TEST 1- CNS/PNS Flashcards
We have 33 vertebra. How are they separted? (# and segments)
7 cervical 12 thoracic 5 lumbar 5 fused sacral 3-5 coccygeal
4 main curvatures
Cervical curves anteriorly
Thoracic curves posteriorly
Lumbar anteriorly
Coccygeal/sacral posteriorly
This faces anteriorly, and is the weight bearing portion of the vertebra
Body
Extends posteriorly on both sides
Pedicle
Posterior to the pedicle is the _______ which joins with the pedicle to form the transverse process
Lamina
Forms the spinous process (faces posteriorly)
2 lamina formed together
Attachment site for many of the muscles of the back and the neck
Spinous process
Where vertebra articulate with one another (located on superior articular process)
Facet
What sits inside the vertebral foramen?
Spinal Cord
The ________ articular process articulates with the _________ articular process of the vertebra just below it.
Inferior articular process articulates with the superior articular process of the vertebra below it
What forms the intervertebral foramen?
Inferior intervertebral notch
Superior intervertebral notch
What passes through the intervertebral foramen?
Blood vessels and spinal nerves
C1 is also called ______
Atlas
Greek mythology–atlas holding world on shoulders
The vertebral foramen is WIDE/NARROW at C1
Wide
C1 has NO body and no spinous process associated with it. TRUE/FALSE.
TRUE
What articulates with the superior articular facets of C1
Occipital condyles
C2 is also knows as the _____
Axis
This is a structure on C2, fractured frequently with neck fx’s, also known as ondontoid process.
Dens
What is the purpose of the dens articulating with the atlas?
Allows head to rotate left and right; provides pivot for head to rotate.
The superior articular facet of C2 will articulate with what??
Inferior articular facet of C1 (atlas)
Most of the spinous processes of the cervical vertebra are ________,or have a split in them.
Bifid
Why are the spinous processes of the cervical vertebra bifid?
So muscles of the neck can attach to the spinous processes.
What articulates with the superior articular facet of C5?
Inferior articular facet of C4
What does the inferior articular facet of C5 articulate with?
Superior articular facets of C6
At C5, the spinous processes are more VERTICAL/HORIZONTAL.
HORIZONTAL.
Openings in transverse processes are characteristic of ___________ vertebra.
Cervical vertebra
In most ppl, the vertebral prominance (when bend head down) is _______ vertebra.
C7
Why is C7 important for us as anesthesia providers?
Good landmark for us to start with if need to work our way down to find vertebra intended for spinal anesthesia.
2 characteristics of cervical vertebra ?
Bifid spinal processes
Openings in transverse processes
Spinous processes are very SHORT and FAT in the thoracic vertebra. TRUE/FALSE.
FALSE
Long and thin spinous processes
The body of vertebra INCREASES/DECREASES in size as you go down the vertebra, because of weightbearing.
Increases in size as weightbearing increases
The vertebral foramen is smaller in the thoracic vertebra than it is in the cervical. TRUE/FALSE
TRUE
In the first 10 thoracic vertebra, there are articulations for the ______.
Ribs
When doing spinal in the thoracic region, you have to aim the needle more _________ bc of the way the spinous processes are angled.
Cephalad
What are the floating ribs?
Ribs 11 and 12
Thoracic vertebra are the ONLY vertebra that have articulations for the ribs. TRUE/FALSE
TRUE
The head of the rib articulates with the ________ articular facet of the superior vertebra and the _______ articular facet of the inferior vertebra
Inferior; superior
Tubercle of the rib sets against the articular facet on the __________ of the inferior vertebra.
Transverse process
Lumbar vertebra are the LARGEST nonfused vertebra. TRUE/FALSE
TRUE
What would the inferior articular facet of L5 articulate with?
Superior articular facet of S1
Spinous processes of the _______ vertebra are very wide, thick, and horizontal.
Lumbar vertebra
This is at S1, important for determining width of the birth canal.
Sacral promontory
Opening at S5. Clinical significance?
Sacra hiatus
Caudal block for pediatrics (for urologic procedures)
Which 2 sets of vertebra are fused together?
