SF2 NBME / Misc Flashcards
Lentiform Nucleus (components)
Putamen + Globus Pallidus
Nerves of Corneal Reflex
V1 -> VII
Spina Bifida Occulta.
(Neural Tube Defect) Failure of caudal neuropore to close, but no herniation. Usually seen at lower vertebral levels. Dura intact.
Associated with tuft of hair or skin dimple at level of bony defect
Structures passing through Jugular Foramen
CN IX, X, XI, and Jugular Vein
Pathological Location of Serotonin Synthesis
Raphe Nucleus
Developmental Origin of PNS Neurons and Schwann Cells
Neural Crest
Athetosis
Slow, snake-like, writihing movements; especially seen in fingers
Characteristic of Basal Ganglia lesion + Huntington’s Disease
First Order Neuron: Lateral Corticospinal Tract
UMN cell body in the Primary Motor Cortex. Descends ipsilaterally (through posterior limb of internal capsule). Most fibers decussate at Caudal Medulla. Descends CONTRALATERALLY
Preoptic Nucleus
Regulate thermoregulation and sexual behavior. Releases GnRH.
Senses and Location: Ruffini Corpuscles
Pressure, slippage of objects of skin, joint angle change
Clinical sign: Anencephaly
Polyhydramnios (No swallowing center in brain). Fetus doesn’t swallow amniotic fluid
Lesion of Subthalamic Nucleus
Contralateral Hemiballismus
Cerebellar Tonsillar Herniation into Foramen Magnum
Coma and death result when these herniations compress the brainstem
Astigmatism
Abnurmal curvature of cornea. Different refractive power at different axes.
Correct with cylindrical lenses
Tonic-Clonic Seizure
Alternating stiffening and movement, postictal confusion, urinary incontinence, tongue biting
Myoclonic Seizure
Quick, repetitive jerks
Lissencephaly
Failure of neuronal migration resulting in a “smooth brain” that lacks sulci and gyri. May be associated with microcephaly and ventriculomegaly
Passage Through Cranial Cavity: CN XII
Hypoglossal Canal
Outer Ear
Visible portion of ear (pinna), includes auditory canadal and tympanic membrane.
Resting Tremor
Uncontrolled movement of distal appendages; termor alleviated by intentional movement
Substantia Nigra issue (Parkinson’s esp)
Myeleomeningocele
(Neural Tube Defect) Meninges AND neural tube (eg cauda equina) herniate through bony defect
Think about how Myelo- prefix sounds like myelin to remember this includes the neural tube herniating as opposed to Meningocele
Normal Pressure Hydrocephalus
Affects the elderly; idiopathic; CSF pressure elevated only episodically; does not result in increased Subarachnoid space volume.
Triad: Urinary incontinence, gait apraxia, and congnitive dysfunction “wet, wobbly, and wacky”
Lesion: Paramedian Pontine Reticular Formation
Ipsilateral gaze palsy (inability to look toward side of lesion)
(Primitive Reflex) Plantar Reflex
Dorsiflexion of large toe and fanning of other toes with plantar stimulation. (Babinski sign if present in adults - UMN lesion)
Dorsal Motor Nucleus
Sens autonomic (parasympathetic) fibers to heart, lungs, upper GI
CN X
Function: Lateral Spinothalamic Tract
Pain and Temperature
Vitamin B12 Deficiency (Spinal Cord)
Subacute Combined Degeneration (SCD)
Demyelination of Spinocerebellar Tracts, Lateral Corticospinal Tracts, and Dorsal Columns. Ataxic gait, paresthesia, impaired position/vibration sense.
Endoneurium
Thin, supportive connective tissue that ensheaths and supports individual myelinated nerve fibers.
Developmental predecessor to Telencephalon and Diencephalon
Prosencephalon
Synapse: Spinothalamic Tract
Synapses at level of entry
UMN or LMN: Spastic Paresis
UMN
Pathological Location of GABA Synthesis
Nucleus Accumbens
Name of Sympathetic Ganglion going to head
Superior Cervical Ganglion
Cerebellum: Deep Nuclei (lateral to medial)
Dentate, Emboliform, Globose, Fastigial
“Don’t Eat Greasy Food”
Input to Cerebellum
- Contralateral cortex via Middle Cerebellar Peduncle
* Ipsilateral Proprioceptive information via Inferior Cerebellar Peduncle from Spinal Cord
Decreased Mesocortical Pathway Activity
Leads to “negative” symptoms (eg anergia, apathy, lack of spontaneity). Antipsychotic drugs have limited effect.
