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94 Cards in this Set

  • Front
  • Back
The spinal cord is a continuation of what?
Where does the spinal cord begin and end?
exits from the foramen magnum and ends at L1-2
Do spinal cord segments correspond to vertebral segments?
How many pairs of spinal nerves are there?
Discuss the exit of nerves from the vertebra.
there are 8 cervical nerves, the first one exits above the atlas, therefore C8 is below C7, for the rest of the spinal cord the nerve exits below the corresponding vertebra
What occurs as one moves cranial to caudal w/ regards to spinal nerves?
nerves run progressively longer distances within the spinal canal before exiting
What does the cervical enlargement accommodate?
spinal segments C4 to T1 for brachial plexus
Where is the lumbosacral enlargement?
from L1 to S3 spinal segments, but T11 to L2 vertebral segments
What are the 3 parts of the meninges of the spinal cord?
dura, arachnoid and pia mater
What is between the dura mater and periosteum?
extradural or epidural space
Where does the dura mater end?
What is inside of the dura mater?
arachnoid mater and denticulate ligament
What is the ribbon-like structure that extends laterally from the midline on each side of the spinal cord? What is its purpose?
denticulate ligament
stabilizes the spinal cord within the dura
Is the dura free within the vertebral canal?
What is the dura mater continuous with at the foramen magnum?
cranial dura
What is located outside of the spinal dura mater? (what makes up the epidural space)
fat, arteries, veins, then periosteum
What is the characteristic of the arachnoid mater on the dural surface?
It is impermeable to most fluid flow and is thus responsdible for containing the cerebral spinal fluid
What does the pia mater enclose?
the network of blood vessels supplying the spinal cord
What is the combination of the pia mater and the inner portion of arachnoid mater that surrounds the brain and spinal cord?
Where does the spinal cord end (give its formal name)? Where does the dura mater and subarachnoid space end? What is the name of the area between these 2 areas?
L1-2, conus medullaris
from L2 to S2 is the lumbar cisterna
What are the 2 parts of the lumbar cisterna?
cauda equina
filum terminale
What is the name of the spinal nerves that are distal to the conus medullaris?
cauda equina
What is the strand of CT that extends from the end of the conus medullaris (L2) and attaches inferiorly to the dural sac (S2)?
filum terminale
What attaches to the periosteium of the coccyx and is located below the dural sac? When it flexes what is the result?
filum terminale externa (central ligament)
pulls the spinal cord anteriorly
What is the space between the periosteum of the vertebra and the dura mater of the spinal cord?
epidural space
What is the epidural space surrounded by? (anteriorly, laterally, posteriorly)
anteriorly-posterior longitudinal ligament, intervertebral discs and bodies of vertebrae
laterally-periosteum on the pedicles and 48 intervertebral foramen
posteriorly-laminae and ligamentum flavum
What occupies the epidural space?
fat, loose CT, internal vertebral venous plexus
What is the potential space between the dura and the fluid-impermeable portion of the arachnoid layer?
subdural space
What is the space between the arachnoid layer lining the dura and the arachnoid layer external to the pia? What is it filled with?
subarachnoid space
filled w/ CSF and arachnoid trabeculae
where is the largest spinal subarachnoid space?
caudal to the conus medullaris (L1-2) and cranial to S2
What does the CSF serve as?
mechanical and protective support for the brain, ion sink, so important for brain excitability
Discuss the volume of CSF and its distribution.
120-150mL total
95ml within and surrounding brain
35-55ml surrounds spinal cord
about 450-500ml produced daily
What is the normal specific gravity and color of CSF?What is its normal pressure?
70-180 mm Hg
Where is the majority of CSF produced?
choroid plexuses within the lateral third and fourth ventricles
Describe the path of CSF.
CSF produced in lateral ventricles and passes to the interventricular foramina into the third ventricle, down the cerebral aqueduct into the fourth ventricle and out either the median aperture or two lateral apertures
What are subarachnoid cisterns?
places where the subarachnoid space is larger
What is the cerebellomedullary cistern?
the largest subarachnoid space
How is CSF absorbed back into the venous blood?
through arachnoid villi along the superior sagittal sinus
Where is a spinal tap typically done?
between L3/L4 or L4/L5
List the structures in order that a spinal tap needle must penetrate. (8)
-subcutaneous tissue
-supraspinous ligament (toughest)
-interspinous ligament
-ligamentum flavum (tough)
-fatty tissue and venous blood within dural space
-dura mater (tough)
-arachnoid mater and into subarachnoid space
Which nerve, that is resoponsible for innervating the spinal canal, arises from the dorsal ramus? ventral ramus?
articular nerves
recurrent meningeal nerves
what do articular nerves innervate?
facet joint, ligamentum flavum, interspinous ligament, supraspinous ligament
Why may it be necessary to block more than a single vertebral level?
articular nerves often innervate two vertebral levels
What do recurrent meningeal nerves innervate?
anterior longitudinal ligament, dorsal longitudinal ligament, vertebral periosteum and dura mater of spinal cord
Extrinsic arteries give off arteries that supply blood to the spinal cord. Name them. (6)
vertebral artery (branches off subclavian)
ascending cervical branches off inferior thyroid artery
deep cervical artery
posterior intercostal
lateral sacral
Which arteries supply blood to the vertebrae?