Sacral vertebra
Coccyx
On average, we have _______ coccyx vertebra.
3-5
There is a _________ area where the sacrum and coccyx meet.
Flexible
There are NO vertebral foramina or transverse processes associated with the coccyx. TRUE/FALSE
TRUE
Fibrocartilagenous discs between adjacent vertebral bodies
Intervertebral discs
Intervertebral discs allows for what in the vertebral column
Cushioning and flexibility
Where do vertebral discs start and end?
From (axis) C2 to the sacrum (between L5 and S1)
There are NO vertebral discs between which cervical vertebra.
No vertebral discs between the Atlas and the skull; and none between the Atlas and the Axis
Vertebral discs provides for ~ ___% of the length of the vertebral column
25 %
As we get older, the vertebral discs _______, and they are shortened
Dehydrate (shrink)
2 main parts that compose a vertebral disc
Nucleus pulposus (center) Annulus fibrosis (outer fibrous rings)
Condition when nucleus pulposus herniates through annulus fibrosus
Herniated disc
Discs usually herniate ANTERIORLY/POSTERIORLY
POSTERIORLY
What is compressed with posterior herniated disc?
Spinal nerve root in the intervertebral foramen
With posterior herniated disc, there is usually _______ deficit first with _______ root compressed.
Sensory deficit with dorsal root compressed
When ventral root is compressed in the spinal nerve from herniated discs, you will see _______ deficits
Motor
What part of the vertebral column must the surgeon remove to get to the herniated disc?
Lamina (laminectomy)
This ligament runs down the anterior part of the vertebral column from the atlas to the sacrum
Anterior longitudinal ligament
The anterior longitudinal ligament DECREASES in size as goes down the spinal column. TRUE/FALSE
FALSE
INCREASES in size and goes downward
Ligament that runs along posterior surface of vertebral bodies from axis to the sacrum
Posterior longitudinal ligament
What happens to the size of the posterior longitudinal ligament as runs down vertebral column?
Starts large at the top and gets smaller at the bottom
Connects the lamina to each other on both the L and R.
Ligamenta flava
Needle goes in this opening for spinal
Space between L/R ligamenta flava
Runs from C7 to sacrum; connects tips of spinous processes.
Supraspinal ligament
Above C7, what connects spinous processes?
Ligamentum nuchae
Connects the roots and apexes of spinous processes
Interspinal ligaments
Connects adjacent transverse processes
Intertransverse processes
Spinal cord is a continuation of the _______
Medulla or brainstem
In the avg adult the SC is ~ ____ cm long
46 cm
SC extends from the foramen magnum to the ____________ (endpoint of SC)
Conus medullaris
In most adults, SC ends at Lumbar vertebra ______
L1
What space do we typically put in a spinal/epidural?
L3/L4
Fibrous structure extending from conus medullaris to coccyx and anchors SC in place
Filum terminale
What are the two enlargements of the SC?
What’s the purpose of the enlargements?
Cervical enlargement
Lumbosacral enlargement
Large # of nerves that need to exit these areas to innervate the upper/lower body
Where do the nerves originate in the spinal column that innervate the upper limbs
C4-T2
Where do the nerves enter and exit to innervate the lower limbs?
L3-S3
Nerves from the lower part of the spinal cord that extend in a tail fashion.
Cauda equina
SC is bilaterally symmetrical. TRUE/FALSE
TRUE
Divides SC down the middle anteriorly
Anterior median fissure
Divides the SC posteriorly down the middle.
Posterior median sulcus
Part of the spinal cord that holds CSF; continuous with 4th ventricle.
Central canal of SC
Outer part of SC is composed of what?
White matter (bundles of axons and their myelin sheaths)
What type of information will be transmitted in ascending tracts of the white matter?
Sensory information up to the brain
What type of info is sent in descending tracts of the SC? (3)
Somatic motor
Autonomic pathways
Pain modulation
3 columns of the white matter?
Dorsal (posterior)
Ventral (anterior)
Lateral column
Central part of SC is composed of what?
Gray matter
Nerve cell bodies and their dendrites; where axons synapse with those dendrites
Gray matter
Gray matter is divided into _______.
