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Hypothalamus functions

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TAN HATS Thirst/water balance Adenohypophysis control (ant. pituitary; derived from Rathke's Pouch) Neurohypophysis release hormones from hypothalamus Hunger Autonomic regulation Temperature regulation Sexual urges

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Posterior Pituitary + Hypothalamic Nucleuses + Functions

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Supraoptic nucleus: makes ADH (Lesions can cause diabetes insipidus) Paraventricular nucleus: makes Oxytocin

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Suprachiasmatic Nucleus

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Works with the pineal gland to secrete melatonin to maintain a functional circadian rhythm.

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Lateral Area of Hypothalamus

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Inhibited by Leptin Controls the feeling of hunger Destruction: anorexia; failure to thrive (infants)

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Ventromedial Area of Hypothalamus

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Stimulated by Leptin Controls the feeling of satiety/fullness Destruction (craniopharyngioma): obesity; hyperphagia

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Anterior Hypothalamus

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Cooling (senses ⬆Temp), pArasympathetic "AC Cools"

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Posterior Hypothalamus

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Heating (senses ⬇Temps), sympathetic Lesions can cause poikilotherm (cold-blooded)

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Dorsomedial Nucleus

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Controls aggression; animal instincts

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Arcuate Nucleus

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Controls the anterior pituitary functions: endocrine Produces DOPAMINE Inhibits prolactin secretion; lesions to the arcuate nucleus can result in: Galactorrhea+Amenorrhea

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Thalamus Function

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Major relay station for ascending sensory information

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Ventral Posterior Lateral (VPL)

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Input: Spinothalamic + Dorsal Columns +Medial Lemniscus (All ascending spinal tracts*) vpL; L for Long tracts Info: Pain/Temp + position + conscious proprioception Destination: 1º Somatosensory Cortex

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Ventral Posterior Medial (VPM)

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Input: Trigeminal and gustatory (taste) pathway vpM; M for medial/closer sensation Info: Facial sensation + taste Destination: 1º Somatosensory Cortex

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Lateral Geniculate Nucleus (LGN)

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Input: CN II Info: Vision (L: Light) Destination: Calcarine Sulcus (occipital lobe)

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Medial Geniculate Nucleus (MGN)

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Input: Superior olive + Inferior colliculus of pons Info: Hearing (M: Music) Destination: Auditory cortex of temporal lobe

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Mediodorsal Nucleus of Thalamus

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Function: Memory Lesions: Wenicke-Korsakoff syndrome if damaged

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Limbic System

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The 5 Famous F's (Feeling, Fighting, Fleeing, Feeding, F*cking) "Single Hippos with Mammillary Bodies Fornicate in September!" Single: Cingulate gyrus Hippos: Hippocampus MB: Mammillary Bodies Fornicate: Fornix September: Septal Nucleus

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Cerebellum Deep Nuclei

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"Don't Eat Greasy Foods" Lateral --> Medial Dentate Emboliform Globose Fastigial

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Basal Ganglia Functions

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Important in voluntary movements Receives cortical input, provides negative feedback to cortex to modulate movement Striatum: Putamen + Caudate N. Lentiform: Putamen + Globus pallidus

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Basal Ganglia Direct Pathway

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Stimulated by Dopamine (D1 receptor) Cortex ➜ Striatum ➜ Globus Pallidus Internus (Inhibited) ➜ Inhibitory Functions of GPi⬇ ➜ Thalams (+)... Resulting in the initiation of movement

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Basal Ganglia Indirect Pathway

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Stimulated by ACh/Inhibited by Dopamine (D2 receptors) Cortex ➜ Striatum ➜ Globus Pallidus Externus (Inhibited) ➜ Due to Inhibitory Functions of GPe⬇ ➜ Subthalamic Nucleus (STN) firing rate INCREASES (+) ➜ STN original stimulating effect on GPi is now INCREASED (+) ➜ GPi is stimulated ➜ GPi's inhibitory effects on thalamus is INCREASED ➜ movement inhibited as a result

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Parkinson's Disease

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Direct Pathway ⬇ Indirect Pathway ⬆⬆ Pathology: - Degenerative disorder of CNS - Lewy bodies (α-synuclein) - Substantia Nigra depigmentation - Dopamine/ACh imbalance - Loss of dopaminergic neurons Clinical Features: *TRAP* T: Tremor at rest (pill-rolling tremor) R: cogwheel Rigidity A: Akinesia (loss of voluntary movements) P: Postural instability

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Hemiballismus

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Direct Pathway⬆⬆ Indirect Pathway⬇ Pathology: - Contralateral Subthalamic Nucleus lesion (STN) - Lacunar stroke in a patient with history of hypertension - Loss of inhibition of thalamus through globes pallidus Clinical: "Half-ballistic like throwing a baseball" - Sudden, wilding flailing of 1 arm +/- leg