Result of CN IV damage
Patient cannot look down and out. Eye rotated laterally. Difficulty walking down stairs. Head tilted.
Symptom: Damage to Short Ciliary Nerves
Mydriasis
Papilledema
Optic disc swelling (usually bilateral) due to increased ICP. Enlarged blind spot and elevated optic disc wtih blurred margins.
Synapse: Lateral Corticospinal Tract
Cell body of anterior horn
Internal Carotid Plexus
Post-Ganglion Fibers from Superior Cervical Ganglion (Sympathetics); Wrap ICA
Striatum (components)
Caudate (Cognitive) + Putamen (Motor)
Function: Anterior Spinothalamic Tract
Crude touch and pressure
Herniation associated with Epidural Hematoma
Uncal (Transtentorial)
Structures passing through Foramen Magnum
Brainstem, Spinal root of CN XI, and Vertebral Arteries
Asterixis
Extension of wrists causes “flapping” motion
Developmental Origin of Microglia
Mesoderm
Postganglionic Neurotransmitter in Parasympathetic Nervous System
Acetylcholine
Supraoptic and Paraventricular Nuclei
Synthesis Vasopression (ADH) and Oxytocin
Reflex Spinal Root: Patellar Reflex
L3, L4
Lucid Interval (Epidural Hematoma)
Epidural hematomas might present with transient loss of consciousness, a recovery period, and then rapid deterioration due to hematoma expansion
Myoclonus
Sudden, brief, uncontrolled muscle contraction
Craniopharyngioma
Most common childhood supratentorial tumor. May be confused with Pituitary Adenoma because both cause Bitemporal Hemianopia
Neurotransmitter Changes: Parkinson’s Disease
Increase: ACh
Decrease: DA, 5HT
Result of LMN Lesion of CN XII
1) Atrophy of Muscles
2) Protruded tongue deviates toward side of lesion
Medial Geniculate Nucleus
Input: Superior Olive and Inferior Colliculus of Tectum
Senses: Hearing
Destination: Auditory Cortex of Temporal Lobe
Neurotransmitter Changes: Depression
Decrease: DA, NE, 5HT
Inferior extent of Subarachnoid Space in Vertebrae
Lower border of S2
Huntington’s Pathology
Atrophy of caudate and putamen with ex vacuo ventriculomegaly. Neuronal death via NMDA-R binding and glutamate excitotoxicity
Increase: Dopamine
Decrease: GABA, ACh
Sensory Neurons: Free Nerve Endings
A∂ - Fast, Myelinated
C - Slow, Unmyelinated
“A Delta plane is fast but a taxC is slow”
Marcus Gunn pupil
aka Relative Afferent Pupillary Defect (RAPD)
When the light shines into a normal eye, constriction of both eyes if observed. When the light is then swung to the affected eye, both pupils dilate instead of constrict due to impaired conduction of light signal along the injured optic nerve
Postganglionic Neurotransmitter in Sympathetic Nervous System
Norepinephrine (exception sweat glands / ACh)
Parkinson’s Disease Pathology
Loss of dopaminergic neurons of substantia nigra pars compacta
Lateral Geniculate Nucleus
Input: CN II/chiasm/tract
Senses: Vision
Destination: Primary Visual Cortex
MRI Findings in Holoprosencephaly
Monoventricle and fusion of basal ganglia
Innervation: Outer Ear
- CN V3
- CN VII
- CN IX
- CN X
Cauda Equina Syndrome
Compression of spinal roots L2 and below, often due to intervertebral disc herniation or tumor.
Radicular pain, absent knee/ankle reflexes, loss of bladder/anal sphincter control, saddle anesthesia
Location of CSF flow in Meninges
Subarachnoid Space
Hormones controlled by Circadian Rhythm
1) ACTH
2) Prolactin
3) Melatonin
4) Norepinephrine
Tic Douloureux
Intense, stabbing pain. CN V or an be limited to single divisions of Trigeminal Nerve (Most Frequent: V2)
Catarct
Painless, often bilateral opacification of lens. Results in glare and decreased vision, especially at night.