Horns
What are the horns of the gray matter
Posterior horn
Anterior horn
Lateral horn
What segments have a lateral horn of gray matter?
T1-L2
S2-S4
Lateral horns of the gray matter are associated with ___________ output.
Autonomic
Anterior horns of the gray matter are associated with _______ output
Motor
Posterior horns associated with _________ INPUT/OUTPUT?
Sensory INPUT
Thin strip of white matter behind posterior horn of the gray matter.
Tract of lissaeur
__________ pathways must enter through tract of lissaeur before synapsing with posterior horn of the gray matter.
Sensory
Where pathways cross over from one side of the SC to the other side.
Anterior white commisure
Surrounds the central canal of the SC; pathways can also cross over from one side of the SC to the other here
Gray commisure
One of the few places in the gray matter where tracts are passing through
Gray commisure
Where anterior and posterior root join together
Common spinal nerve
What type of fibers are in the common spinal nerve?
Sensory
Motor
Autonomic
Sensory fibers out in the periphery come through the common spinal nerve, enters the _________ root, ______ rootlets, and synapses _______.
Dorsal root
Dorsal rootlets
Posterior horn of gray matter
Where do lower motor neurons/nerve cell bodies of lower motor neurons originate?
Anterior horn of the gray matter
Where do nerve cell bodies of upper motor neurons originate?
Primary motor cortex; frontal lobe
Upper motor neuron passes through brainstem and SC to synapse with ________ in the anterior horn of the gray matter
Lower motor neuron
After lower motor neuron is excited, what is its path from anterior horn to the skeletal muscle?
Sends impulses out through ventral rootlets; ventral root; common spinal nerve; synapse on skeletal muscle fibers; contraction.
Autonomic pathways start in the ________ horns, exit through the ______ rootlets, ________ root, common spinal nerve, and synapse on various tissues/organs with the autonomic innervation.
Start in the lateral horns, exits through ventral rootlets, ventral root..
Sensory fibers enter through the ______ root.
Dorsal root
Motor and autonomic fibers pass out through the _______ root.
Ventral
All the nerve cell bodies of the sensory pathways that are entering dorsal root and clustered where?
Dorsal root ganglion
The gray matter is divided into these divisions
Lamina of rexed
There are ___ different zones, bilaterally, of laminae of rexed.
10
These laminae of rexed are located on the dorsal horn of the gray matter and receive sensory input from peripheral afferent sensory neurons
Laminae of Rexed I - VI
Lamina of rexed _____ is where primary sensory neurons that transmit fast pain synapse.
Lamina of rexed 1
Lamina marginalis
Laminae of rexed II and III are collectively referred to as what?
Substantial gelatinosa
Primary sensory neurons that transmit slow pain synapse here
Laminae of Rexed II and III
Type of fibers and NT for fast pain?
Type A delta
Glutamate
Type of fibers/NT for slow pain?
Type C unmyelinated
Substance P
All sensations besides fast/slow pain terminate here (vibration, tickle, itch)
L of R IV, V, and VI
These Lamina of rexed are located in the anterior horn of the gray matter; contain nerve cell bodies of efferent somatic motor neurons.
LofR VII, VIII, IX
If lateral horns are present, which LofR are associated with them?
What type of output?
LofR VII
Autonomic output
Where is laminae of rexed 10 located?
Around central canal of SC (gray commisure)
The meninges of the of the SC are continuous with the ______
Brain
The dura mater of the SC has 2 layer. TRUE/FALSE.
FALSE.
SC only has ONE layer of dura mater.
How far does the dura mater extend down the spinal column?
S2
Longer than SC: ends blindly in pouch
The dura mater extends out to the dorsal roots, ventral roots and common spinal nerve, creating the covering of the common spinal nerve which is the ____________.
Epineurium
Dura mater is separated from the vertebral bodies which creates the __________ space.
Epidural space
Below the dura mater; potential space; thin film of fluid present.
Subdural space
Arachnoid mater extends past the SC, where does it end?
S2
Contains CSF, space around spinal cord that is continuous with the brain.
Subarachnoid space
Inseparable and attached directly to SC
Pia mater
Extension of the pia mater after the conus medullaris; anchors the SC down by piercing the arachnoid mater and dura mater and attaching to coccyx.
