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Spinal cord1.
Medullaa.
Ponsb.
Midbrainc.
Brain stem2.
Cerebellum3.
Diencephalon (Thalamus & Hypothalamus)4.Cerebrum (Cortex)5.
Neuraxis/Neural axis (from bottom to top)
Neural AxisMay-12-10
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Responsible for simple reflex motor actions(ie: removing hand from hot plate)
Spinal cord is 45 cm long inside vertebral column (60-75 cm)
Cont'n of brain stem (medulla oblongata) at the level ofC1 (atlas) thru the for magnum
Adults: L1/L2 intervertebral disc (ie: occupies upper 2/3 of vertebral column due to
the differential growth of the column)
o
Infants: L3o
In utero = entire length of the vertebral columno
Spinal cord ends at
Conus medullaris: the lower edge of the spinal cord (from L1/L2 for adults and L3 in infants)
Rootletsattach to the spinal cordo
Posterior (Dorsal) root --> Dorsal root (Spinal) gangliono
Anterior (Ventral) rooto
Mixed Nerveo
Posterior (Dorsal) ramuso
Anterior (Ventral) ramuso
Neuromere = region of the spinal cord that gives off a pair of spinal nerves (31 segments)
Spinal segment: C8, T12, L5, S5, Cx1 (total = 31)
Vertebrae: C7, T12, L5, S5, Cx3 (the coccygeal vertebrae are fused hence total = 30; unfused
total = 33)
Segmental (regional) anesthesia in epidural space at specific dermatome
Laminectomy:removal of lamina of vertebra to release pressure on spinal cord from tumors
C7 end of the necko
L4 - at the level of the iliac cresto
Bony vertebral prominences:
Cervical spine + 1 (ie: 5th spinal segment is opposite to 4thcervical spine)o
Upper thoracic (T6) + 2 (ie: 5th upper thoracic segment is across 3rd T3 spine)o
Lower thoracic (T7-T10) + 3o
T11 + 4 (L3 spinal segment)o
T12 + 6 (S1 spinal segment)o
After L1 add requisite spinal spineso
Rules for determining location of the spinal segment (go down!!):
Cervical enlargement (C5-T1) --> to accommodate the brachial plexuso
Lumbar enlargement (L1-L4) --> to accommodate the lumbo-sacral plexuso
2 enlargements of the spinal cord (to accommodate increased number of neurons)
Anterior median fissure (AMF)o
Anterolateral sulcus (ALS)o
Posterior median sulcus (PMS)o
Posteriorlateral sulcus (PLS)o
Longitudinal fissures:
The spinal cord has been divided into two equal halves by the AMF and the two halves are
connected by the white commissure and grey commissure (nerve fibres)
The periosteum of the cranium is replaced by the pericranium (5 th layer of scalp)o
Outer endosteal layer
Inner meningeal layer --> forms tentorium cerebri, tentorium cerebelli, etc.
Cerebral Dura Mater: 2 layers separated by dural venous sinuseso
NO epidural space bc outer endosteal is part of pericranium (potential space)o
Epidural hematoma needs to be resolved within 24 hrs otherwise death will resulto
Cerebral Dura Mater covers the brain
Spinal Dura Mater (only one layer) & considerable epidural space
Arachnoid mater
Spinal Pia mater
Meninges of the spinal cord
Spinal Cord (Spina Medullaris)May-13-10
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Extends from the margin of the foramen magnum to the S2 vertebra
Fato
Radicals of veins
Caval system of veins
Azygous system of veins (not paired with arteriesslow )
Thyroid gland veins
Prostrate veins
Breast veins
Lymphatics
Venous systemArterial system
Organ to organ
4 possible routes of metastasis (in order):
Due to the vertebral venous plexus, there can be metastasis from different
organs to the spinal cord, hence causing compression of the spinal cord
Vertebral venous plexus of Baton (Valveless --> hence blood can flow in both
directions): Normal changes in the abdominal or intrathoracic pressure (-3 to -4
mmHg) does not alter flow in these veins howevercoughing, sneezingdoes
Communicates with the:
o
Roots of the spinal nerve (hence segmental/regional/epidural anesthesia can be
achieved via the epidural space)
o
Epidural space
Most common procedure: Childbirtho
Through the sacral hiatuso
Epidural anesthesia
Subdural space: between dura mater & arachnoid mater
Spinal Dura Mater
Extends from the margin of the foramen magnum to the S2 vertebra
Subarachnoidspace: bt arachnoid mater and spinal pia mater
Cerebral Cysterms:enlarged subarachnoid space at base of brain; contains CSF
Function: Protection ofcauda equinao
Spinal Cysterns:enlarged subarachnoid space w/ CSF from L1-S2 of spinal cord
Arachnoid Mater (avascular)
The pia mater ends at the dorsum of the coccyx
extensions from pia mater that att to inner surf of dura mater = anchorage
This ligament = partition bt dorsal & ventral roots (helps identification)
Selective Risotomy: cutting some of the rootlets in the sensory dorsal root
Ligamentum Denticulatum (21 pairs):o
Linea Splendence: Thickened part of the pia mater in the region of the anterior
median fissure (no clinical significance)
o
Thread-like extension of pia mater from tip of the conus medullaris
S2 --> pierces arachnoid & dura mater and attaches to dorsum of coccyx
Anchoring capacity to the spinal cord during extreme flexion
Filum terminale internum (Up to S2)
Filum terminale externum (after piercing the 2 meninges past the level of S2)
Filum Terminale (not very vascular)o
Modifications of the spinal pia mater
Tip of spinal cord has appearance of a horse tail since the spinal cord ends at L1/L2o
Lower 4 Lumbar nerves, Sacral, Coccgeal nerves and the filum terminale (non-
o
Cauda Equina
Spinal Pia Mater (Vascular layer)
Spinal Cord Cont'dMay-14-10
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nervous part of the cauda equina)
Performed at the level ofL3-L4 preferably (or between L2-L3)
Purpose:Spinal anesthesia, sampling of the CSF (microbiological, pathological analysis)
Position:Extreme flexion/Lateral decubitus (so that the spinal cord moves up)
Skino
Connective tissue (superficial/deep fascia)o
Supraspinous ligamento
Interspinous ligamento
Ligamentum flavumo
Dura Matero
Arachnoid matero
Layers pierced before reaching the subarachnoid space (from outside to inside):
When blood seen in needle = reached epidural space (due to venous plexus), go further in
Rate of collection of CSF:1 drop/min
Increased ICP (Normal ~ 0-20 mmHg in supine and -10mmHg in the vertical position)
= herniation of cerebellar tonsils and medulla (resp & CVS center) thru for magnum
o
Contraindications for LP
Normal CSF P: Supine = 80-100 mmH2O; Standing = 300-400 mmH2O in Spinal Cystern
If there is cont'd leakage of CSF which can't be replenished fast enough = brain -sensitive structures.
Dilation (widening) of the veins in the brain after procedure
Severe headache --> specific cause unknowno
Severe lower limb pain --> Damage to nerves (peripheral nerves) in the cauda equine
(lower lumbar, sacral, coccygeal), but they can regenerate bc peripheral nature
o
Complications after LP:
Lumbar Puncture (Spinal Tap)
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2ND ORDER NEURONS CROSS TO OPPOSITE SIDE (CONTRALATERAL) SIDE OF BRAIN AT MIDLINE
OF MEDULLA = Internal Arcuate Fibers
From pons onward = "Medial Lemniscus Pathway"
2nd order neurons synapse at VENTRAL POSTEROLATERAL (VPL) NUCLEUS OF THALAMUS
THIRD ORDER
Project to postcentral gyrus via post limb of internal capsule --> SOMESTHETIC SENSORY
AREA (AREAS 3, 1, 2) in cortex
Thalamus
Discriminative touch, vibration, stereognosis, conscious proprioception
Input from: Paccinian & Meissner's corpuscles, joint receptors, muscle spindle & GTO
Anterior spinothalamic pathway --> light touch, pressure, tickle, itch
Lateral spinothalamic pathway --> pain, temperature
Anterior --> have crossed & uncrossed fibers
Posterior --> uncrossed fibers only
Spinocerebellar pathway -->proprioceptors to cerebellum
Cuneocerebellar pathway --> unconscious proprioception
Every sensation has to reach the thalamus before reaching the higher center (exceptOlfactory)
Discriminative General Senses --> carried by dorsal column
FIRST ORDER
Fasciculus gracilis (medial) carries
sensory from LOWER LIMB
Fasciculus cuneatus (lateral) carries
sensory from UPPER LIMB & THORAX
Dorsal Root Ganglion (DRG) --> SPINAL CORD
SECOND ORDERF gracilis synapses at GRACILE NUCLEUS
F cuneatus synapses at CUNEATE
NUCLEUS
Medulla Oblongata
TOUCH ON LEFT SIDE GOES TO RIGHT SIDE OF BRAIN
Tumor at C5 --> affects dorsal column tract = loss of discriminative general senses at &
below C5 on IPSILATERAL side
Lesion at Fasciculus Gracilis --> flaccid paralysis in lower trunk & lower limb
Lesion at Fasciculus Cuneatus --> spastic paralysis (weakness in muscle tone) In upper
IfRIGHT MEDIAL LEMNISCUS is damaged = loss of discriminative sensation on LEFT side
If damage on RIGHT SIDE OF T11 = lose sensation on SAME side below T11
Damaged sensory nerve pathways (posterior funiculus)
Lesions in parietal lobe = astereogenesis on CONTRALATERAL side
DDx: ask patient to close their eyes and identify a familiar object in their hand
Astereogenesis: inabili ty to discriminate bt objects of different shapes, textures, weight &
size based on just touch
Clinical Scenarios
Dorsal Column - Medial Lemniscus PathwayMay-17-10
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Loss of balance when person is standing straight w/ feet together
Conditions affecting dorsal columns of spinal cord
Conditions affecting sensory nerves (CN VII)
+ve = sensory ataxia (ie: loss of proprioception)
Can't use test bc even when eyes are open, these patients can't stand straight
-ve = cerebellar ataxia (ie: localized cerebellar dysfunction); vestibular disorder
Romberg sign: neurological test used to assess dorsal columns of spinal cord - essential for
proprioception & vibration
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Lateral Spinothalamic Tractlocated in lateral column carries PAIN & TEMPERATURE sensations
Caused by cell injury orpotentialcell injury (ie : increased prostaglandins)
Indicates if there is something wrong with specific organ (ie: internal injuries)
