Spinal Cord and Spinal Nerves Flashcards
How many cervical spinal nerves are there?
8
How many thoracic spinal nerves are there?
12
How many lumbar spinal nerves are there?
5
How many sacral spinal nerves are there?
5
How many coccygeal spinal nerves are there?
1
Which region of the spinal cord has a different number of spinal nerves to vertebrae?
cervical (7 vertebrae, 8 spinal segments)
How many spinal nerves is given off by each spinal segment?
a pair
Where does the C1 spinal segment leave the spinal cord?
below the base of the skull and above the C1 vertebra
Are cervical spinal nerves above or below their corresponding vertebra?
above
Do thoracic spinal nerves leave from above or below their corresponding vertebra?
below
Do lumbar spinal nerves leave from above or below their corresponding vertebra?
below
Do sacral spinal nerves leave from above or below their corresponding vertebra?
below
Does the coccygeal spinal nerve leave from above or below its corresponding vertebra?
below
Why do we have the cervical enlargement?
to allow for the brachial plexus
Why do we have the lumbar enlargement?
to accommodate the sciatic nerve leaving
What type of information do dorsal rootlets carry?
sensory information (passing into specific segment of spinal cord)
What and where is the conus medullaris?
the inferior tip of the spinal cord, about level of L1-L2
What is the cauda equine?
dorsal and ventral rootlets of lower lumbar, sacral and coccygeal segmental spinal nerves
What is the filum terminale a remenance of ?
development of the spinal cord
What is the filum terminale made of?
pia matter
What is different about dura matter in the spinal cord and brain?
in spinal cord, there is no periosteal layer
How does CSF enter the subarachnoid space?
lateral and median apetures
What space prevents there being two dural layers of the spinal cord?
epidural layer of subcut fat
What is a denticulate ligament?
extensions of pia matter that extend from the lateral aspect of the spinal cord to the lateral wall of the vertebral canal
What is the function of denticulate ligaments?
To stabilise the spinal cord
What is a ganglion?
collection of cell bodies in the peripheral nerve system
Why is L3-L4 a good space to do a lumbar puncture?
no spinal cord - rootlets of cauda equine will move out of the way
How are there sacral/coccygeal rootlets if there is no spinal cord below L2?
Because in a foetus the spinal cord was the full length of the vertebral column and gives off the nerve roots then, however grows slower than the vertebral canal so ends up shorter
At birth, what level does the conus medullaris lie?
about L3
What does grey matter contain?
Cell bodies
What does white matter contain?
Tracts (axons)
What does the lateral grey horn lead to?
ANS
What fibres run in the dorsal root of the spinal nerve?
somatic and visceral sensory
What fibres run in the ventral root of the spinal nerve?
somatic and visceral motor
How many dorsal columns are on each side of the midline above and below T6?
2 above (gracile and cuneate fascicles) and 1 below
Where are there enlagrments in ventral grey horn on the spinal cord ?
where motor fibres to limb arise (cervical and lumbrosacral enlargements)