Risk Factors:
- Age
- Smoking
- Excessive alcohol use
- Excessive sunlight
- Prolonged corticosteroid use
- Diabetes
- Trauma / Infection
Decreased Tuberoinfundibular Pathway Activity
Leads to increase in Prolactin secretion. Sexual dysfunction, galactorrhea, gynecomastia (in men), and decrease in libido
Kallmann Syndrome
Failure of GnRH-producing neurons (Preoptic Nucleus - Hypothalamus) to migrate from olfactory pit
Preganglionic Neurotransmitter in the Autonomic System (both Sympathetic and Parasympathetic)
Acetlycholine
Stroke causing Frontal Eye Field lesion
MCA Stroke
Epineurium
Dense connective tissue that surrounds entire nerve (fascicles and blood vessels)
Pinealoma
Tumor of Pineal Gland. Can cause Parinaud Syndrome (Compression of tectum -> Vertical gaze palsy); obstructive hydrocephalus (cerebral aquduct); Precocious puberty in males
Ependymal Cells
Ciliated simple columnar glial cells line the ventricles and central canal of spinal cord. Apical surfaces are covered in cilia (which circulate CSF) and microvilli (which help in CSF absorption). Specialized ependymal cells (choroid plexus) produce CSF
Innervation: Dilator Pupil
Sympathetics
Absence Seizure
3 Hz spike-and-wave discharges, no postictal confusion, blank stare
Notochord
Induces overlying ectoderm to differentiate into neuroectoderm and form neural plate
Retinal Vein Occlusion
Blockage of central or branch retinal vein due to compression from nearby arterial atherosclerosis. Retinal hemorrhage and venous engorgement. Edema in affected area
End level of Spinal Cord (Adault)
Lower border of L1-L2 vertebrae
Suprachiasmatic Nucleus
Regulate Circadian rhythm
Accomodation
Thickening of lens for near vision. Parasympathetics of CN III.
Output from Cerebellum
- Only output from Cerebellar cortex is Purkinje Cells (inhibitory)
- Deep Nuclei
Second Order Neuron: Dorsal Column Ascending Tracts
Decussates in Medulla. Ascends contralaterally as the Medial Lemniscus. Goes to VPL (Thalamus)
Cause: Leaking CSF through nasal cavity
Fracture of Cribriform Plate
Chromatolysis
Reaction of neuronal cell body to axonal injury. Changes reflect increased protein synthesis in effort to repair damaged axon.
1) Round Cellular swelling
2) Displacement of the nucleus to the periphery
3) Dispersion of Nissl substance throughout cytoplasm
Muscle(s) closing jaw
Masseter, teMporalis, Medial pterygoid
Pathological Location of Acetylcholine Synthesis
Basal Nucleus of Meynert
Central Poststroke Pain Syndrome
Neuropathic pain due to thalamic lesions. Initial paresthias followed in weeks/months by allodynia and dysesthesia on the contralateral side.
Chiari II Malformation
(Posterior Fossa Malformation) Herniation of Cerebellar Vermis and Tonsils through Foramen Magnum with Aqueductal Stenosis (Noncommunicating Hydrocephalus).
Usually associated with Lumbosacral Myelomeningocele (may present as paralysis/sensory loss at/below level).
Cell affected in Guillain-Barre Syndrome
Schwann Cell (demyelinating disease)
Anencephaly
(Neural Tube Defect) Failure of rostral neuropore to close. No forebrain, open calvarium.
Reflex Spinal Root: Cremasteric Reflex (Testicles move)
L1, L2
Brown-Sequard Syndrome (Name 5 Findings jackass)
Hemisection of Spinal Cord. Findings:
1) Ipsilateral loss of all sensation @ level
2) Ipsilateral LMN signs @ lesion
3) Ipsilateral UMN signs below lesion
4) Ipsilateral loss of proprioception, vibration, 2pt touch, and tactile sense below lesion
5) Contralateral loss of pain, temperature, and crude touch below level of lesion (spinothalamic)
If lesion above T1, may kill sympathetics
Dystonia
Sustained, involuntary muscle contractions..