Filum terminale
Connects the pia mater to the dura mater; anchors SC down laterally. (22 of them)
Denticulate ligaments
31 spinal nerves. How many pairs and where?
8 pairs of cervical 12 pair of thoracic 5 lumbar 5 sacral 1 coccygeal
How are spinal nerves named?
Named form the spinal segment from which they originate
How are spinal cord segments named?
Vertebral column segments from which the originated in fetal development
As we get older, the vertebral column grows FASTER/SLOWER than the SC.
Column grows FASTER than SC
SC segments do NOT lay adjacent to vertebral column segments that they originated from during fetal development. TRUE/FALSE
TRUE
Upper SC segments sit adjacent with the corresponding vertebra from which they were named. TRUE/FALSE.
TRUE
Lower cervical regions, the vertebra are _______ lower in number than the corresponding SC segment.
One lower
Upper thoracic region, the vertebra are ____ lower in number than the corresponding SC segment
2 lower
Lower thoracic region, vertebra are _____ lower in number than corresponding SC segment
3 lower
Lumbar, sacral and coccygeal SC segments occupy the space opposite of what vertebra?
T9 - L1
Spinal nerves exit through the same vertebral foramen that they always exited from (creates cauda equina) TRUE/FALSE
TRUE
Spinal Cord segments and corresponding adjacent vertebra (adults) for spinal nerve C1-C8
SC - VERTEBRA
C1 - C1 C2 - C2 C3 - C 2-3 C4 - C 3-4 C5 - C 4-5 C6 - C5 C7 - C6 C8 - C6-7
SC segments and adjacent vertebra for T1 - T12 spinal nerves
SC - VERTEBRA
T1 - C7-T1 T2 - T1-2 T3 - T2 T4 - T3 T5 - T3-4 T6 - T5 T7 - T6 T8 - T7 T9 - T8 T10 - T9 T11 - T10 T12 - T10-11
SC segments and adjacent vertebra for L1-S5; Coc-1
SC - VERTEBRA
L1 - T11-12 L2 - T11-12 L3 - T12 L4 - T12-L1 L5 - T12-L1
S1 - L1 S2 - L1 S3 - L1 S4 - L1-2 S5 - L1-2 Coc1 - L1-2
Areas of the skin supplied by the various spinal nerves
Dermatomes
Dermatome level appropriate for spinal with an abdominal procedure
T4; nipple line
Dermatome level for gynecological/urologic procedures
T10; around umbilicus
Innervates the skin, muscles, and other structures of the back of the neck and the trunk. (Branch off of common spinal nerve)
Dorsal Ramus (rami)
Innervate the anterior and lateral neck, trunk, perineum, and the limbs. (Branch of spinal nerve)
Ventral ramus
This ramus does NOT form plexuses
Dorsal rami
This ramus forms various nerve plexuses
Ventral rami
From what spinal nerves does the cervical plexus receive contributions from?
C1, C2, C3, C4
Spinal nerves contributing to brachial plexus
C5, C6, C7, C8, T1
Most ppl C4, T2 as well
Spinal nerves contributing to lumbar plexus
L1, L2, L3, most of L4
Spinal nerves contributing to sacral plexus
Remainder of L4,
L5, S1, S2, S3
Spinal nerves contributing to sacrococcygeal plexus
S4, S5, and coccygeal nerve
How is the brachial plexus divided up?
5 Roots 3 Trunks 6 Divisions (3V/3D) 3 Cords 5 terminal Branches
What are the 5 (or 7) roots of the brachial plexus?
C5, C6, C7, C8, T1
C4, T2
Phrenic nerve is a branch off of the ____ root; innervated the diaphragm.
C5
What are the 3 trunks?
Superior
Middle
Inferior
The roots of the brachial plexus divide into ___ divisions, ______ dorsal and _____ ventral.
6 divisions
3 ventral
3 dorsal
How do the 6 divisions form into the 3 cords?