Pain:noxious stimuli or unpleasant sensation; protective mechanism
Pain receptors: free nerve endings -NEVER adapts
Thickly myel inated fibers
Sharp & pricking pain
Latency period is very short-->NOT blocked by morphine
Very well localized
Less emotional = pain is not inhibited
Neospinothalamic Tract
Fast Pain carried by Group III (A) fibers
Dull, burning sensation
Slow onset -->CAN be blocked by morphine be fore pain reaches maximum
Diffuse (poor localization)
Emotional, autonomic response = can inhibit pain
Paleospinothalamic Tract
Slow Paincarried by Group IV (C) fibers
We don't take pain k ille rs for small pains
Analgesic Systemw/in body to maintain pain
Rubbing painful area will give temporary relief of pain sensation
When emotions are running high, pain systems are inhibited
Pain is inhibited by the body
Spinothala
mic TractAudio recording started: 9:18 AM May-18-10
Anterior, Post & Lateral Horn cells
Each lamina corresp to cel ls
Lateral Spinothalamic Tract
= pain pathway
Divided into many 10 laminas
Gray Matter of the Spinal Cord
You have to stop the pain sensation be fore it reaches the cortex
"Gate" is located in the posterior horn cell of the SPINAL CORD
T cells releases SUBSTANCE P - allows pain sensation to ascend
If release of substance P is blocked = inhibition of pain system
SG cells inhibitT-cells --> can't release Substance P --> pain can't ascend
Rubbing painful area rel ieves pain bc the collaterals of the thickly-myelinated, touch fibers stimulate
SG cells & T cells
Thinly-myelinated fibers inhibit SG cells and stimulate the T-cells
Gate Control Theory of Pain Sensation (Melzak, 1965)
Transection of lateral spinothalamic tract = CONTRALATERAL loss of pain & temp below lesion (pain isn't
completely lost bcspinoreticular pathwayalso carries pain)
Lamina 2: Substantia Gelatinosa Rolando (SGR)
Spinothalamic TractMay-18-10
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Audio
RecordingAudio recording started: 9:11 AM May-19-10
Pain perceived in area #43
Very rich in SEROTONIN
Magnus Raphae Nucleus in pons
Substantia Gelatinosa Rolando in spinal cord
1970 - endogenous morphine-like substances found (ie: enkephalin & endorphins)
Collaterals given from pain system to periaqueductal grey matter as system ascends which is connectedto Magnus Raphae Nucleus--> SGR --> release Serotonin (Descending Pain Inhibiting System)
Magnus Raphae Tractbt MRN & SGR = release of Serotonin from MRT & release ofENKEPHALIN from
SG cells = inhibits release of P-substance from Tcells
Opiate-binding receptor substances found in Periaqueductal Grey Matterin MIDBRAIN
When emotions are very high, stimulates Periaqueductal Grey Matter--> stimulates MRN --> releases
Serotonin --> SGR --> release Enkephalin - -> block P-substance
Insufficient blockage of P substance in normal conditions, but when emotions are very very high, the
whole pain system is blocked
Analgesics stimulate the Periaqueductal Grey Matter
Enkephalins INHIBIT P-substance
If pain system doesn't reach the cortex --> don't feel pain at all
Taking pain killers all the time decreases the sensitivity of the nuclei
Pain kil lers not needed for every little thing bc body will take care of itself
Somatic Pain felt in affected organ
Visceral Pain felt in superficial somatic structure (referred pain)
Diaphragm pain is felt in neck region (Dermatome C3, C4)
Gall Bladder pain is felt in back
Heart pain felt in shoulder region
Deeper diseased viscera & superficial somatic structure are derived f rom same dermatome
Every organ does NOT present referred pain (this theory doesn't completely explain)
Dermatomal Rule: during devl't, the deeper diseased viscera (ie: septum transversum) has carried
its inhibition f rom the higher region (ie: septum transversum descends from neck region)
1.
Higher brain center perceives pain in superficial somatic structure instead of viscera (is not
explained completely either)
Convergence: pain from superficial somatic structure & deeper diseased viscera synapse in spinal
cord next to each other (synapses converge in same segment) then ascend via pain system
2.
Facilitation:pain from superficial somatic structure gives off a collateral in spinal cord which
facilitates stimulation so that the higher brain perceives pain from superficial (but still doesn't
explain why brain doesn't perceive visceral pain)
3.
3 Theories: A combination of these theories explain Referred Pain
Referred Pain: Pain in deeper diseased viscera is felt in the superficial somaticstructure
Damage to area #43 doesn't affect sensation because there is BILATERAL INPUT
If you damage Area #43 on one side, you DO NOT lose pain & temperature sensation!
Pain comes from amputated limbs
Performed if pain ki llers aren't helping
If this sti ll presents in pain, must amputate limb (ie: in diabetic patients)
Selective Risotomy: take out few fibers of dorsal nerve root --> pain doesn't reach spinal cord
Each part of the body is received by its specific segment in Area 43 of cortex
That part of the cortex has learned where it i s receiving pain sensation from
Compression of neuromasses leads to stimulation in cortex = perceives pain in that region
If limb has been amputated, the cut ends of the nerves get entangled = Neuromass
Sensory Projection Law
Phantom Limb Pain
Descending Pain Inhibiting SystemMay-19-10
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Audio recording started: 9:21 AM May-20-10 Audio
Recording
Carry unconscious proprioception for Lower Limb & Lower part of the TrunkAscend to Cerebellum
Has to be faster so that body can prepare for mov't
These tracts conduct impulses at a faster rate than any other tract in the body (125 m/s)
Receptors are proprioceptors/stretch receptors in muscle fibers (ie: Golgi Tendon)
First order neurons in DRG
Clark's Column of Cells only present from T1-L2
Also receives fibers fromGroup Ia & II from muscle spindle
First order touch fibers give off collaterals to Lamina 7in Clark's Column of Cells (Nucleus Dorsalis)
Fibers cross on the same side of the spinal cord & ascend up through length of spinal cord
2nd order fibers collaterals of touch pthwy from Nucleus Dorsalis become Spinocerebellar Tract
Dorsocerebellar (DSCT):unconscious proprioception from spinldles via Group Ia & II
Ventrocerebellar
Spinocerebellar TractMay-20-10
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Audio recording started: 11:15 AM May-25-10Audio recording started: 11:22 AM May-25-10
Audio
Recording
Anterior --> carries efferent copy
T1-L2 go to Clark's column of cells (Nucleus Dorsalis)
Spinocerebellar Tractcarries unconscious proprioception from lower limb
From upper l imb fasciculus cuneatus ascends up to medullaoblongata and
give collaterals to accessory cuneate nucleus (behaves like Clark's column)
Follow ICP to cerebellum
Cuneocerebellar Pathway(homologous to spinocerebellar pthwy)
Above C8there is NO Clarke's column of cells
1st ORDER: free nerve endings (Merkel's disk); in DRG --> Tcells
2nd ORDER: dorsal horn in Lamina 4-6, cross via Ant grey commissure &
travel up as Ant STT
3rd ORDER: from thalamus to Areas 3, 1, 2 in cortex
This pthwy allows for maintainance of light touch & pressure sensation
Ventral Spinothalamic Tract (light touch, pressure)
OTHER ASCENDING TRACTS
Audio
recording .. .
Fibers from visual pthwy reach Superior Colliculus of tectum of midbrain
Fibers from sound pthwy & cutaneous sensations also carried via this pthwy
When you pinch the skin on the neck (or squeeze trapezius) = slight dilation of
ipsilateral pupil
Spinotectal: visual reflexes
Cell bodies located in DRG & ascend in brain stem --> go IPSI or CONTRA and then
ascend to thalamus & hypothalamus then diffuses
If lateral spinothalamic pthwy is damaged; this pthwy still maintains pain sensation
Spinoreticular:diffused pthwy, carries PAIN =emotional response
Spinoolivary
Upper motor neurons: from cortex or brainstem to spinal cord
Once a reflex gets conditioned (ie: withdrawal reflex), depending on how strong the stimuli is
If someone gets any noxious stimuli =WITHDRAWAL & COUNTEREXTENSION REFLEXES
Reflexes are due to plasticity of nerve fibers (we have learned and kept the reflex)
Each measures about 25 m, thickly myelinated fibers
Conduct impulses at rate of115-120 m/s
Motor unit: single alpha-motor neuron divides to supply many
Supply striated muscle f ibers at motor end plate
Alpha-motor neurons = Final Common Pathway of Sherrington
Lower motor neurons
Anterior Column/Grey Matter/Horn cells: contains LOWER MOTOR NEURONS
Reflexes
Cuneocerebellar PathwayMay-25-10
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Larger motor unit: supplies 100s
Smaller motor unit: supplies ~5 muscle f ibers
striated muscle f ibers (ie: a single alpha-motor neuron can supply
100s of extrafusal muscle f ibers) = mass contraction or skil led activity
supplies many muscle fibers
Sometimes becomes purposeless because don't contract to
prerequisite length; contraction depends onmuscle spindles
Phasic alpha-motor neurons: heavy li fting (mass contraction)
only supplies few muscle fibers
Contract to prerequisite length of muscle contraction
Tonic alpha-motor neurons: skilled activity
Monosynaptic reflex loop from Group Ia fibers from muscle spindle andinfluence from higher center (suppression or inhibition)
Gamma-motor neurons
Beta-motor neurons
Brown-Sequerd Syndrome:hemisection of spinal cord
Bilateral loss of pain sensation
Ipsilateral loss ofdiscriminative general senses (DGS)
alpha motor neuron damage = flaccid paralysis
Gamma motor neuron damage = atrophy
Lower motor neuron paralysis
Ipsilateral loss ofunconsciousproprioception (DSCT)
At level of Lesion (T7)
Contralateral loss of pain sensation
Ipsilateral loss of DGS
Ipsilateral loss ofunconsciousproprioception (DSCT)
Below lesion
Normal pain sensation
Normal DGS
Above lesion
Ex: 32 yo male stabbed in the back at T7; no 2-point discrimination & no pain in right lower limb.