Treated with BOTOX
Presbyopia
Aging-related impaired accommodation (focusing on near objects), primarily due to decreased lens elasticity, changes in lens curvature, and weak ciliary muscle. Patients need reading glasses often
Hemiballismus
Sudden, wild flailing of 1 arm and sometimes ipsilateral leg
CN V Motor Lesion
Jaw deviates TOWARD lesion due to unopposed pterygoid muscle
Lesion: Cerebellar Vermis
Truncal Ataxia, Nystagmus
Formed by Neural Plate
Neural Tube and Neural Crest Cells
Developmental origin of Anterior 2/3 of Tongue
1st and 2nd Pharyngeal arches
Pathological Location of Dopamine Synthesis
Ventral Tegmentum and/or SNc
Dopamine Receptor in Indirect Pathway
D2 Receptor
Decorticate Posturing
Flexion of upper extremities and extension of lower extremities.
Lesion above red nucleus
Wenicke-Korsakoff Syndrome
Confusion, Ataxia, Nystagmus, Ophthalmoplegia, memory loss (global), confabulation, personality changes
CAN O’beer
Passage Through Cranial Cavity: Opthalmic Artery
Optic Canal
Fracture which can cause Epidural Hematoma
Pterion (where the frontal, parietal, temporal, and sphenoid bones join together)
Tabes Dorsalis
Caused by Teritiary Syphilis. Results from degeneration/deyelination of Dorsal Columns and roots.
Progressive Sensory Ataxia (from proprioception).
Positive romberg sign and absent deep tendon reflexes. Associated with Charcot joints, shooting pain, Argyll Robertson pupils
Passage Through Cranial Cavity: Middle Meningeal Artery
Foramen Spinosum
Synapse: Dorsal Column Ascending Tracts
Nucleus Gracilis / Nucleus Cuneatus (ipsilateral medulla)
Lesion: Medial Longitudinal Fasciculus
- Impaired ADduction of ipsilateral eye
* Nystagmus of contralateral eye with ABduction
Developmental Origin of Posterior 1/3 of Tongue
3rd and 4th Pharyngeal arches
Essential Tremor
High-frequency tremor with sustained posture, worsened with movement or when anxious
Basal Plate
Neural structure on ventral neural plate. MOTOR
Wallenburg’s Syndrome
Lateral Medullary Syndrome. PICA.
Dysphagia, hoarseness, dec gag reflex, hiccups. Vomiting, vertigo, nystagmus, dec pain/temp sensation from contralateral body, ipsilateral face. ipsilateral Horner syndrome. Ipsilatareal ataxia, dysmeteria
Passage between 3rd and 4th ventricles
Cerebral Aqueduct of Sylvius
Cingulate (Subfalcine) Herniation under Falx Cerebri
Can compress ACA
Pathological Location of Norepinephrine Synthesis
Locus Ceruleus
Neurotransmitter Changes: Alzheimer’s Disease
Decrease: ACh
UMN or LMN: Flaccid Paralysis
LMN
Neurotransmitter Changes: Huntington’s Disease
Increase: DA
Decrease: ACh, GABA
Medial Medullary Syndrome
Infarct of ASA and/or Vertebral Arteries
Contralateral Payalysis (upper/lower limbs) Deficit of Contralateral proproception Ipsilateral hypoglossal dysfunction (deviates ipsilaterally)
Passage Through Cranial Cavity: CN II
Optic Canal
Pathologies which affect Oligodendrocytes
1) Multiple Sclerosis
2) Progressive Multifocal Leukoencephalopathy (PML)
3) Leukodystrophies
UMN or LMN: Weakness
Both
Nucleus Ambiguus
Motor innervation of pharynx, larynx, upper esophagus
CN IX, X, XI
Lewy Bodies
Composed of alpha-synuclein (intracellular eosinophilic inclusions in neuron body)
Decreased Nigrostriatal Pathway Activity
Leads to Extrapyramidal Symptoms (eg dystonia, akathisia, Parkinsonism, tardive dyskinesia)
Holoprosencephaly
Failure of the embyronic forebrain to separate into two cerebral hemispheres. Usually occurs during week 5-6. Maybe be related to mutations in Sonic Hedgehog Signaling pathway. Seen in Trisomy 13 (Patau) and Fetal Alcohol Syndrome
Moderate form: Cleft lip/palate
Severe: Cyclopia
Symptoms: Bell’s Palsy
- Facial Paralysis
- Drooling (Buccinator)
- Inability to Close Eye (Oribuclaris Oculi)
- Loss of Taste to Anterior Tongue
- Pain In/Behind Outer Ear
- Hyperacousia (Stapedius)
Difference in Symptoms: Acoustic Neuroma vs Parotid Tumor / Peripheral Damage
Acoustic Neuroma has all CN VII/VIII Symptoms. On the other hand…
Parotid Tumor/Peripheral Damage:
Only Facial Paralysis. No loss of taste, hyperacousia, decrease in secretion from glands, etc
Ciliary Ganglion
Parasympathetics of CN III.