3 dorsal divisions form the posterior cord
2 ventral divisions form the lateral cord
1 ventral division forms the medial cord
6 Cords of the brachial plexus give way to what 5 terminal branches
Musculoskeletal Axillary Radial Median Ulnar
Musculocutaneous branch gets contributions from what roots?
C(4), C5, C6, C7
Axillary branch gets contributions from what roots?
C5, C6
Radial branch gets contributions from what roots?
C5, C6, C7, C8, T1
Median branch gets contributions from what roots?
C(5), C6, C7, C8, T1
Ulnar branch gets contributions from what roots?
C(7), C8, T1
Cutaneous sensory innervation of axillary nerve
Interior lateral shoulder
Cutaneous sensory innervation of radial nerve
Posterior surface of the arm and forearm, lateral 2/3 of the dorsum of the hand
Cutaneous sensory innervation of musculocutaneous nerve
Lateral surface of the forearm
Cutaneous sensory innervation of ulnar nerve
Medial third of the hand, little finger, and medial half of ring finger
Cutaneous sensory innervation of median nerve
Lateral 2/3 of Palm of hand, thumb, index and middle fingers, and the lateral half of ring finger and dorsal tips of the same fingers.
What nerve is most commonly damaged under general anesthesia? Why?
Ulnar nerve bc of compression from positioning arms wrong
Hands should be PRONATED/SUPINATED to prevent ulnar nerve injury.
SUPINATED
How many spinal arteries are there anteriorly?
One
How many posterior spinal arteries?
Two
The anterior spinal artery perfuses the anterior _______ of the SC
Ant 2/3 of the SC
The two posterior spinal arteries perfuses the posterior _______ of the spinal cord on each side.
Posterior 1/3 on each side.
Right posterior artery supplies posterior 1/3 Rt SC, visversa.
Arteries that are outside the vertebral column; run through intervertebral foramen; most only supply the nerve roots, but some perfuse parts of the meninges and ant/post SC.
Radicular arteries
Artery that runs the entire length of the SC, in front of the anterior median fissure.
Anterior spinal artery
What forms the most superior part of the anterior spinal artery?
Branches from the vertebral arteries
In most ppl, there are ~ ______ radicular arteries that supply blood to the anterior spinal artery
6-10
From cervical region, down to ~ T2, SC is perfused by radicular arteries from the __________ arteries.
Subclavian arteries
This segment of the SC has only one radicular artery, making it an area at risk for hypoperfusion.
T3 - T7
Supplies blood to anterior spinal artery from spinal segment T8, all the way down to the conus medullaris.
Artery of adamkiewicz
Artery of adamkiewicz is also called major anterior radicular artery, and in most ppl, rises from the Left ________ artery.
L posterior intercostal artery
The descending branches from the artery of adamkiewicz form an anastamosis around the conus medullaris and helps provide blood flow to what arteries.
Posterior spinal Arteries
Perfuses more SC segments than any other radicular artery
Artery of adamkeiwicz
Supplied blood by the lumbar, lateral sacral, and medial sacral arteries.
Cauda equina
Posterior spinal arteries do NOT run entire length of SC. TRUE/FALSE
FALSE
Posterior spinal arteries DO run the entire length of the SC.
Like anterior spinal artery, the posterior spinal arteries recieve blood from the _______ arteries.
Vertebral arteries
In most ppl ______ radicular arteries contribute to posterior spinal arteries.
10-23
Branch off of the anterior spinal artery and run along ant median fissure; supply many of the inner SC.
Central branches
Arteries that run along the surface of the SC and supply outer SC
Pial (arterial) plexus
Both the central branches and pial plexus have __________ branches that supply the inner SC
Penetrating branches.
3 concentric rings of the SC and what arteries supply them?
Inner ring: zone sup;inked by the central branches
Middle ring: zone supplied by both the central branches and branches from pial plexus
Outer ring: supplied by pial plexus branches only
The posterior spinal arteries have branches that give rise to the posterior pial plexus, but DO NOT have __________ branches
Central branches
Midline structures from posterior skin to epidural space.
Skin- post. Body Subcutaneous tissue Supraspinal ligament Interspinal ligament Gap: L and R ligamenta flava Epidural space
Midline structures from epidural space to central canal of SC.