Which pathway was damaged? PAIN
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Audio recording started: 11:10 AM May-26-10 Audio
Recording
Monosynapticreflex loop from Group Ia fibers of muscle spindle
When you are flexing, you need to have inhibition of the extensors
Prevents excessive alpha-firing & may be antagonists
Strichnine (plant poison) inhibits these interneurons (Renshaw cells) = personwill die of convulsions
Renshaw cells --> INHIBIT adj alpha-motor neurons = inhibit the antagonistic muscles
As they supply striated muscle fibers, give collaterals to interneurons (many in grey matter)
Final common Sherrington Pathway
Alpha-motor neurons
supply intrafusal fibers (Nuclear bag & chain fibers) of muscle spindle (2-5 mm bundles) =
stretch receptors --> maintain muscle tone
Gama-motor neurons: less thickly-myelinated (10-25m) fibers; conduction = 10-45 m/s
Nuclear Bag Fibers
Nuclear Chain Fibers
Muscle spindles = 2-5mm inside muscle fibers = stretch receptors
Determined by muscle spindleMuscle tone: sustained muscle contraction (partial state of a muscle contraction)
Thinly - myelinated
Detect motion of muscle
Stimulation of1 = stimulate polar regions of nuclear bag fibers = stretch
Annulospiral nerve endings are non-contactile; when bag stretches, nerve
endings stimulated and info sent via Group Ia fibers to alpha-motor
neurons --> skeletal muscle fibers
Nuclear bag surr byAnnulo-spiral nerve endings = Group Ia fibers where it ends
Determines rate of change of contraction of muscle fibers
1 damage = lead-pipe rigidity
Parkinson's: 2 hyperactivity = cog-wheel rigidity
Dynamic (1):supply polarregion ofnuclear bag fibers --> Trail Endings
Static (2):supply polar region ofnuclear chain fibers --> non-contractile
Gamma motor neurons
Anterior
Horn Cells
5-10 mins of recording is missingAudio recording started: 11:46 AM May-26-10
Anterior Horn CellsMay-26-10
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Adaptation of change after contraction has happened
Group II fibers --> monosynaptic reflex loop to alpha fibers (extrafusal)
Gamma Reflex Loop
Constantly influenced by upper motor neurons
hyperactivity --> Clasp-knife rigidity = initial resistance followed by sudden
release
Lower motor neuron paralysis = ATROPHY bc intrafusal spindle becomes flaccid
Upper motor neuron paralysis = no atrophy
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Audio recording started: 11:05 AM May-27-10 Audio
Recording - 2
Areflexia: paralysis caused by damage to lower motor neurons
Supplementary motor cortex (area 4 & 6)
Area 3,1,2 contributes
Fibers descend thrucorona radiata
Pyramidal system: originate from giant pyramidal cells in 3rd layer of cortex
Extra-pyramidal system
Motor system
Lateral corticospinal Tract
Anterior corticospinal Tract
Giant cells of Bertz: found in precentral gyrus and in anterior paracentral lobule
Bell's Palsy:paralysis of contralateral lower side of face (along lip)
Ask patient to close eyes & resist while you try to open it --> i f patient can't resist
= paralysis of obicularis oculi (CN III)
If patient can wrinkle forehead =CN VII damage
Test for CNVII damage: ask patient to smile & check if l ips are aligned
Damage to area above brain stem --> Upper motor neuron damage
Damage in brain stem --> Upper & Lower motor neuron damage
Damage below brain stem --> lower motor neuron damage
Transection = spastic hemiparesis w/ Babinski sign
Corticospinal
Corticonuclear fibers pass thru genu of internal capsule after corona radiata
Some fibers synapse in cranial nerve nuclei (lower motor neurons) of brain stem &
descend downward
Most fibers synapse on contralateral cranial nerve nuclei of brain stem
Corticobulbar
Pyramidal System
Not from cortex, other parts of the brain instead
Standing erect ctrld by this system
Vestibulospinal Tract--> extensor tone
Olivospinal--> compares skilled activity
Responsible for cutaneous stimulation
Tectospinal Tract--> vision
Reticulospinal--> activity
Rubrospinal--> flexor tone
Extra-pyramidal System
Descending TractsMay-27-10
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Houses cranionuclei, EXCEPTOlfactory & Optic N
Cardiovascular & Respiratory Centers in LOWER MEDULLA OBLONGATA Reticular System
Constantly charging NTs to be awake
Sometimes you are so tired and unaware of surroundings bc less active
Lesions always lead to crossed systems (ie: loss of pain & temperature on RIGHT
side of face, but LEFT side of body)
If there is a lower motor neuron paralysis on left side of tongue and upper motor
neuron paralysis on right side of body
Vertigo:nausea & dizziness
Stroke: ischemia in brain (different classifications); neurological symptoms last
greater than 24 hours
Transient Ischemic Attack (TIA): symptoms last connected to cerebellum
Brain Stem
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Audio recording started: 11:25 AM May-28-10
Medulla
Oblongata
Capital punishment -->when you break the atlantoaxial joint = crushes odontoid process of axis &
cardiovascular centers in medulla obl
Motor derived from basal lamina
Sensory derived from alar lamina
Contains cranial nerve nuclei
Piriform-shaped structure; length ~3cm & max transverse diam in cranial part ~2cmUpward continuation of spinal cord at
Horizontal line just above att of 1st pair of cervical nerves; approximately crosses
middle of odontoid process of axis (C2)
Spinomedullary junction: Junction bt medulla & spinal cord
Cranial nerves that emerge from horizontal line (medial to lateral): CN VI, VII, VIII
Medulla Oblongata
Abducens (VI) bt medial part of sulcus &
pons
motor part of Facial is more medial
than sensory (Nervous intermedius)
Facial (VII), & Vestibulocochlear (VIII) bt
olive & lower part of pons
Nerves emerge out from medial to lateral from
horizontal sulcus:
Ponto-medullary junction: horizontal sulcus bt
medulla & pons
Striae Medullare: separates pons from medulla
oblongata on posterior side
Pons
Internal Structure of Medulla Oblongata
Medulla OblongataMay-28-10
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Inferior
Superior
Crossed motor paralysis:
Affects majority of limb & trunk muscles on contra side due to UMN decussation
Cause ipsilat paralysis of cranial nerve due to lack of decussation (ie: 3, 6, 12 --> facial muscles
on ipsi side)
Unilateral lesion in brainstem affecting UMN & LMN
Infarction of medial part of medulla
Ipsilateral = hypoglossal nerve damage = deviation of tongue on same side
Loss of discrete touch, conscious proprioception, vibration (damage to medial
lemniscus)
Contralateral = limb weakness (corticospinal tract damage)
Inferior: Medial Medullary Syndrome (Dejeune syndrome)
Manifestation of decompression syndrome
Dmg to paramedian branches of post cerebral art or perforating arteries
Ipsilateral: occulomotor nerve palsy w/ drooping eyelidContralateral: corticospinal & corticobulbar tracts damage (UMN dmg & lower facial muscles
& tongue
Substantia nigra: contralateral parkinsonism
Superior:Weber's syndrome= occulomotor nerve palsy
Alternating Hemiplasia: ipsil ateral /contralat presentation in diff parts of the body
Internal Structure of Medulla Oblongata
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Audio recording started: 11:15 AM May-31-10 Brain Stem
Cont'd
Supraspinal Nucleus: part of central grey matter that is detached; descends down to C5
Lamina 2 of post grey column of spinal cord corresp to Substantia Gelatinoso Rolando (SGR)
Extended across entire length of medulla oblongata
Separatedfrom surface of medulla obl by Spinal Tract of Trigeminal Nerve
Spinal Nucleus of Trigeminal Nerve: in continuation with SGR; ends atPonto-medullary Junc'n
then continues with principle sensory nucleus of Pons
Pyramidal Decussation
Pyramids in ventral part --> corticospinal fibers (few corticobulbar)White matter --> ascending & descending tracts
Fibers from both cross = Internal Arcuate Fibers and then ascend as Medial Lemniscus
Grey matter -->Gracile Nucleus & Cuneate Nucleus
Sensory fibers are decussating
Fibers to all muscles of tongue except Palatoglossus & Styloglossus
Paralysis of genioglossus = tongue falls back --> closes oropharynx = death by
suffocation
Main bulk of tongue ctrld by Genioglossus ("li fe-saving" muscle bc protrudes
tongue to open airway)
Hypoglossal Nucleus: belongs to general somatic efferent (GSE) column
Cranial Nerve Nuclei appears here
Sensory Decussation
Ifspinal nucleus of damaged = loss of pain & temp from IPSILATERAL side
Iftrigeminal lemniscus damaged = loss of pain & temp from CONTRALATERAL
Alternating hemianesthesia --> loss of pain & temp ipsilaterally from
head/neck & contralaterally from body
Ifspinal lemniscus & trigeminal lemniscusdamaged in medulla
Clinical Scenarios
Pyramidal (Motor) Decussation of MedullaMay-31-10
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To test, ask patient to protrude tongue --> deviates to affected side
Injury to hypoglossal nerve =Lower motor neuron paralysis
Upper motor neuron lesions --> contralateral
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Audio recording started: 11:21 AM June-01-10
Sensory
Decussat...