Which arteries supply blood to the anterior and posterior spinal arteries?
What is the relationship in size of ventral vs dorsal medullary arteries?
ventral are larger in diameter
All ventral medullary arteries join what?
the anterior spinal artery
What supplies the spinal cord blood between T8 and L3? What does it arise from?
great ventral medullary artery (or major anterior radicular artery) of Adamkiewicz
it arises from the inferior intercostals or superior lumbar arteries
When repairing abdominal aneurysms what has helped to protect the spinal cord from ischemia?
epidural cooling
Three longitudinal arteries run just external to the pia mater in the subarachnoid space. What are they?
one anterior spinal artery
two posterior spinal arteries
Where does the anterior spinal artery run and what does it supply?
runs in the midline and supplies the anterior 2/3 of spinal cord, including most gray matter
Where does the anterior spinal artery branch from?
verterbral arteries
Where do the posterior spinal arteries run and what do they supply?
run posterior to the dorsal roots
supply posterior 1/3 of spinal cord
Where do the posterior spinal arteries branch from
posterior cerebellar arteries
How many central arteries are there and where do they branch from?
200-300, branch off the anterior longitudinal spinal artery
What do central arteries supply?
gray mater and anterior 2/3 of spinal cord
What do perforating branches off the pia and posterior arterial plexus supply?
mainly white matter in posterior 1/3 of spinal cord
Name the intrinsic arteries.
centarl arteries
perforating branches
During repair of lower thoracic and upper lumbar aortic aneurysms the aorta is often clamped above and below the aneurysm. Epidural cooling is used to cool the spinal cord w/ cold saline. What does this do? Why is this important?
reduces the metabolic needs of the spinal cord
the great anterior medullary artery of Adamkiewicz loses normal blood flow
helps prevent paralysis
What are the intrinsic veins of the spinal cord?
central (sulcal) veins
radial veins
What do central veins drain?
medial ventral gray mater
What do radial veins drain?
all of the spinal cord minus medial ventral gray mater
The anterior spinal veins and three posterior spinal veins located in the extradural space form what?
internal vertebral venous plexus
The internal vertebral venous plexus receives blood from what?
radiculomedullary veins
The internal vertebral plexus is valveless and drains where?
superiorly into the occipital sinus
also drains into intervertebral veins, ascending lumbar veins, and azygos venous sytem
Where does blood leave the epidural space?
at intervertebral veins
What does the spinal cord connect?
Collections of nerve cell bodies in the spinal cord form what?
H-shaped gray matter
Which part of the nervous system is responsible for movement and body functions?
Which horns are sensory? motor?
Where does the somatic motor nerve cell body lie? sensory?
ventral horn
dorsal root ganglia
What is the sectioning of the dorsal or ventral roots of a spinal nerve in order to relieve intractable pain or spastic paralysis?
What is the ANS classically defined as?
a visceral motor system that modulates internal organ function
What are the 2 divisions of the ANS? What part of the spinal cord do they make up?
What 2 motor neurons do the SNS and PNS viseral motor systems use?
preganglionic nerve
a second postganglionic nerve
Where is the preganglionic nerve cell body located?
in the CNS
Where is the postganglionic nerve cell body located?
in a ganglia in the periphery
What is a ganglia?
aggregation of nerve cell bodies located in the peripheral nervous system
What is the function of the SNS? PNS?
fight or flight
feed and assimilate
Why is it that if you destroy sympathetic nerves you destroy afferent nerves to that organ as well?
generally afferent nerves from viscera pass back to the CNS w/ sympathetic nerves
In the pelvis, viscera afferents generally pass back to the CNS w/ what type of nerves?
Where are preganglionic nerve cell bodies of the SNS located? (what levels)
in the intermediolateral column of the spinal cord from T1-L2
What are some examples of preganglionic sympathetic nerves that skip the synapsing in the paravertebral chain ganglia and synapse instead on postgaglionic nerves in prevertebral ganglia?
celiac, superior and inferior mesenteric prevertebral ganglia
What is the preganglionic neurotransmitter for the SNS?
What is the postganglionic neurotransmitter for the SNS?
Why does generalized sympathetic response occur?
preganglionic fibers may synapse on up to 30 postganglionic fibers
Which cranial nerves does the PNS contain? sacral?
cranial nerves III, VII, IX, and X
sacral at levels S2,3,4
In the preganglionic parasympathetic nerves long or short? postganglionic PNS?
Is there a generalized PNS response?
no, the pre to post ganglionic fibers is generally 1:1
What NT is used for PNS at both terminals?
What is pain over a given region of skin that is actually caused by disease from an internal organ?
referred pian
What is the theory that pain fibers from both internal organs and the body wall synapse on the same nerve (second order afferent) within the spinal cord?
afferent nerve convergence
the brain has no mechanism of knowing whether the pain is from visceral or somatic rgion, most pains are from somatic regions, so the brain often perceives the pain as somatic pain