Epidural space Dura mater Subdural space Arachnoid mater Subarachnoid space/CSF Posterior median sulcus Pia mater Posterior column white matter Posterior gray commisure Central canal of SC
Midline structures posterior from central canal of SC to epidural space on anterior side.
Central canal Anterior gray commisure Anterior white commisure Pia mater Subarachnoid space Arachnoid mater Subdural space Dura mater Epidural space
Midline structures (from posterior) from anterior epidural space to anterior longitudinal ligament.
Epidural space Posterior longitudinal ligament Anulus fibrosus Nucleus pulposus Anulus fibrosus Anterior longitudinal ligament
Dorsal column of the SC contains fasciculus ______ and fasciculus _______
Gracilis
Cuneatus
What spinal artery would supply the R fasciculus gracilus and R fasciculus cuneatus?
R posterior spinal artery
Which artery perfuses most of the posterior and anterior spinocerebellar tracts?
Anterior spinal artery
What artery supplies the anterolateral system
Anterior spinal artery
Composed of more than 1 pathways
System
Begins in the periphery, enters SC, runs up SC to brain; this sequence is called a __________
Pathway
Part of the pathway that is in the white matter of the SC or the white matter of the brain
Tract
Ascending sensory spinal pathways have _____ neurons in sequence up to the brain from the periphery. They are?
3
Primary
Secondary
Tertiary
Pain (fast and slow), temperature, light touch, pressure, tickle and itch are all info transmitted through ________ pathways
Spinothalamic pathway
Spinothalamic pathways begin in the ________ with free nerve endings
Periphery
With what two sensations, does the primary neuron of the spinothalamic tract cross over at the exact spinal segment it enters at?
Pain
Temperature
Primary neuron synapses with secondary neuron where?
Posterior horn of the gray matter
Pathway of secondary tract up to synapsing with tertiary neuron:
Crosses over and enters spinothalamic tract; ascends up SC, medullar, pons, midbrain, and terminates in one of the nuclei of the thalamus
Where does the secondary neuron synapse with the tertiary neuron in a sensory spinothalamic pathways
Thalamus
Tertiary neuron travels up to the primary sensory cortex according to the __________
Sensory humunculus
Why are all other sensations difficult for the brain to localize, other than pain and temp?
When primary neuron enters, gives off collaterals that can ascend/descend a few spinal segments before entering the dorsal column of the gray matter
If interrupted tx in the primary neuron, what side would be affected? What area would be affected?
Same side/ipsilateral
Just the areas of the skin innervated by that primary neuron
If spinothalamic tract was interrrupted, which side affected? How much area affected?
Contralateral
Effects everything below the level of the lesion
What composes the dorsal column/medial lemniscal system? (2)
Fasciculus cuneatus
Fasciculus gracilis
Type of information transmitted through dorsal column/medial lemniscal system?
Proprioception (conscious)
2 point discrimination
Pressure
Vibration
2 point discrimination; how close until feels like only one point: hand _____ mm; back: ______ mm
Hand 2-5 mm
Back ~ 20 mm
More sensory receptors on fingers
Dorsal column/medial lemniscal system begins with modified nerve ending called ________
Pacinian corpuscle
When primary neuron enters dorsal column of gray matter, it directly enters fasciculus cuneatus OR gracilis. TRUE/FALSE.
TRUE
Sensations from the midthorax, up to the neck are tx through fasciculus ___________
Cuneatus
Sensations from midthorax to the toes is tx through fasciculus ________
Gracilis
Primary neuron synapses with secondary neuron in the nucleus gracilis or cuneatus in the ___________ of the brain.
Medulla
The secondary neuron in the dorsal column/medial lemniscal system, crosses over at the ________ and enters the ___________ (runs up through pons/midbrain)
Crosses over at the medulla
Enters the medial lemniscus
2ndary neuron travels up medial lemniscus and terminates and synapses with the tertiary neuron where?
In a nucleus of the thalamus
What is the pathway of the tertiary neuron after medial lemniscus and thalamus?
Ascends up to primary sensory cortex, postcentral gyrus, according to the layout of the humonculus
Spinocerebellar pathways transmit primarily what type of info?