Medial Zone suppliedby AnteriorSpinalA. -->4thpart of Vertebral A
Strokesin vicinity of Brainstem = devastatingeffects
Medialzone of medulla damaged= INFERIORCROSSEDMOTOR PARALYSIS (aka: InferiorAlternating Hemiplasia)
No atrophy
Hyperreflexia
Rigidity
Positive Babinsky Sign
Damage to corticospinal fibers from pyramid = UPPER MOTOR NEURON PARALYSIS, contralateral
If right side of pyramid damaged --> entire LEFT side of body paralyzed
Hypoglossal Palsy: fasciculus, atrophy, flaccid paralysis
Damage to Hypoglossal Nucleus = damage to IPSILATERAL tongue muscles
If you see tongue muscle involvement + effects on contralateral side of body = MEDIAL MEDULLARY SYNDROME
Damage of Medial Lemniscus --> lose CONTRALATERAL touch, vibration, pressure, stereognosis
Medial Medullarysyndrome= blockage of Ant spinal A
Clinical Scenarios
Sensory Decussation of MedullaJune-01-10
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3 zones --> Medial, Lateral, Intermediate
Efferents --> cerebellum = climbing fibers --> synapse w/ purkinje cells
Stereotypic skilled activity
Olive produced by Inferior Olivary Nuclear Complex--> corticoolivary & spinoolivary fibers
Medial lemniscus
Tectospinal tract
Medial Longitudinal Fasciculus (MLF): lesion can cause nystagmusCN XII nuclei (efferent column in Hypoglossal column) --> anterior-lateral sulcus
Medial Zone
Afferents: sensory motor cortex (corticool ivary fibers), red nucleus (rubroolivary fibers), spinal cord from
anterior & lateral column (Spinoolivary fibers)
Efferents: Inferior cerebellar peduncle --> cerebellum --> climbing fibers (on purkinje cells)
Supplies soft palate, vocal cords
Nucleus Ambigus: gives bronchomotor fibers to cranial parts of CN IX, X, XI --> efferent column
Dorsal Nucleus of Vagus: gives preganglionic PS fibers to heart, sm muscles of resp & alimentary canal &
glandular epith; located lateral to hypoglossal nucleus
Receives taste sensation from VII, IX, X (sensory nerves of tongue)
Nucleus of Tractus Solitarus: belongs to visceral afferent column (SVA)
Preganglionic PS fibers to parotid gland via CN IX
Inferior Salivatory Nucleus: belongs to visceral efferent column
Intermediate Zone
Lateral Zone -->Anything that lies beneath ICP
Section of Medulla at Level of Olive
Medulla
Oblongat...Audio recording started: 11:28 AM June-02-10
Ventral & Dorsal Spinocerebellar Tracts
Lateral Spino-thalamic Tract (Spinal Lemniscus begins at Pont-medul lary junc'n)
Damage to LEFT Spinal Nucleus of Trigeminal N --> loss of pain & temp from
LEFT side of face & RIGHT side of body
Damage to Spinal Lemniscus
Alternating Hemianesthesia: ipsilateral loss of pain & temp from face &
contralateral loss of pain & temp from rest of body
Ipsilateral Horner's Syndrome
Lateral Medullary Syndrome (Wallenberg's Syndrome): most common brain stem
syndromes;caused by hemorrhagic stroke, embolic stroke, tumors
Supplied by Posterior Inferior Cerebellar Artery (PICA)
Other Structures in Lateral Zone
Medulla Oblongata at Level of OliveJune-02-10
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Hypothalamus = head ganglion of autonomic sys
Lateral horn cell of spinal cord only from T1-L2 = preganglionic fibers of
sympathetic (White rami communicantes)
Partial ptosis: partial drooping of upper eye lid --> due to damage to
descending autonomic fibers
Myosis:constriction of pupil resulting from paralysis of dilator muscle of iris
Anhydrosis: no sweating from affected side (ipsilateral)
Enopthalmus: sunken eyeballs bc fat loculi in orbit are supplied by post-
ganglionic sympathetic fibers
Vasodilation= increased blood flow i n face & neck (flushing)
Dysphagia: diff iculty swall owing bc damage to Nucleus Ambigus --> all pharyngeal
muscles paralyzed
Hoarseness of voice: paralysis ofRecurrent Laryngeal (Vagus) --> Nucleus Ambigus
Ipsilateral Ataxiabecause of damage to inferior cerebellar peduncle
Decreased sensitivity to li ght touch due to damage to spinal nucleus of trigeminal
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Audio recording started: 11:20 AM June-03-10 Audio Rec...
Pons: bridge bt midbrain, medulla & cerebellum
External Features (Ventral)
PonsJune-03-10
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Audio recording started: 11:14 AM June-07-10 Pons Cont'd
Basilar Part of the PonsJune-07-10
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Audio recording started: 11:16 AM June-08-10 Pons Cont'd
Verticle fibers
Horizontal fibers
Ponti nuclei
Neurobiotaxis phenomenon --> Facial N loops around abducens nucleus
Dorsal to trapezoid body in tegmentum= chain of lemniscus system
Basilar Part of Pons at level of Facial Colliculus
Pons at level of Facial ColliculusJune-08-10
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Audio recording started: 11:10 AM June-10-10 Pons at
level of Tri ...
Just above the facial colliculus
Medial lemniscus (cell bodies in medulla)
Spinal lemniscus (cell bodies in dorsal horn of spinal cord --> Laminas 4-6
Trigeminal lemniscus
Lateral lemniscus (cell bodies in superior olivary nuclear complex (2o) & cochlear nuclei (3o))
Muscles of mastication; Masseter, temporalis, med & lat pterygoids, tensor tympani,
tensor veli palati, anterior belly of digastric
Bronchomotor fibers: from motor nucleus of trigeminal N --> joins the lateral thicker sensorypart of nerve --> trigeminal ganglion; supplies muscles derived from 1st pharyngeal arch
Pons at the Level of Trigeminal Nuclei
TEST 1 ON MONDAY JUNE 14
If Trigeminal N is intact, but can't feeltouch sensation during corneal reflex =
lesion in principal nucleus of pons in
brainstem
Pons at level of Trigeminal NucleiJune-10-10
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Usually unilateral damage
Hyporeflexia (NO ATROPHY)
Rigidity
Spasticity
Damage to corticospinal tract = contralateral hemiparesis of body (UPPER MOTOR
NEURON TYPE OF PARALYSIS)
Symptoms
Lower motor neuron type of Lateral Rectus paralysis --> medial strabismus (eye
will move to medial side)
Upper motor neuron type of paralysis on contralateral side of body --> loss of
proprioception & tactile pressure
Raymond's Syndrome (aka Alternating Abducens Hemiplasia): damage to Abducens
nucleus
ipsilateral LOWER MOTOR NEURON PARALYSIS of facial musculature
Contralateral UPPER MOTOR NEURON PARALYSIS of body
Miller-Gubler Syndrome (aka Alternating Facial Hemiplasia):
Medial Pontine Syndrome: results when shortcircumferential branches of Basilar A in pons are
damaged
Ipsilateral limb ataxia (due to damage to ICP)
Partial Ptosis
Myosis
Anhydrosis
Enopthalmus
Ipsilateral Horner's syndrome (due to damage ofdescending autonomic fibers)
Contralateral loss of pain & temp from body (damage to spinal lemniscus)
Ipsilateral loss of pain & temp from face (damage to spinal nucleus of trigeminal)
Lateral Pontine Syndrome:damage to long circumferential branches of Basilar A
Alternating Trigeminal Hemiplasia: paralysis of muscles of mastication
Hearing loss due to involvement of cochlear component of vestibulocochlear N
Ipsilateral Facial paralysis due to involvement of Facial Nerve (not nucleus)
Lateral Pontine Syndrome
Lateral Medullary Syndrome: Dysphagia, hoarseness of voice
How to differentiate bt Lat Medullary & Pontine Syndromes
Pontine Syndromes
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Audio recording started: 11:23 AM June-15-10 Midbrain
Shortest segment of the brainstem
Cerebral aqueduct of Sylvius: in center of midbrain, communicates the 3rd
ventricle to 4th ventricle; CSF flows through
Mamillary bodies w/in fossa
Interpeduncular fossa:between 2 peduncles
Quadrigeminal bodies ( Corpura quadrigemina)
2 pairs of colliculi (Inferior & Superior)
inferior brachium connects inferior colligate to MGB
Tectum (dorsal) = 4 elevations
Tegmentum
Occulomotor N (CN III) emerges from medial side
Trochlear N (CN IV) emerges from lateral surface of crus cerebri
Crus cerebri (ventral): crossed from above, downwards byoptic tract
Cerebral peduncles (2)diverge
Midbrain
Section of Midbrain at level of Inferior Colliculus
MidbrainJune-15-10
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Audio recording started: 11:10 AM June-16-10
Midbrain
Cont'd
Section at Level of Inferior Colliculus
Midbrain Cont'dJune-16-10
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Audio recording started: 11:11 AM June-17-10 Midbrain ...
Pair of Inferior & Superior Colliculi
Tectum of Midbrain
Afferentsfrom Lateral Lemniscus and from the opposite side of i nferior colliculus,MGB
via Inferior Brachium
Inferior Colliculi: responsible for auditory reflexes
Quadrigeminal bodies
Paramedian perforators of terminal Basilar APeduncular perforating branches of posterior cerebral A
CONTRALATERAL HEMIPARESIS OF BODY (UMN paralysis of corticospinal)
CONTRALATERAL HEMIPARESIS OF FACE (UMN paralysis of corticobulbar)
Damage of crus cerebri --> corticospinal & corticobulbar fibers
Lesion of crus cerebri of midbrain & Occulomotor Nucle ar Complex
Weber' s Syndrome (Ventromedial Superior Midbrain Syndrome)
Syndromes of the Midbrain
Signs of le sion: fi xed dilated pupil doesn't accommodate, ptosis devl'ps followed by a complete inte rnal ophthalmoplegia
(masked ptosis); unopposed lateral rectus = outward deviation of the e ye
Occulomotor Nerve (III) Nucleus: indirectl y innervated by corticobulbar tract
Signs of lesi on: diplopia due to weakness of downward & inward mov't, vertical diplopia
Trochlear Nerve (IV) Nucleus: indirectl y innervated by corticobulbar tract
Edinger-Wespal Nucleus
Midbrain
Signs of lesi on: weakness of jaw clenching & side to side mov't
LMN--> j aw deviates to weak side when mouth opened; fasciculation of temporalis & masseter
Mesencephalic
Trigeminal (V) Nucleus:directly innervated by corticobulbar tract
Pons
Cranial Nerve Nuclei in Brainstem
Midbrain @ Superior ColliculusJune-17-10
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Principal
Spinal
Can't look laterally; eye i s deviated medially bc unopposed action of medial rectus
Abducens (VI) Nucleus: indirectly innervated by corticobulbar tract
Signs of lesion: facial weakness
LMN--> f orehead paralyzed; due to Bell's palsy, oti tis media, skull fracture, cerebello-pontine angle tumors, parotid tumors,
Herpes Zoster (Ramsay-Hunt syndrome), Lyme dise ase
UMN --> spares the forehead, stroke, tumor
Facial (VII) Nucleus:directly innervated by corticobulbar tract
Cochlear Nucleus
Vestibular Nucleus
Signs: palatal weakne ss, nasal regurgitation, palate moves asymmetrically when patient says 'ah'; recurrent nerve pals y =
hoarsness, loss of vol ume (bovine cough)
Nucleus of Vagus (X)
LMN--> wasting ofipsilateral side of tongue, with f asciculation; on protrusion, deviates to affected s ide (but away from the
side of a centrallesion)`
Hypoglossal (XII) Nucleus: directly innervated by corticobulbar tract
Spinal nucleus of Trigeminal (V)
Nucleus Ambigus
Solitary Nucleus
Medulla
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Audio recording started: 11:09 AM June-18-10 Midbrain S.. .