Innervate: Ciliary Muscles and Sphincter (Constrictor) Pupillae
Causes of Ptosis
Damage to Sympathetics (see Horner’s Syndrome) or CN III (Levator Palpebrae Superioris)
Kluver-Bucy Syndrome
Disinhibited behavior (eg hyperphagia, hypersexuality, personality changes).
Bilateral lesion of Amygdala
Medulloblastoma
Most common malignant brain tumor in childhood. Commonly involves cerebellum.
Can compress 4th ventricle and cause Noncommunicating Hydrocephalus
Innervation and Function: Hyoglossus
Retracts and depresses tongue
CN XII
Neurotransmitter Changes: Schizophrenia
Increase: DA
Passage Through Cranial Cavity: CN VII
Internal Auditory Meatus
Huntington’s Disease
Autosomal dominant trinucleotide (CAG) repeat expansion in the Huntingtin gene on Chromosome 4.
CAG Repeats. CAG. Caudate loses ACh and Gaba
Posterior Nucleus (Hypothalamus)
Heating. Sympathetic
Complete Occlusion of Anterior Spinal Artery
Spares Dorsal Columns and Lissauer Tract
Mid-Thoracic ASA territory is watershed area, as artery of Adamkiewicz supplies ASA below T8. Aortic aneurysm repair can bring it on.
UMN deficit below the lesion (Corticospinal), LMN deicit at the level of lesion (anterior horn), and loss of pain/temp below the lesion (spinothalamic)
Passage Through Cranial Cavity: CN VIII
Internal Auditory Meatus
Jaw Jerk Reflex
Stretch reflex of Muscles that Close Mouth. Sensory/Motor V3
Masseter**
Temporalis
Medial Pterygoid
Anosmia
Loss of sense of smell
Ventral Posterolateral (VPL) Nucleus
Input: Spinothalamic and Dorsal Columns/Medial Lemniscus
Senses: Vibration, Pain, Pressure, Proprioception, Light Touch, Temperature
Destination: Primary Somatosensory Cortex
Major locations of CSF production
Lateral and Fourth Ventricles
Present with MS
- Acute Optic Neuritis (w/ Relative Afferent Pupillary Defect)
- Brainstem/Cerebellar syndromes
- Pyramidal tract demyelination
- Spinal Cord syndromes
Muscle(s) opening jaw
Lateral Pterygoid
Perfused by Lenticulostriate Branch of MCA
Basal Ganglia and Internal Capsule (Genu/Posterior Limb)
Sensory to Cornea
Long Ciliary Nerves (V1)
Open-Angle Glaucoma
Associated with age, Blacks, and family history. Painless, more common in U.S.
Senses and Location: Meissner Corpuscles
Dynamic, fine/light touch, position sense
Glabrous (hairless) skin
Glioblastoma Multiform
Highly malignant primary brain tumor found in the Cerebral Hemispheres.
Origin: Astrocytes
Intention Tremor
Slow, zigzag motion when pointing/extending toward a target.
Characteristic of cerebellar dysfunction
Ventral Lateral Nucleus (Thalamus)
Input: Cerebellum and Basal Ganglia
Senses: Motor
Destination: Motor Cortex
(Primitive Reflex) Sucking Reflex
Sucking response when roof of mouth is touched
Myeloschisis
(Neural Tube Defect) Also known as rachischisis. Exposed, unfused neural tissue without skin/meningeal covering
Chorea
Sudden, jerky, purposeless movements.
Seen in lesions of the basal ganglia. Huntington’s Disease
Alar Plate
Neural structure on dorsal neural plate. SENSORY
Passage between 4th Ventricle to Subarachnoid Space
- 2x Formina of Luschka (Lateral)
* Formina of Magendia (Medial)
Atonic Seizure
“Drop” seizures
Passage Through Cranial Cavity: CN V3
Foramen Ovale
Perineurium
Blood-nerve permeability barrier. Surrounds a fascicle of nerve fibers. Must be rejoined in microsurgery for limb reattachment.