Unconscious proprioceptive
Spinocerebellar pathways start in the periphery with what two things?
Golgi tendon bodies
Primary muscle spindles
Primary neuron of the spinocerebellar tract enters into dorsal horn of gray matter, synapses with nerve cell body of secondary neuron which enters into the posterior spinocerebellar tract on the SAME SIDE of the SC. TRUE/FALSE?
TRUE
The secondary neuron travels up posterior spinocerebellar tract, inbetween the medulla and pons, it goes back and synapses in the cerebellum on the SAME SIDE. TRUE/FASLE?
TRUE
The posterior spinocerebellar tract crosses over. TRUE/FALSE.
FALSE
Posterior DOES NOT cross over
Posterior spinocerebellar pathways do not cross over and have only 2 neurons in sequence; but the tertiary neuron is actually located where?
In the cerebellum
What is different about the anterior spinocerebellar tract?
It crosses over twice; ends up on the same side it entered
What two places does the neuron cross over in anterior spinocerebellar pathways.
Crosses over after synapsing with 2ndary in posterior gray horn into ant whit commisure of the opposite side
Crosses over again between medulla and pons
Descending motor pathways start where?
In the brain
Corticospinal pathways are part of the _________ pathways bc they pass through the pyramids on the ant/inf surface of the medulla.
Pyramidal pathways
Pathways that provide muscle movement from the neck, all the way down to the toes
Corticospinal pathways
Corticospinal pathways have to do with CONSCIOUS/UNCONSCIOUS muscle movement
CONSCIOUS
Corticospinal pathways start where?
Frontal lobe, precentral gyrus, primary motor cortex
Descending motor pathways are composed of _______ neurons in sequence
2
Upper motor neuron
Lower motor neuron
Lateral corticospinal pathways cross over the SC to the other side and enter the lateral corticospinal tracts on the opposite side at the medullar, at the pyramids; this composes ~ ____% of descending motor pathways.
80%
The remaining 20% of (anterior) corticospinal tracts, upper motor neurons travel down SC and cross over where?
At the spinal segment where the lower motor neuron will exit
Which ar the more important motor pathways of the corticospinal pathways?
Lateral corticospinal tracts
Interrupted tx in the anterior corticospinal tract will have __________ side effects.
Contralateral
Interruption of lateral corticospinal tract will affect __________ side
Ipsilateral
These pathways are for control of conscious skeletal muscle movements of the head and face
Corticobulbar pathways
Upper motor neurons of corticobulbar pathways originate in the ___________ according to the layout of the homunculus
Cerebral motor cortex
Lower motor neurons of corticobulbar pathways are _____________ with a motor component
Cranial nerves
Which cranial nerves have a motor component; acting as lower motor neurons in corticobulbar pathways?
III (oculomotor) IV (trochlear) V (trigeminal) VI (abducens) VII (facial) IX (glossopharyngeal) X (vagus) XI (spinal accessory) XII (hypoglossal)
The upper motor neurons of most (not all) corticobulbar motor pathways originate in both left and right primary motor cortices of the cerebral hemispheres. TRUE/FALSE
TRUE
Corticobulbar pathways contain only crossed fibers. TRUE/FALSE
FALSE
Pathways contain crossed and uncrossed fibers
These pathways do not cross through the pyramids of the medulla and are responsible for unconscious skeletal muscle movement
Extrapyramidal pathways
Extrapyramidal pathways integrate with what 2 things to bring about smooth muscle movement
Basal nuclei
Cerebellar hemispheres
What type of drugs caused lots of extrapyramidal manifestations?
Old antipsychotic drugs
Extrapyramidal side effects include what?
Unsteady gait Ataxia Writhing arm movements Lip smacking Tongue rolling
What drug can we give to control extrapyramidal manifestations?
Benadryl
Hemisection, or incomplete, SC lesion.
Brown-sequard syndrome
With Brown-Sequard syndrome, there is CONTRALATERAL/IPSILATERAL upper motor neuron damage and loss of proprioception.
Ipsilateral
With Brown-Sequard syndrome, there is CONTRALATERAL/IPSILATERAL loss of pain and temperature sensation.
CONTRALATERAL