"corticonuclear" fibers (f rom cortex to cranial nerve nuclei )
UMN --
LMN --> begins in neural axis ( ie: brain stem, spinal cord) and supplies target cells
Not all of the cranial nerves have LMNs
Olfactory, Optic, Ve stibulocochlear are purely sensory nerves (no motor component)
Motor nucleus of facial nerve supplie s face; lower part of nucleus suppl ies lower part
of the face, upper supplies upper part of face
Contralateralf acial palsy
Recall: Weber's Syndrome
Corticobulbar Fibers
Involvement of CN III
Hemichorea due to involvement of red nucleus &subthalamic nucleus
Ataxia & tremor due to involvement ofred nucleus
Ipsilateral CN III fascicular palsy
Paramedian perforators of terminal Basilar A, Interpeduncular branches of Posterior
cerebral A
Paineras syndrome?
Benedict's Syndrome (Paracentral Tegmental Superior Midbrain Syndrome)
Midbrain SyndromesJune-18-10
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Audio recording started: 11:13 AM June-21-10
External F.. .
Part of hindbrain; situated in the posterior cranial fossa w/ pons & medulla oblongata
4th ventricle cavity bt pons & cerebell um
"silent" area of the brain bc upon electrical stimulation, no conscious response
Ex: flex ion has to be stopped before extension can start
Timing of an action; if timing is off (i e: dysmetria) will overshoot or fall short when reaching
Smooth progression bt mov'ts - -> Compares actual mov't & intended mov't
Intensity/velocity of muscle contraction
Learns from mistakes (ie: playing a piano)
Responsible for
Plasticity of neuronal pools: ability to learn skil ls (ie: swimming, riding bike)
Motor cortex = planof action to cerebellum
Receives sensory info from periphery (ie: vi a spinocerebellar pthwy) andfrom motor cortex
Dysdidakhokinesia (Adidakhokinesia): absence of 2 alternating mov'ts
"organ of balance"
ICP (Restiform body) --> Medulla
MCP (Brachium pontis) --> Pons
SCP (Brachium conjunctiva) --> midbrain
Cerebellum connected to 3 parts of brain stem vi a cerebellar peduncle
Vermis: anatomical midline worm-like structure
Hemisphere: extend from vermis
Cerebellum
Divisions of Vermis
Lingula
Central Lobule
Culmen
Declive
Folium
Tuber
Pyramid
Uvula
Nodule
External FeaturesJune-21-10
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Audio recording started: 11:14 AM June-22-10
Cerebellum
Cont'd
Mossy fibers -->all other afferents
Climbing fibers --> All of the afferents from Inferior Olivary Nuclear Complex
All inputs i nto cerebellum can be classified into 2 types = excitation of cerebellum
Festigial Nucleusderives fibers from Vermis
Globus
Emboliformis
Nucleus Interpositus
Dentate Nucleus
Deep Cerebellar Nuclei
Outer = Molecular layer
Middle = Purkinje cell layer
Deep = Granular cell layer
Cerebellar Cortex = 3 layers
Internal Features of the Cerebel lum
Afferent fibers except inferior olivary input
2/3 of medullary center
Mossy fiber Rosette
Granular Cell Dendrite--> main afferent input
Synapse on granule cell dendrite; (GABA --> inhibitory)
Surrounded by astrocyte foot process
Golgi cell Axon
Afferent terminals on G RANULAR LAYER
Synaptic Glomerulus
Internal FeaturesJune-22-10
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Audio recording started: 11:15 AM June-23-10 Cerebellu...
Surrounded around 1 purkinje cell ; 30 million functional units
Purkinje fibers are the only output of cerebellar cortex
Functional Unit
Cerebellu...
Audio recording started: 11:21 AM June -23-10
Effect of Alcohol on Purkinje cells
Cerebellothalamic fibers from 3 deep nuclei to VPLo, VLc, CL
Cerebeloorubral fiber predominantly from Dentate nucleus & nucleus globusus
SCP
Fastigiovestibular fiber
ICP
Efferents of Cerebel lum (MAILY FROM SCP)
Cerebellum Cont'dJune-23-10
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Audio recording started: 11:15 AM June-24-10
Connection
s of the C...
Main Connections of the Vestibulocerebellum
Cerebellum & Automatic Motor Control
Functions of Cerebellum
Main connections of Paleocerebellum
Main connections of Neocerebellum
Pyramidal Tract & Associated Circuits
Connections of the CerebellumJune-24-10
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Maintenance of Equilibrium -- >balance, posture, eye mov't
Coordination of automatic mov't of walking & posture maintenance --> posture, gait
Motor learning = motor skil ls
Cognitive Function
Decomposition of mov't--> breaking down a smooth muscle act into a number of jerky
awkward component parts
Dysmetria(past-pointing): inabil ity to arrest muscular mov't at desired point
Dysdiadochokinesia (Adidydakokinesia):inability to perform rapid alternating mov'ts (rapid
supination & pronation of hands)
Normally, when flexors are working, we need to have a gradual release of extensors
If extensors stop immediately = jerky mov't
If flexors are not inhibited upon extension = rebound phenomenon
Rebound phenomenon of Holmes
Ataxia: incoordination of mov't; gait ataxia, truncal ataxia, titubation
Intention tremor: dysmetria that occurs during a voluntary action
Nystagmus:form of dystaxia consisting of to -and-fro eye mov'ts (ocular dysmetria)
Malignant; most common in vermis; originate from granular layer of cereb cortex
Obstruct passage of CSF = hydrocephalus
Archicerebellar lesion --> medulloblastoma
Paleocerebellar Lesion --> gait disturbance
Neocerebellar Lesion --> hypotonia, ataxia, tremor
Disorders
If there is a lesion in vermis = truncal ataxia
Paravertebral lesion = gait ataxia
Lateral zone lesion = incoordination = tremor
Arnold Chari Malformation: tonsils are el ongated & pushed down thru foramen
magnum --> blocks flow of CSF
Herniation of cerebellar tonsils --> chiari malformation
Action/intention tremor:dysmetria that occurs during a voluntary mov't
Caused by alcohol abuse = atrophy of rostral vermis
Gait, trunk, & leg dystaxia
Anterior vermis syndrome: leg region of anterior lobe
Result of brain tumors in children; caused by medulloblastomas or
ependymomas
Truncal dystaxia
Posterior vermis syndrome: flocculonodular lobe
Arm, leg, trunk & gait dystaxia
Cerebel lar signs are ipsilateral to lesion
Hemispheric syndrome:from brain tumor or abscess
Lesions of each division of cerebellum
Cerebellum
Intra-axial f ibers of Oculomotor nerve roots
Corticobulbar tracts --> contralat weakness of lower face (VII ), tongue (XII), palate (X)
Corticospinal tracts --> contralat hemiparesis of trunk & extremities
Weber's Syndrome:occlusion of posterior cerebellar A & aneurysm of circle of Will is
Complete ipsilateral oculomotor nerve paralysis
Eye abduction & depression bc unopposed action of LR (CN VI) & SO (CN IV)
Paralysis of le vator palpebrae =severe ptosis
Complete internal ophthalmoplegia = ipsilateral fixed & dilated pupil
Occulomotor nerve roots (intra-axial)
Contralateral cerebellar dystaxia w/ intention tremor
Red nucleus & dentatorubrothalamic tract
Contralateral loss of proprioception, discriminative tactile se nsation & vibration
sensation from trunk & extremities
Medial lemniscus
Benedikt Syndrome:occlusion or hemorrhage of paramedian midbrain br of post cerebral A
Complete Occulomotor palsy --> direct & indirect light reflex
Have to have alternating syndromes for it to be midbrain lesion
Midbrain
Results from lesions of MLF in dorsomedial pontine tegmentum; affect 1 or both MLFs
Sign of MS
Medial rectus palsy on attempted lateral gaze
monocular nystagmus in abducting eye w/ normal convergence
Lesions of CN VI = all MLF si gns & lateral rectus paralysis w/ internal strabismus
Internuclear opthalmoplegia (INO)aka MLF syndromePons
Dorsal Tract -->unconscious proprioception from lower extremitiesvia ICP
Ventral tract --> unconscious proprioception from lower extremitiesvia SCP
Spinocerebellar pathway
+ve --> sensory ataxia = loss of proprioception
-ve --> cerebellar ataxia = ve stibular disorder
Rhomberg's sign: loss of balance when subject stands w/ feet together & closes the eye s
MUST KNOW FOR TEST TOMORROW
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Audio recording started: 11:14 AM June-29-10 Test 2
Purkinje cells are only output from cerebellar cortex (A)1.
Left lower lid drooping , left angle of mouth sagging & saliva dripping; patient can't close eyes &
difficulty exposing teeth on left side; lesion involves? Facial nerve; Lower motor neuron paralysis (B)
2.
Flocculus & nodules = balancea.
Cerebellum ctrls balance by controlling vestibular nucelib.
c.Juxtarestiform body is an important link in this pathwayd.
