lesson 25 Flashcards
what is the central nervous system consist of ?
brain and spinal cord
what are the different segments consisting in the spinal cord?
8 cervical segments
12 thoracic segments
5 lumbar segments
5 sacral segments
1 coccygeal segment
what are the spinal nerves? and how many are located in each segment of the spinal cord?
spinal nerves are nerves sending signals between the CNS and the body and they belong to the peripheral
- 8 bilateral pairs of spinal nerves
- 12 bilateral pairs of spinal nerves
- 5 bilateral pairs of spinal nerves
- 1 bilateral pair of spinal nerves
what are afferent and efferent fibers?
afferent (sensory) fibers - getting affected
(transmit information from the sensory information to the central nervous system ex. temp, pain heat)
efferent (motor) fibres- effecting something
(away from the nervous system to muscles and glands)
what are the two enlargements in the spinal cord?
cervical enlargement
lumbosacral enlargement
what arises from the enlargements found in the spinal cord? what is found in the cervical enlargement and what is found in the lumbosacral enlargement
nerve plexus
cervical enlargement - brachial plexus
lumbosacral enlargement- lumbosacral plexus
what is the duty of the brachial plexus?
Bring information too and from the upper limb
What is the duty of the of the lumbosacral plexus?
bring information too and from the lower limbs
what is a laminectomy?
where we cut the laminae of the vertebrae or the vertebral column,
cervical to lumbar
-remove spinous processes and medial stuff
-this reveals the spinal cord, etc.
in adults where does the spinal cord end? and what is found after L2?
it ends at before the L2 mark,
and below the L2 is spinal nerves
during development where was the spinal cord located?
During development, the spinal cord lived within the entire region of the vertebral and sacral canal.
- the segments aligned with the vertebrae, and spinal nerves expired the vertebral canal directly lateral from the segment they arose from.
what is the reason that our spinal cord when we are older does not look the same as when we were younger?
The vertebral column grows faster than the spinal cord
- caused the lengthening of spinal nerves, and the spinal cord only reaches L2
- as we travel inferiorly of the vertebral column, the length of spinal nerves increases progressively
- and the distance between the origin of the spinal nerves and its point of exit also increases
-lumbar and sacral spinal nerves are the longest
what is the bundle of spinal nerve roots called at the bottom of the spine?
cauda equina
which vertebral level is this taken from?
inferior to L2
-L3,L4,L5
-lumbar vertebrae but also the spinal cord is not present within the vertebral canal and we only see the cauda equina
what structures form the boundaries of the intervertebral foramina?
- vertebral body
-pedicle
-superior articular process
-inferior articular process
-intervertebral disc
What is important to note about the c1-c7 spinal nerves found in the spinal cord?
all the spinal nerves from c1-c7 exit superior to their designated vertebrae
But the c1-c7 spinal nerves with the same ID as vertebrae form the inferior margin of vertebral foramina the spinal nerve exits.
What is important about the C8-co1 spinal nerves?
They have the same ID as the vertebrae forming the superior margin of Intervertebral foramina that the spinal nerve exits
- they are going to exit inferior to the vertebrae with the same name
what stems out from the spinal vertebrae (rootlets roots)?
we have rootlets, then roots then spinal nerve then rami
What significance of the spinal nerve?
The spinal nerve is a mixture of the afferent and efferent (motor and sensory fibers)
-anything distal to that is also motor and sensory
what types of results would happen after there have been injuries to certain parts of the spinal nerves?
what would happen if the anterior rootlets were cut? (1)
what would happen if the posterior rootlets were cut (2)
what would happen if the spinal nerve was cut (3)
what would happen if the posterior rami (ramus) was cut? (4)
What are the different spinal meninges?
what do we need to know about the dura mater?
surrounding the entire spinal cord from the cervical region to the tapering end of the dural sac
- tough mother known as a very tough superficial layer
- goes to the S2
-creates the sac that surrounds the spinal cord and the proximal aspects of the cauda equina and the spinal cord roots
-it also extends laterally and surrounds each pair of the spinal nerve roots in the dural root sheaths
what do we need to know about the arachnoid matter?
intermediate to the pia and the dura
- due the the presence of cervical spinal fluid deep into the layer of the arachnoid matter, actually directly adheres to the internal surface of the dura
- reflecting dura away from the spinal cord, you are also reflecting arachnoid matter
-have arachnoid trabeculae weblike connective tissue from arachnoid matter to the pia matter.
what do we need to know about the pia matter?
most delicate layer, and deep layer
also known as tender mother
- when we reflect the spinal cord and arachnoid matter away, we can see the pia matter directly on the spinal cord
- laterally from pia matter is a denticulate ligament, which anchors the pia mater to the arachnoid-lined dura