Ossicles
Three bones in inner ear.
1) Malleus
2) Incus
3) Stapes
First Order Neuron: Dorsal Column Ascending Tracts
Enters Dorsal Root and Ascends Ipsilaterally (Fasciculus Gracilis/Cuneatus)
Second Order Neuron: Lateral Corticospinal Tract
Lower motor neuron leaves the spinal cord and onto the Neromuscular Junction
Anterior Nucleus (Hypothalamus)
Cooling. Parasympathetic.
(Primitive Reflex) Rooting reflex
Movement of head toward one side if cheek or mouth is stroked (nipple seeking)
Nucleus which CN VII, IX, and X relay taste sensation to
Solitary Nucleus (medulla)
Hypoxic Stroke
Due to hypoperfusion or hypoxemia. Common during cardiovascular surgeries, tends to affect watershed areas.
UMN or LMN: Fasciculations
LMN (spontaneous motor firing)
Communicating Hydrocephalus
Decreased CSF absorption by Arachnoid Granulations. Increased ICP, papilledema, and herniation
Friedreich’s Ataxia
Autosomal recessive trinucleotide repeat disorder (GAA) on Chromosome 8 in gene that encodes Frataxin (iron-binding protein).
Degeneration of lateral corticospinal tract, spinocerebellar tract, dorsal columns, and dorsat root ganglia. Staggering gait, frequent falling, nystagmus, dysarthria, pes cavus, hammer toes, diabetes mellitus, hypertrophic cardiomyopathy.
Neurotransmitter Changes: Anxiety
Increase: NE
Decrease: GABA, 5HT
Akathisia
Restlessness and intense urge to move.
Can be seen as a side effect of Parkinson’s treatment
Syringomyelia
Cystic cavity within central canal of spinal cord. Fibers crossin gin the Anterior White Commissure (SPINOTHALAMIC TRACT) are typically damaged first.
Occlusion in Locked-In Syndrome
Basilar Artery
(Primitive Reflex) Palmar Reflex
Curling of fingers if palm is stroked
Innervation and Function: Palatoglossus
Elevates posterior tongue during swallowing
CN X
CN XII Lesion
LMN. Tongue deviates toward side of lesion “lick your wounds”
Functions of Astrocytes
1) Physical support / repair
2) Extracellular K+ buffer
3) Removal of excess neurotransmitter
4) Component of blood-brain barrier
5) glycogen fuel reserve buffer
6) Reactive gliosis in response to neural injury
Function: Lateral Corticospinal Tract
Voluntary movement of contralateral limbs
Passage Through Cranial Cavity: CN I
Cribriform Plate
Epidural Space
Potential space between the dura mater and skull/vertebral column containing fat and blood vessels
Glaucoma
Optic disc atrophy with characteristic cupping, usually with elevated introcular pressure and progressive peripheral visual field loss if untreated.
Tonic Seizure
stiffening
Major Dopaminergic Pathways
1) Mesocortical
2) Mesolimbic
3) Nigrostriatal
4) Tuberoinfundibular
Developmental predecessor to Mesencephalon
Mesencephalon (HAH GOTCHA)
Reflex Spinal Root: Triceps Reflex
C6, C7
Lesion (Bilateral):Mammillary Body
Wernicke-Korsakoff Syndrome
Apex of basilar membrane
Low frequency (wide and flexible)
Parinaud’s Syndrome
Vertical gaze palsy, pupillary light-near dissociation, lid retraction, convergence-retraction nystagmus.
Lesion of Dorsal Midbrain.
Central Retinal Artery Occlusion
Acute, painless monocular vision loss. Retina cloudy with attenuated vessels and “cherry-red” spot at fovea. Evaluate for embolic source
Passage between Lateral Ventricles and 3rd Ventricle
Foramina of Monro
Test signs of Neural Tube defect
1) Elevated Alpha-Fetoprotein in Amniotic fluid and maternal serum (except spinal bifida occulta)
2) Elevated Acetylcholinesterase (AChE) in Amniotic fluid
Parkinson’s Symptoms
TRAPS
Tremor (Resting) Rigidity (Cogwheel) Akinesia (or Bradykinesia) Postural Instability Shuffling Gait
Phagocytic scavenger cells of CNS (mesodermal, mononuclear origin). Activation in response to tissue damage -> release of inflammatory mediatory (eg, nitric oxide, glutamate).