How cerebellum controls balance (which is NOT correct)3.
Spastic paralysis on left upper & lower limbs, loss of fine touch & proprio in upper & lower body on left,
flaccid paralysis of lateral rectus. Where is lesion? Right side of pons
4.
Tremor is involved with lateral zone not cerebellum
Lesion in flocculonodular lobe & festigial nucleus does NOT produce none of the above5.
Blurred visiona.
Hyperacusis (paralysis of stapedius - facial nerve)b.
Inabili ty to chew (muscles of mastication)c.
Inabili ty to feel face (trigeminal)d.
Inabili ty to shrug shoulder (spinal part of accessory)e.
Inabili ty to close right eye, weakness in right orbicularis oculi (facial nerve), other symptoms?6.
IIIa.
IVb.
Vc.
VId.
Sudden onset of headache at night, complete ptosis on left, eye l ies down and out with fixed di latedpupil; which cranial nerve involvement
7.
8.
Test 2June-29-10
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Audio recording started: 11:32 AM June-29-10
Basal
Ganglia
Subcortical masses of gray matter (inner core)
Lentiform nucleus = biconvex mass of gray matter in concavity of internalcapsule
Caudate Nucleus = C-shaped grey matter
Medially --> Caudate nucleus, Lentiform nucleus
Internal capsule divides corpus striatum into 2 components
Corpus Striatum: largest component of the basal nuclei
Clostrum
Subthalamic Nucleus
Amygdaloid complex
Stereotyped activity
Subcortical center for extra-pyramidal pathway
Reticulospinal
Tectospinal
Vestibulospinal
OlivospinalRubrospinal
Influences LMN of brainstem & spinal cord via
Pyramidal pathway (corticospinal, corticobulbar) --> skillful voluntary act ofdistal musculature of
distal part of limbs (ie: hands, feet)
Area #6 = cortical center for extra-pyramidal pathway; Supplementary Motor Area
Extra-pyramidal pathway are multineuronal & multisynaptic pathways -->proximal part of
limb --> responsible for initiating action (ie: when writing, your shoulder needs to move first)
Classified into 2 types: Hypokinetic, Hyperkinetic
Akinesia --> no mov'ts
Bradykinesia
Hypokinetic
Parkinson's disease: also falls in hypokinetic category (worse)
Choreas -->Huntington's, Syndenham's
Hemiballism
Athetosis
Hyperkinetic
Basalganglia disease --> lose initiation of skilled voluntary act of proximal distal musulature
Direct & Indirect Pathway of Basal Ganglia
Basal Nuclei
Basal GangliaJune-29-10
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Basal
Ganglia C...
Audio recording started: 11:10 AM June-30-10
Principal afferents from 3 sources
Corticostriate fibers from CORTEX
Thalamostriatal fibers from Venteroanterior, Venterolateral THALAMUS
Nigrostrial fibers from SUBSTANTIA NIGRA
Amygdalostrial fibers from AMYGDALOID
Connections to Striatum
Striopallidal fibers: Most of efferents go to Globus pallidus externum
Strionigral fibers: Some go back to Substantia Nigra
Connections FROM Striatum
Lesion in CORPUS STRIATUM (probably in Putamen)
Complication of Rheumatic fever; usually recovers spontaneously in 1-4 mo
Fine, disorganzined, random mov'ts of tongue, face & extremities
Accompanied by muscular hypotonia
Exaggeration of assoc mov'ts
Common in children
Syndenham's Chorea
Lesion in Corpus Striatum (esp CAUDATE NUCLEUS) & Cerebral Cortex
Autosomal dominant (chromo 4); fatal
Insidious onset: usually 30-50 yrs
Choreic mov'ts assoc w/ emotional disturbances
Grotesque gait & severe ..
Dementia only results if there is involvement w/ cerebral cortex
Huntington's Chorea
Lesion in SUBTHALAMIC NUCLEUS
Commonly as a result ofcerebrovascular accidents (ie: stroke)
Mov'ts are cont's & exhausting, but cease during sleep
Can be fatal due to exhaustion
Can be ctrld by phenothiazines & sterotaxic surgery
Hemiballism
Lesion in SUBSTANTIA NIGRA (pars compacta)
Difficult to stop mov'ts once activity initiated
Can't express feel ings in face (masked face)
Resting tremor
Cog-wheel rigidity
Parkinson's Disease (Paralysis Agitans)
Hyperkinetic Disorders
Basal Ganglia Cont'dJune-30-10
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Audio recording started: 11:21 AM July-05-10
CerebrumCerebrumJuly-05-10
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Audio recording started: 9:06 AM July-06-10 Lobes of
the Cereb...
Lesions of motor cortex = contralateral spasatic paralysis of the body
Afferents from Area 3,1,2 via commissural fibers (association fibers)
Efferents =corticospinal & corticobulbar fibers
Primary Motor Cortex (Area 4)
Premotor Cortex (Area 6)
Frontal Lobe
Lesion of prefrontal cortex = lose initiative, carelessness, euphoria, vulgarity
Mental illness treated w/ bi lateral prefrontal lacotomy (not as common today) = behavioral changes
Excessive blood flow to prefrontal cortex also produces same problems (unknown reason)
Frontal LobeJuly-06-10
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Audio recording started: 11:15 AM July-07-10
Parietal Lobe
Over 1/5 of total cortex
Primary somatosensory
Secondary somatosensory
Gustatory
Association
Features
Involves association areas of cerebral cortex
Association areas are responsible for info processing bt sensory input & motor output
Cognition: abili ty to pay attention to identify & plan meaningful responses to external stimuli or internal
motivations
If vigorously ask if the l imb is there, then they wi ll admit it
Frequent consequence of stroke on right side of brain = neglect everythi ng on left
NOT blindne ss --> Patients can recognize & name objects
Doctor wiggle s a finger --> patient sees the fi nger, but if the doctor doesn't move the finger,
patient is oblivious --> they don't pay attention to left side
If there is damage to left side, you wil l never have neglect to right side bc paying attention is
function of dominant hemisphere (right brain)
Parietal (Contralateral) neglect syndrome: if lesi on on right side, can't recognize anything on the left (ie:
neglect anything that is on the left of patient)
Parietal Association Cortex: paying attention to complex stimuli
Temporal Association Cortex: identification of stimuli
Frontal Association Cortex: planning responses
Inputs are different from the rest of cerebral cortex
does NOT receive direct inputs from sensory organs
Inputs refle ct highly processed sensory info from other areas of the cortex
Area 22: Sensory Speech Area (Wernicke's speech area): forms words & sentences,
Association Cortex
Parietal LobeJuly-07-10
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Abil ity to speak via fibers connected to Areas 44 & 45 --> Motor Spee ch Area (Broca's)
comprehension of spoken word
Area 41 & 42: hear the words and sends stimul i to Area 22
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Audio recording started: 11:34 AM July-08-10 Cerebrum
Cont'd
Motor programs for speech production
Projects to motor cortex areas controlling vocal cords, tongue & lips
"nonfluent", "motor","Boca's"aphasia--> agrammatical,nonfluent speech.
Lesion causes expressive aphasia w/ poor articulation, short sentences, slow speech
Broca's area (44 & 45): motor speech center (located in inferior gyrus)
Hemisphere w/ language = dominant hemisphere (most commonly left hemisphere)
Language Areas of the Brain
Global Aphasia-->damage todominanthemisphere
If damagedominanthemisphere before6 years old= transferof language toNON-DOMINANT
Language AreasJuly-08-10
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Test 3 Key
Audio recording started: 11:16 AM July-13-10
Parkinson's disease1.
Cog-wheel rigidity2.
Lateral pontine doesn't include tongue paralysis3.
Efferent fibers from cerebellar to deep nuclei are axons from purkinje cells4.
Transverse section has E-W and red nucleus5.
Muscles of mastication are paralyzed (damage to motor nucleus of trigeminal) and can't feel
texture of food wi ll also have loss of tactile pressure on right face
6.
Proprioceptive info from lower body is NOT mainly carried by SCP (b)7.Parkinson's8.
Bradykinesia, rigidity, resting tremor (all of the above)9.
Substantia nigra10.
c11.
GABA everywhere except corticostriate (glutamate) D12.
Lentiform nucleus = putamen & globus pall idus13.
Left neglect = lesion in Parietal lobe14.
Left neglect = Right parietal cortex15.
c16.
Given17.
e18. All deficits are NOT contralateral to lesion (D)19.
Ventral spinocerebellar pthwy in SCP20.
Impaired comprehension & repetition = Wernicke's (B)21.
Normal fluency, comprehension, impaired repetition = conduction aphasia (D)22.
Impaired fluency, comprehension & repetition = global 23.
Impaired fluency, repetition, comprehension intact = broca's (A)24.
Chromosome 4 for Huntingtons25.
