describe the structural components of the spinal cord?
- Anterior/Ventral median fissure
- Deep
- CT of pia mater
- Anterior spinal artery and its branches - Posterior/Dorsal median fissure
- Shallow midline fissure - Central canal
- CSF very small
- Lined by ependyma cells
- In brain this space is expanded to form ventricles
Slight grooves where the nerve rootlets arise form the cord
What is the white matter of the spinal cord?
Tracts of axons
Myelinated axons
What is the grey matter of the spinal cord?
nerve cell bodies
What is the Bell-Magendie Law?
Afferent fibers enter spinal cord through dorsal root spinal verves
Motor and other efferent fibers leave through ventral roots
What are motor neurons?
- Excited or inhibited by impulses
- Impulse originate at various levels of brain
- Medulla to cerebral cortex
Describe the white matter of the spinal cord?
- Myelinated – white
- Have nerve fibres, neuroglia, blood vessels
- Divided into 3 faniculi/columns
1. Anterior/Ventral White Faniculus
2. Lateral White Faniculus
3. Posterior/Dorsal White Faniculus
> Gracile Fasciculus : Present throughout the length of the cord
> Cuneate Fasciculus : Above mid-thoracic level - Axons decussate in ventral white commissure
- Dorsolateral tract/Tract of Lissauer
> Occupies space between apex of dorsal horn and surface of cord
Describe the gray matter of the spinal cord?
- Gray mater H-shaped
- Central gray matter indicate the number of neurons
- Anterior/Ventral Gray Horn
- Posterior/Dorsal Gray Horn
- Intermediate zone joining two horns
- Lateral Gray Horn (in thoracic and lumbar regions)
- Commissure – joining two sides
Name the 3 types of neurons in gray matter?
- Motor cells
- Are in ventral horn
- Supply the skeletal musculature - Tract cells
- Mainly located in dorsal horn
- Constitute ascending fasciculi of white matter - Interneurons
- Cells involved in local circuit