Spinal cord function and dysfunction Flashcards
Recall the segments of the spinal cord
31 total
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
How do nerves exit the spinal cord?
Through intervertebral foramina
Recall the relationship between each spinal nerve and its point of exit from the spinal cord
- C1-C7 emerge above their corresponding vertebrae
- C8 comes out below C7
- T1 onwards emerge below their corresponding vertebra
What is the white matter of the spinal cord made up of?
Ascending and descending tracts
Within the nervous system, what words replace the anatomical descriptions of “superior” and “inferior”?
Superior = rostral
Inferior = caudal
What is the grey matter of the spinal cord made up of?
Neuronal cell bodies
What are the main sensory and motor tracts of the spinal cord?
Sensory - spinothalamic and dorsal columns
Motor - corticospinal
Summarise how sensory information is sent to the brain.
3 neurons (primary, secondary, tertiary) are needed to trasnmit sensory information to the cerebral cortex
Where 1st order synapses with 2nd order = crossing to other side of spinal cord
What is the consequence of a disruption in brain influence over reflex action?
Spasticity due to lack of higher control
What feature is unique to the thoracic segments of the spinal cord?
Intermediate lateral horn
Describe the distribution of sensory and motor fibres in the spinal cord?
Motor = ventral
Sensory = dorsal
Both = lateral
Name the dorsal and ventral fissures in each spinal segment and recall which is wider
Dorsal = posterior median sulcus
Ventral = anterior median fissure (wider)
These divide the anterior and posterior surfaces of the spinal cord into two halves.
At which vertebral level does the spinal cord end?
L2
Recall the regions of enlarged spinal cord
For upper limbs: cervical enlargement: C3–> T1
For lower limbs: lumbar enlargementL L1–> S3
Where are the motor neuronal cell bodies located?
Grey matter
Where are herniated discs most likely to occur, and why?
L5/S1
Discs are present posteriorly but not anteriorly
Which 2 layers of the meninges extend past the end of the spinal cord?
Dura and arachoid
What part of the spinal cord is most amenable to CSF removal and why?
Between L2 and S2 as there is a large volume of CSF and some floating neurons but no spinal cord
Recall the 3 factors affecting the severity of a spinal cord lesion
- Amount of neural tissue lost
- Vertical level - the higher the lesion the greater the disability
- Transverse plane
Recall the expected pathology following an injury to the lateral corticospinal tract.
- Spinal shock - loss of reflex activity below the lesion lastinc for days or weeks= flaccid paralysis
- Return of reflexes leading to hyperreflexia and/or spasticity = rigid paralysis
What is a spinal segment?
A portion of the spinal cord which gives rise to spinal nerves