Answers
Test 3 Key
Audio recording started: 11:26 AM July-13-10
Test 3 KeyJuly-13-10
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Audio recording started: 11:46 AM July-13-10
Occipital
Lobe
Extended along calcaranean sulcus
Lunate sulcus posteriorly
Receives temporal half of same side of vision & nasal half of opposite side
Afferent from LGN
Lacks ability to analyze and discriminate
Anterior part --> Peripheral vision
Posterior part --> Macular vision
Occlusion of posterior cerebral artery
Macular vision spared due to presence of collateral blood supply from middle
cerebral A
Lesion =homonymous hemianopsia
Area 17: Primary Visual Cortex
Analyzes & discriminates new images vs past images
Area 18: Parastriate cortex
Area 19: Peristriate cortex
Occipital Eye Field
Superior longitudinal bundle between area
Area 18 & 19 connected toSuperior Colliculus for scanning mov'ts and protective measures
via Tectobulbar pathway
Corticotectal fibers from Area 18 & 19
Area 18 & 19 receives info from bilateral Area 17 (can analyze & discrimination)
Processing of color, mov't direction (scanning mov'ts), visual interpretation
Can't recognize a face you have already met
Vision is normal
Alzheimer's --> lose abili ty to recognize familiar faces (no facial recognition)
Lesion to Area 39 = visual agnosia (can't identify images that have been seen before)
Area 18 & 19 efferent to Area 39 (higher association visual cortex)
Association cortex: storage of past visual images
Visual Lobe
We always move body parts opposite to mov't of eyeball
Ex: flinching if something thrown towards you
Vestibuloccular Reflex
Occipital LobeJuly-13-10
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Audio recording started: 11:36 AM July-14-10 Cerebrum
Cont'd
Fibers are predominantly from pyramidal cells and stellate cells of cortex
Enables us to react to sensory input
Short association fibers (aka cortical U-shaped fibers) --> connect adjacent gyri
Superior longitudinal bundle: connects frontal eye fie ld (Area 8) to occipital eye fi eld (Area
18 & 19) w/in same hemisphere
Arcuate fasciculus: between Area 22 (Wernicke's) & Area 44, 45 (Broca's)
Cingulum: bundle which becomes most important part ofPapez Circuit(memories)
Long association fibers
Association fibers: comm w/ adjacent gyri (ie: bt Area 3,1,2 & Area 4)
Intermingle w/ commissural fibers (anterior commissure & corpus callosum)
Cont's w/ internal capsule, downwards
Corona radiata: project from vicinity of corpus striatum
Corticopetal fibers: fibers that go INTO cerebral cortex
Corticofugal fibers: fibers that go OUT of cerebral cortex
Continuous upwards with corona radiata
Continuous downwards with crus cerebri of midbrain
Anterior Limb
Genu
Posterior Limb
Sublentiform part & Retrolentiform part
Internal capsule: highway for afferents & effe rents of cerebral cortex
Neo-cortical: from neocortex
Fimbria derived from hippocampus
Allo-cortical: from old cortex
Projection fibers: project beyond the cerebrum (afferents & efferents)
Commissural fibers
White Matter
White MatterJuly-14-10
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Audio recording started: 11:11 AM July-15-10 Cortical
Connectio...
Corticospinal fibers (upper limb, trunk, lower limb)
Corticobulbar fibers
Lesion =contralateral hemiparesis of body
Anterior 2/3
If these f ibers are intact does NOT = complete paralysisCorticorubral fibers
From ventral anterior & midline nucleus of thalamus to Area 4 & 6
Superior thalamic radiation fibers
Corticostriate fibers
Fasciculus thalamicus
Posterior 1/3
Posterior Limb
Internal Capsule
Connect identical area of one hemi to the opposite hemi across midline (most are
homotopical, but few are heterotopical - go to diff areas)
5 sets of commissural fibers
Anterior Commissure
Posterior Commissure
Hippocampal CommissureHebelunar Commissure
Connects almost ALL the identical areas to opposite hemisphere EXCEPTprimary
somasthetic sensory area of hand (3,1,2) & primary visual area (Area 17)
Language, analytical, clinical thinking, intellectual ability, calculations
95% of population is left hemisphere dominant
Spatial arrangements, artistic skil ls, musical abilities, non-verbal abilities
Non-dominant hemisphere (right)
These areas are also in opposite hemisphere, so info is sent via corpus
callosum, but one side is stil l dominant
Language areas: Broca's (44, 45), Wernicke's (22), Area 29, 40
Learned expression --> left hand will know what right hand is doing
Writing = upper part of Area 6 (Supplementary Motor Area)
Cut corpus callosum to prevent series of traffic between hemispheres (ie: severe
epilepsy) -->split brain preparations
Corpus Callosum (~300 mill ion fibers)
Commissural Fibers
Cortical Connections Cont'dJuly-15-10
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Audio recording started: 11:18 AM July-16-10 Thalamus
Mass ofgray matter split in between 3rd ventricle
3rd ventricle: cavity in midline
extends from inter-ventricular foramen (of Monroe) to upper end ofcerebral
aqueduct
Divides i nto 2 parts:hypothalamus (below) & (epi)thalamus(above)
Hypothalamic sulcus: runs in middle of diencephalon
Sagittal section
Diencephalon
If thalamus doesn`t function a pin-prick sensation becomes a highly unbearable pain
sensation; music that you normally like becomes highly unbearable
All sensory modalities integrated in thalamus EXCEPTOlfaction
Thalamus
ThalamusJuly-16-10
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Audio recording started: 11:14 AM July-20-10
Diencephalo
n Cont'd
Thalamus
MGB --> auditory fibersLGB --> light
VA & VL --> motor function
VPL/VMP --> somatosensory (ie: VPL receives pain & temp)
SpecificRelayNuclei -->receive specificsensations
Pulvinar/Lateral Posterior Complex
Lateral Dorsal (LD)
Connected to pre-frontal cortex & amygdaloid complex
Dorsal medial (DM) --> emotions; depth of emotions/tone of feelings
Association Nuclei --> no specifi c projections, associated w/ emotions
Part of VA
Cenromedian nucleus
Reticular nucleus
Parafollicular nucleus
Intralaminar --> Important for ARA system
Non-specific--> no specific function, but is associated (ie: DM related to prefrontal cortex)
Diencephalon Cont'dJuly-20-10
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Ependymal-lined (columnar epith l ining) cavities where produc'n of CSF occurs
4th ventricle = cavity ofhindbrain
Posteriorly--> cerebellum
Ventrally--> upper part of medul la & pons
Diamond-shaped space
Superior angle -->comm w/ 3rd ventricle via cerebral aqueduct Inferior angle -->cont's w/ central canal
Foramen of Luschka --> CSF to pontine cistern
Run venteromedially --> cerebellar peduncle
2 lateral angles
4th Ventricle
Tent-shaped
Divides roof into upper & lower parts
Formed by converging fibers of SCP = superior medullary velumUpper part: nervous part
Ependyma
Tela-choroidae of 4th ventricle: double-layer of the pia mater
Lower part: non-nervous part
Extends dorsally -->Dorsal Recess of 4th Ventricle (at the midline), extends into
white core of the cerebellum
Cerebello-medullary cistern (akacysterna magna)
Foramen of Mazendie: aperture in midline of roof
Roof
Diamond-shaped
Upper part --> Pons
Lower part --> Medulla
Striae medullarae fibers in between pons & medulla
Median sulcus divides the floor into 2 halves; vertically
Extends from Superior fovea (surface depression) caudally to another surface
depression --> Inferior fovea (depression on lower half)
Facial colliculus elevation that is opposite to superior fovea
Medially -->Medial eminence
Laterally -->Vestibular Area
Sulcus limitans divides each half of the ventricle
Floor
Audio recording started: 11:24 AM July-21-10 Ventricles
3rd & 4th VentriclesJuly-21-10
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Inter-thalamic space (in midl ine)Comm w/ lateral ventricle via interventricular foramen of Monroe
Comm w/ 4th ventricle via cerebral aqueduct
Formed by Tela choroideae of 3rd ventricle = double layer of pia mater
Fornix (choroid fissure bt thalamus and fornix)
Choroid plexus from lateral ventricle extends into 3rd ventricle via choroid fissure
Roof
Optic chiasma (most anterior)
Tuber cenarium
Infundibulum
Mamillary body
Posterior perforated substance
Pituitary gland
Floor
Primitive cranial end of neural tube
Anterior commissure:connects 2 olfactory areas
Lamina Terminalis invaded by anterior commisssure
Sloping area & 2nd column can't be seen (uvula between these columns)
Body of Fornix divides into 2 columns
Uvula: Small extension of 3rd ventricle beyond its space bt diverging columns of fornix
Anterior Wall
Hebelunar Commissure: thickening connecting 2 hebelunar nuclei
Upper part of stalk
If dmgd (ie: due to enlarged 3rd ventricle) --> no indirectl ight response
Posterior commissure --> pretectal f ibers for indirect light reflex
Lower part of stalk
Pineal gland att to wall via Pineal stalk(ventricle extends into stalk, dividing it into 2 parts)
Partially formed by tectum of midbrain
Posterior Wall
Lateral Wall (2)
3rd Ventricle
Contains modified neurons & astrocyte-l ike cells surr by fenestrated capillaries
Chemoreceptor Trigger Zone (CTZ): triggers vomiting in response to circulating emetic
substances
Plays a role in food intake & cardiovascular regulation
Area Postrema: 2 small subependymal oval areas on either side of 4th ventricle
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Audio recording started: 11:11 AM July-26-10 Ventricles
Cont'd
Cavity of forebrain (Telencephalon) --> inverted C-shaped
Roof: corpus callosum
Medial Wall: septum pallucidum
Laterally -->head of caudate nucleus
Medially -->rostrum of corpus callosum
Floor:
Anterior Horn (frontal lobe) --> body projects forwards and lateral
Roof & Lateral Wall: retrolentiform part of internal capsule - -> fibers of optic radiation & tapetal fibers (don't
interdigitate w/ corona radiata)
Bulb: elevation formed by Forceps majorfibers from splenium of corpus callosum
Floor & Medial Wall :
Posterior Horn (occipital lobe) --> tail-like extension of body
Calcaralis elevation at junc'n bt posterior & inferior horns
tail of caudate nucleus --> continuous w/ amygdaloid complex
Striae terminalis fibers
Roof: covers medial & lateral side
hippocampus
Albius: white matter covering the hippocampus; has dentate gyrus
Collateral eminence: elevation produced by collateral sulcus in inferior surface of brain (classified as
complete sulcus)
Floor: covers medial & lateral side
Inferior Horn (temporal lobe) --> largest projection of body
