Spinal Cord and Meninges Flashcards
How many cranial nerves in PNS?
12 pairs
how many spinal nerves in PNS?
31 pairs
what composes the PNS?
cranial and spinal nerves
what comprises the CNS?
spinal cord and brain
what is somatic?
receiving and responding to information related to external environment
what is visceral autonomic function?
innervation of internal organs, smooth muscle, and glands, detects and responds to internal stimuli
what is in gray matter?
cell bodies
what is in white matter?
myelinated axons
what information does the posterior root get, where does it enter?
sensory, afferent, dorsal horn
what information does the anterior root give, where does it exit?
motor, efferent, exits at the ventral horn
what is contained in the spinal ganglion (or dorsal root ganglion)?
neuron cell bodies
what is a ganglion?
collection of cell bodies in the PNS
what is a collection of cell bodies in the CNS
nucleus
what is the spinal nerve ACTUALLY, and where is it located?
a mixed motor and sensory nerve, posterior and anterior roots combined, located in the intervertebral foramen
once the spinal nerve splits after exiting the intervertebral foramen, what does it become?
the anterior ramus and the posterior ramus
what does the posterior ramus innervate?
deep back muscles, skin of back, joints between vertebrae
what does the anterior ramus innervate?
anterolateral body wall muscles (trunk) and skin, limb muscles and skin (everything else)
what does the anterior ramus branch out to become?
forms plexus - cervical, brachial, lumbar, sacral
what nerves does the cervical plexus include?
C1-C4
what nerves does the brachial plexus include?
C5-T1
what nervse does the lumbar plexus include?
L1-:4
what nervse does the sacral plexus include?
L4,5 and S1-S4
what is a myotome?
muscle fibers that are suppluied by a single spinal nerve
what is a dermatome?
an area of skin that has sensory innervation from a spinal nerve
list the order of meninges from deep to superficial?
pia mater, arachnoid mater, dura mater
what structures are superficial to the dura mater?
the epidural space which contains the posterior and anterior internal vertebral venous plexus and epidural fat, and nerves
what is in the subdural “space”
it is actually a potential space, no actual space, because the CSF presses the arachnoid mater into the dura mater
what is in the subarachnoid space?
CSF, spinal arteries and veins - is between arachnoid mater and pia mater
where does the spinal cord begin and “end” in an adult?
at the foramen magnum, to L1-L2
where does the spinal cord end in a newborn?
L3-L5
what is the end of the spinal cord called?
conus medullaris
what are the numbers of the spinal cord segments? NOTE spinal cord segments do not match vertebral body segments
cervical -8 thoracic - 12 lumbar - 5 sacral - 5 coccygeal - 1
where do the 1st 7 cervical spinal nerves exit?
above the vertebra for which they are named
where does C8 exit?
below C7 and above T1
where do the thoracic (to Co) nerves exit?
below the vertebra for which they are named
what is the cauda equina?
the spinal nerve roots in the lumbar cistern past the termination of the spinal cord in the conus medullaris
what are the lateral extensions of the pia mater that help anchor the cord within the dural sac?
denticulate ligaments
what is the function of the denticulate ligaments?
they are extensions of the pia mater that anchor the cord to the dural sac
what is the filum terminale?
the terminal extension of the pia mater, it pierces the dura to anchor the inferior end of the spinal cord
what shiny connection in the cauda equina acts to anchor the inferior end of the spinal cord?
filum terminale
where is the lumbar cistern located?
L2-S2
what is the function of the lumbar cistern?
it contains CSF, nerve roots of the cauda equina, and is a continuation of the subarachnoid space within the dural sac
where would one perform a lumbar puncture?
in the lumbar cistern between L2 and S2, in the subarachnoid space, DISTAL to conus medullaris
TO KEEP THE CORD ALIVE, KEEP THE SPINAL NEEDLE BETWEEN L3 AND L5
where does the dural sac end?
S2
what meninges are pierced during a lumbar puncture?
the dura and arachnoid mater
what meninges are pierced during an epidural?
NONE, the catheter is placed in the epidural space
where do the rami exit past the sacral canal?
through the sacral foramina
the dural sac (along with the dorsal and ventral roots) continues into ___ and ends at ____
the sacral canal, S2 segment
which arteries supply the spinal cord?
1 anterior spinal longitudinal artery, and 2 posterior spinal longitudinal arteries
where do the longitudinal arteries originate from?
the vertebral artery
where does the anterior spinal artery run?
in the anterior median fissure of the spinal cord, and supplies anterior 2/3 of the spinal cord
where does the posterior spinal artery run?
the 2 posterior spinal arteries fun next to each dorsal root entry zone and supply posterior 1/3 of spinal cord
what branches off of the anteior and posterior spinal arteries?
vertebral, intercostal, lumbar and sacral segmental medullary arteries
what is the major blood supply for the lumbar and sacral cord?
the great anterior segmental medullary artery of adamkiewicz
what are the major veins for the spinal cord?
the internal venous plexus and longitudinal veins (anterior spinal vein)
where is the internal venous plexus located?
in the epidural space, superficial to the dura mater
when do the dural sac and subarachnoid space end?
S2
when does the spinal cord end in adults?
inferior border of L1 or superior border of L2
where is it safe to insert a needle for a spinal tap?
above or below L4
where is there NOT inververtebral discs?
C1/C2 and after S1 (there is one between L5/S1)
what types of joints are between vertebra/inververtebral discs?
cartilaginous joint
where is the conus medullaris?
L2