Microglia
Meningocele
(Neural Tube Defect) Meninges (but no neural tissue) herniate through bony defect
Senses and Location: Free Nerve Endings
Pain, temperature.
All skin, epidermis, some viscera
First Order Neuron: Spinothalamic Tract
Sensory Nerve Endings (A∂ and C) enter spinal cord
Decerebrate Posturing
Extension of upper and lower extremities
Lesion at or below red nucleus
Hypothalamo-Spinal Tract
Descending control of Autonomic Function
Visual results of Pituitary Adenoma and Craniopharyngioma (another cancer of the Pituitary)
- Press on Optic Chiasm
* Bitemporal Hemianopia
(Primitive Reflex) Galant Reflex
Stroking along one side of the spine while newborn is in ventral suspension (face down) causes lateral flexion of lower body toward stimulated side
Treatment for ALS / Lou Gehrig Disease
Riluzole “riLOUzole”
UMN or LMN: Atrophy
LMN
Dandy-Walker Malformation
(Posterior Fossa Malformation) Agenesis of Cerebellar Vermis leads to cystic enlargement of 4th Ventricle that fills the enlarged posterior fossa.
Associated with noncommunicating hydrocephalus and Spina Bifida
Second Order Neuron: Spinothalamic Tract
Decussates in spinal cord at the Anterior White Commissure. Ascends contralaterally to VPL (Thalamus)
Amyotrophic Lateral Sclerosis (Lou Gehrig Disease)
Combined UMN (Corticobulbar/Corticospinal) and LMN (medullary/spinal cord) degeneration. No sensory or bowel/bladder deficits.
LMN (Dysarthria, dysphagia, asymmetric limb weakness, fasciculations, atrophy); UMN, Pseudobulbar palsy (Dysarthria, dysphagia, emotional lability, spastic gait, clonus.
CN X Lesion
Uvula deviates AWAY from lesion.
Course of CN I into Nasal Cavity
Through Cribriform Plate of Ethmoid Bone
Risk Factors: Idiopathic Intracranial Hypertension
Female TOAD
Female, Tetracyclines (anti-biotics), Obesity, vitamin A, Danazol
Reflex Spinal Root: Anal Wink Reflex
S3, S4
Cape-like bilateral, symmetrical loss of pain and temperature sensation in upper extremities
Syringomyelia
(Primitive Reflex) Moro Reflex
“Hang on for life” reflex – abduct/extend arms when startled, and then draw together
Limbic Structures
- Hippocampus
- Amygdala
- Mammillary Bodies
- Anterior Thalamic Nuclei
- Cingulate Gyrus
- Entorhinal Cortex
Wallerian Degeneration
Disintegration of the axon and myelin sheath on distal side of axonal injury with macrophages removing debris
Proximal side of a neuron during axonal injury
Axon retracts and the cell body sprouts new protrusions that grow toward other neurons for potential reinnervation. Serves as a preparation for axonal regeneration and functional recovery
Conjunctivitis
Inflammation of the conjunctiva, leads to red eye.
Allergic - itchy eyes and bilateral
Bacteria - pus present
Viral - Most common, often adenovirus. Sparse mucous discharge, swollen preauricular node; self-resolving
Lesion: Cerebellar Hemisphere
Intention tremor, limb ataxia, loss of balance.
Damage to Cerebellum = Ipsilateral deficits
UMN or LMN: Increased Tone
UMN
Dopamine Receptor in Direct Pathway
D1 Receptor
Pituitary Adenoma
May be nonfunctioning (silent) or hyperfunctioning (hormone-producing).
Non-functional tumors present with Bitemporal Hemianopia (pressure on optic chiasm).
Uncal Transtentorial Herniation
Uncus = Medial temporal lobe
Ipsilateral blown pupil, contralateral hemiparesis. Later: coma
Multiple Sclerosis
Autoimmune inflammation and demyelination of CNS with subsequent axonal damage.
Senses and Location: Merkel Discs
Pressure, deep static touch (eg shapes, edges), and position sense.