pleasured area = part of limbic system
Bilaminar Septum Pallucidum: between both sides of lat ventricles; extends from inferior surface of corpus callosum
to body of fornix
"5th ventricle of the brain" bt 2 layers of septum pellucidum but NOT really a ventricle bc no ependymal lining -->
only has tissue fluid
Roof: formed by undersurface of body of corpus callosum
Striae terminalis - -> bundle of fibers = only efferent out of amygdaloid complex in groove between thalamus &
caudate nucleus
Thalamostriate vein also present in groove
Floor: thalamus in medial aspect & body of caudate nucleus in lateral aspect
Medial Wall: formed by septum pallucidum
May affect body of caudate nucleus --
Hydrocephalus --> extension of body of lateral ventricle
Body: extends from interventricular foramen of Monroe to splenium of corpus callosum
Lateral Ventricle
Very clear, colorless, odorless, water-like fluid (ultrafiltrate of plasma)
pH = 7.35, speci fic gravity = 1007, [protein] = 25 mg/dL (vs 1025 mg/dL in plasma)
very high [Na] & [Cl], low [K] & [Ca]
Lateral ventricle --> interventricular foramen of Monroe--> 3rd ventricle
3rd ventricle -->cerebral aqueduct --> 4th ventricle
4th ventricle - ->subarachnoid space
Formed by choroid plexus --> mainly in lateral ventricles, but also in 3rd & 4th ventricles
CSF Circulation
Lateral Ventricle & CSF CirculationJuly-26-10
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Impaired circulation & resorption of CSF
Aqueductal stenosis: most common cause; narrowing of cerebral aqueduct = enlargement of lateral & 3rd
ventricles bc lateral communicates with 3rd but comm bt 3rd & 4th is impaired
Blockage ofinterventricular foramen of Monroe
Obstruction ofcerebral cisterns (superior, cerebromedullary, lumbar, pontine, chiasmatic)
Obstructive (Non-Communicating): obstruction w/in ventricular system
Increased production of CSF due to choroid plexus papilloma
Venous thrombus: occlusion of outflow veins
Arachnoid villi inflammation: occlusion of arachnoid granulations
Subarachnoid hemorrhage: compression of outflow veins
Decreased reabsorption into venous system
Non-Obstructive (Communicating)
Sluggish pupil lary reaction
Absence of upward gaze
Impaired lateral gaze, nystagmus
Paralysis or spasm of convergence
Absence of visual fixation
Seizures
Optic N compressed due to increased CSF
Impairment of venous f low = impairment ofcentral retinal artery
Exopthalmos --> optic disk is choked --> Optic Nerve (CN II) is submerged in subarachnoid space
Scleral prominence from downward displacement of orbits
UMN signs
Children
HA, Lethargy, Malaise, Incoordination, Weakness
Ocular nerve palsies
Most commonly caused by brain tumors, subdural hematoma, hydrocephalus
Usually doesn`t alter visual acuity or result in visual field defects
Usually asymmetric & greater on side of supratentorial lesion
Foster-Kennedy Syndrome:results from meni ngioma of olfactory groove --> compresses olfactory
tract & optic nerve = ipsilateral anosmia, optic atrophy &contralateral papilledema
Papilledema (choked disk): noninflammatory congestion of optic disk caused by increased intracranial P
Ataxia
Corticospinal tract anomalies, UMN signs
Adults
Signs
Symptoms in adolescence or adult life --> headache, neck pain
NO Hydrocephalus
Type I: displacement of cerebellar tonsils into cervical canal
Elongation of 4th ventricle
Displacement of inferior vermis, pons & medulla into cervical canal bc there is a congenital
absence of the roof to the 4th ventricle
Type II: progressive hydrocephalus & myelomeningocele
Chiari malformation
Developmental failure of roof of 4th ventricle during embryogenesis
90% have hydrocephalus --> Enlarged occiput
Dandy-Walker Syndrome: cystic expansion of 4th ventricle in posterior cranial fossa
Tumors
Lesions or malformations of posterior fossa
IVH
Meningitis: Pneumococcal, TB
Intrauterine infections
Causes
Abnormally narrow aqueductus of sylv ius
Endangers body of caudate nucleus
Obstruction of cerebral aqueduct = enlargement of 3rd & lateral ventricles
Aqueductal stenosis (congenital stenosis of cerebral aqueduct)
Aqueductal gliosis: brisk, glial response of ependymal lining
Pathology
Hydrocephalus
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Audio recording started: 11:09 AM July-27-10
Hydrocepha
lus
Bleeding in subependymal germinal matrix w/ or w/o ext into ventricles & brain
parenchyma (if w/ ext'n = communicating hydrocephalus)
Intravascular
Vascular
Extravascular
Pathology
Hydrocephalus (20% in moderate bleeds, 65-100% in large bleeds)
Complications
Avoid prolonged labor or difficult vaginal delivery
Avoid pneumothorax
Avoid hypo- or hypertension in neonate
Avoid hypoxic ischemic insult
Prevention
Children: Irritability, Poor feed, Lethargy, vomiting
Older pts: headache, change in personality, academic deterioration
Symptoms
Anterior fontanelle is wide open & bulging, increased head circumference
Dilated scalp veins
Sun-setting sign --> downward deviation of the eyes; occurs whenever there
is increased volume of head
Brisk tendon reflexes, spasticity
Clonus, Babinsky sign
Macewen sign "cracked-pot" --> enlargement
Prominent occiput (Dandy-Walker)
Signs
Separation of sutures
Erosion of posterior clinoids
Increased convolutional markings (beaten silver appearance)
X-ray plain films
Ultrasound
CT scan
MRI
Imaging studies
Medical:Acetazolamide, Furosemide
Surgical: V-P shunt placement
Therapy
Increased risk for developmental disabilities
Lower mean IQ compared to general population
Memory abnormalities
Some patients may show aggressive or delinquent behavior
Strabismus
Visuospatial abnormalities
Decreased visual acuity
Visual field defects
Visual problems
Patients require long term follow up (multidisciplinary)
Prognosis
Intraventricular Hemorrhage (IVH)
Hydrocephalus of ex-vacuo --> increased CSF w/o increasing intracranial P (occurs in
Alzheimer`s patients) = atrophy of brain
Causes of Hydrocephalus Cont`d
Diagnosis of Different Types of Hydrocephalus
Hydrocephalus Cont`dJuly-27-10
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Scored from 3 to 15 (3 = worst, 15 = best)
1 = no eye opening
2 = painful eye opening
3 = eye opening to verbal command
4 = eyes open spontaneously
Best eye response =max score of 4
1 = no verbal response
2 = incomprehensible sounds3 = inappropriate words
4 = confused
5 = orientated
Best verbal response =max score of 5
1 = no motor response
2 = painful extension
3 = painful flexion
4 = withdrawal from pain
5 = localized pain
6 = obeys command
Best motor response =max score of 6
3 Parameters
Glasgow Coma Scale Tool (GCS):quantifies level of consciousness after traumatic brain
injuries (steth not required)
Case 1
Abscess in right occipital lobe
With complaints of headache & a history of chronic ear infections, a 43 yo man was diagnosed
w/ papilledema, left homonymous hemianopia, altered mental status. There were no other
significant motor or sensory findings.
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Audio recording started: 11:10 AM July-28-10 Spinal Cord
Lesions
Case
Causes: stab/gun shot injuries, ext ramedullary tumorsaffe cting side of
spinal cord; herniation of disc (aka spinal shock)
Above lesion --> no problems
LMNbc Common Pathway of Sherrington damaged
Atropy, areflexi a, atonia
At level of lesion
LCST --> hyperreflexia, spasticity
Reticulospinal tract (tone)- -> clasp-knife rigidity
UMN -->mainly dmg to l ateral corticospinal tract
Below lesion
Motor deficits
Above lesion
BILATERAL loss of pain & te mperature (syringomyelia)
At level of lesion
Ipsilate ral loss of touch, pressure, vibration &
conscious proprioception -->Rhomburg's sign (+)
Contralateral loss of pain & temp
Below lesion --> cdamage to poste rior column tracts
Sensory deficits
Symptoms
Complete Hemisection of spinal cord (Brown-Sequard Syndrome)
A 23 yo woman complained of pain in her right breast & progressive we akness of
her right lower li mb for many months; neuro exam = weakness in low er limb; assoc
w/ spasticity (increased tone), hy perreflexia (increased deep tendon re flexes) at
knee & ankle = clonus; right side = loss of 2-ot touch vibratory sense & proprio at
leve ls below hip. Le ft side showed a loss of pain & temp below dermatome T7
Syringomyelia --> LISTEN TO LECTURE
Syrnix --> cavity (can enlarge in any direction = differing symptoms)
MRI is only way to confirm diagnosis along w/ PE
Conus medullaris
Amyeotropic lateral sclerosis (ALS)
Multiple sclerosis
Quada Inguina
Bilateral loss of pain & temperature sensation
Injury above leve l of Phrenic N (C3,4,5) = DEATH due to resp arrest
Anything bel ow C3,4,5 = alive
As bladder is fill ed w/ urine until it reaches max tone, internal urethral
sphincter opens a little = dribbling (retention reflex)
Urinary incontinence (can't ctrl LMN to bladder) = no micturiti on reflex
Retention of fe ces in rectum (retention outflow)
Gunshot injury below cervical region
Bed sores --> skin ulcers
RECOVERY PERIOD AFTER SPINAL SHOCK = 2-4 WEEKS
In cases of Spi nal Shock:
Spinal Cord LesionsJuly-28-10
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Audio recording started: 11:11 AM July-29-10
Limbic
System
Series of structures around brain stem; medial side of brain
Emotions referred by lower centers (ie : hypothalamus) to cortex (consciousness)
"smell brain" = forebrain
Humans are microosmatic bc our forebrain is responsible for more functions not just
smell
Smell enhances GIT motility
Enhances sex search (more important in animals)
Enhances fear...
1837 --> R. Owen -->Rhinencephalon (entire forebrain = olfactory in macroosmatic
animals, ie: dogs)
Limbic System
Papez Circuit--> responsible for recent memories and past experiences
Peripheral fibers = receptors
Central process pierces cribriform plate of ethmoid bone --> bulb
Olfactory mucosa --> in roof of nasal cavity (bipolar)
Mitral Cells
Tufted Cells
Bulb (6 layers)
Medial olfactory gyrus: gray matter that accompanies striae
Few fibers pass through Ant. Commissure --> opposite side ofcortex
Some fibers end up below/sub-callosum -->paraterminal gyrus
Medial Striae --> traverses w/ ant commissure & goes to opposite side
Intermediate Striae --> anterior perforated substance
Lateral olfactory gyrus: Band of gray matter that
accompanies striae; continuous with gyrus ambience
Both gyri continuous with Entorhinal Area (Area 28) --> part
of parahippocampal gyrus (part of corticomedial division of
amygdaloid complex)
Pyriform lobe
Lateral Striae --&