Finger tips, superficial skin
Lateral Nucleus (Lateral Hypothalamic Area)
Hunger center. Stimulated by ghrelin and inhibited by leptin
Exceptions to Cranial Nerve Innervation Being Bilateral
Contralateral:
- Lower Face (CN VII)
- Genioglossus (XII)
- Trapezius (XI)
Ipsilateral:
* Sternocleidomastoid (XI)
Lesion causing Hemiballismus
Contralateral subthalamic nucleus
Mnemonic: Cranial Nerves - Sensory, Motor, or Both
Some Say Marry Money But My Brother Says Big Brains Matter Most
Base of Basilar Membrane
High frequency
Developmental predecessor to Metencephalon and Myelencephalon
Rhombencephalon
Nucleus Tractus Solitarius
Visceral Sensory Information
CN VII, IX, X
Structures passing through Superior Orbital Fissure
CN III, IV, V1, VI
Ventromedial Nucleus (Hypothalamus)
Satiety. Stimulated by leptin.
Function: Dorsal Column Ascending Tracts
Pressure, Vibration, Fine Touch, Proprioception
Spinal Muscular Atrophy
Congenital degeneration of Anterior Horn. LMN lesion.
Autosomal recessive mutation is SMN1.
Result of CN III damage
1) Lateral Strabismus
2) Ptosis
3) Mydriasis (dilated pupil - paralyzed pupillary constrictor)
Innervation and Function: Styloglossus
Draw up sides of tongue to create a trough for swallowing
CN XII
Location of Lumbar Puncture (Adult)
L3-L5
Damage: Lateral Nucleus (Lateral Hypothalamic Area)
Anorexia and failure to thrive (infants)
Developmental origin of CNS neurons, ependymal cells, oligodendrocytes and astrocytes
Neuroepithelia in the Neural Tube
Passage Through Cranial Cavity: CN V2
Foramen Rotundum
Stage of sleep sleepwalking, night terrors, and bedwetting occur
Stage 3
Result of CN VI damage
Medial Strabismus (Paralysis of Lateral Rectus)
Senses and Location: Pacinian Corpuscles
Vibration and pressure
Deep skin layers, ligaments, joints
Increase Mesolimbic Pathway Activity
Leads to “positive” symptoms (eg delusions, hallucinations. Primary therapeutic target of Antipsychotic drugs
Ventral Posteromedial (VPM) Nucleus
Input: Trigeminal and Gustatory Pathway
Senses: Face sensation, taste
Destination: Primary Somatosensory Cortex
Huntington’s Signs
- Chorea
- Athetosis
- Aggression
- Depression
- Dementia
Chairi I Malformation
(Posterior Fossa Malformation) Ectopia of cerebellar tonsils inferior to foramen magnum.
Congenital. Usually asymptomatic in childhood, manifests in adulthood with headaches and cerebellar symptoms. Associated with spinal cavitations (eg syringomyelia)
Reflex Spinal Root: Biceps/Brachioradialis Reflexes
C5, C6
CN XI Lesion
Weakness turning head to opposite side. Shoulder droop on side of lesion.
Notochord remnant in Adults
Nucleus Pulposus of Intervertebral Discs
Reflex Spinal Root: Achilles Reflex
S1, S2
Acute Closure (Glacuoma)
Ophthalmic emergency. Intraocular pressure pushes iris forward, angle closes abruptly.
Very painful, red eye, sudden vision loss, halos around lights, frontal headache, fixed and mid-dilated pupil, nausea, and vomiting. Mydriatic agents contraindicated.
Noncommunicating Hydrocephalus
Caused by structural blockage of CSF circulation within ventricular system
Embryological Germ Layers
Ectoderm, Mesoderm, Endoderm
Myopia
Nearsightedness. Eye too long for refractive power of cornea and lens. Light focused in front of retina.
Correct with concave lenses.
Production of Aqueous Humor
Produced by nonpigmented epithelium on ciliary body
Closed-Angle Glaucoma
Primary: Enlargement/anterior movement of lens against iris -> obstruction of normal aqueous flow through pupil -> fluid builds up behind iris, pushing peripheral iris against cornea and impeding flow through trabecular network
Secondary: Hypoxia from retinal disease induces vasoproliferation in iris that contracts angle
Innervation and Function: Genioglossus
Protrude tongue
CN XII
Hyperopia
Farsightedness. Eyes too short for refractive power of cornea and lens. Light focused behind retina.
Correct with convex lenses