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Tourette Syndrome

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Indirect Pathway Abnormality Motor+Vocal tics; commonly associated with OCD/ADHD

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Wilson's Disease

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- AR Defect in copper transport - Accumulation of copper in brain/liver/eye - lesions in basal ganglia+cerebellar pathology Clinical signs: -Parkinsonian symptoms -Tremor; "wing-beating" -Fatty change of liver -Hepatitis of cirrhosis of liver

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Klüver-Bucy Syndrome

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Amygdala bilateral lesion Clinical signs: -Hyperorality (likes to put things in mouth) -Hypersexuality (or no sex drive at all) -Disinhibited behaviour

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Frontal Lobe Lesion

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Clinical signs: -Disinhibition -Deficits in concentration -Deficits in orientation -Deficits in judgement -Reemergence of primitive reflexes (ex: biting thumb) -Lack of 'planning the future'; depression

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R. Parietal Lobe Lesion

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Clinical Signs: -Spatial neglect syndrome -Agnosia of the contralateral side of the world Note: Agnosia -Difficulty in recognising sensations hence identifying things

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Mammillary Bodies (bilateral) Lesion

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Wenicke-Korsakoff Syndrome Wernicke - confusion, ophthalmplegia, ataxia Korsakoff - memory loss, confabulation, personality changes Aneurysms of PCA (posterior cerebral artery) can cause lesions to the MB; involved in medium term memory

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Cerebellar hemisphere lesion

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-Intention tremor -Limb ataxia -Ipsilateral deficits -Fall towards side of lesion

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Aphasia Types

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Broca's -Nonfluent aphasia with intact comprehension Wernicke's -Fluent aphasia with impaired comprehension Global -Nonfluent aphasia with impaired comprehension Conduction (Arcuate Fasciculus) -Poor repetition but fluent speech, intact comprehension

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Dorsal Column

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Ascending Pathway: Pressure, Vibrations, Fine touch, proprioceptive sensation Fasciculus cuneatus: Lateral bundle of DC; sensations of arms Fasciculus gracilis: medial bundle of DC; sensation of legs 1st Order Neurons: -Ascend ipsilaterally to nucleus cuneatus+gracilis and synapse 2nd Order Neurons: -Decussates in medulla -Ascends CONTRALATERALLY via medial lemniscus -Synapse at VPL of thalamus 3rd Order Neruons: Sensory cortex

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Spinothalamic tract

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Ascending Pathway: Pain + Temperature + Coarse Touch -Located at the anterior side of the spinal column 1st Order Neurons: -Enters dorsal root and synapses within the grey matter 2nd Order Neurons: -Decussates right away at anterior white commissure then ascents contralaterally -Synapse at VPL of thalamus 3rd Order Neurons: -Sensory cortex

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Corticospinal Tract

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Descending Pathway: voluntary movement of contralateral limbs 1st Order Neuron: -Upper motor neuron UMN from motor cortex -Descends ipsilaterally through internal capsule -Decussates at caudal medulla at the Decussation of Pyramids (Posterior Corticalspinal tract ONLY; Anterior corticospinal tract decussates at level of spinal cord) -Synapse at anterior horn of spinal cord level 2nd Order Neuron -Lower Motor Neuron LMN leaves spinal cord -PNS -Neuromuscular junction

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UMN Lesion

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Upper Motor Neuron lesions everything goes UP! Weakness (+) Reflexes (⬆) Tone (⬆) Babinski (+) Spastic paralysis (+)

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LMN Lesion

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Lower Motor Neuron lesions everything LOWERED Atrophy (+) Weakness (+) Fasiculation* (+) Reflexes (⬇) Tone (⬇) Babinski (-) Flaccid paralysis (+)

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Poliomyelitis

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Cause: poliovirus (fecal-oral route) Pathology: Anterior horn destruction leading to LMN destruction of the spinal cord Symptoms: -Malaise, headache, fever, nausea, abdominal pain, sore throat -Signs of LMN Lesion (flaccid paralysis; decreased tone+reflexes, fasciculations, fibrillations, etc) Findings: -CSF with lymphocytic pleocytosis with slight elevation of protein -No change in CSF glucose -Virus recovered from stool/throat

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Werdnig-Hoffmann Disease

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'Infantile spinal muscular atrophy' AR Inheritance Presents at birth as 'floppy baby' Tongue fasciculations Death around 7 months Associated with degeneration of anterior horns; LMN lesions only

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Amyotrophic Lateral Sclerosis (ALS)

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Cause: defect in superoxide dismutase 1 (SOD1) Pathology: LMN+UMN lesion signs with NO sensory, cognitive, or oculomotor deficits Clinical Signs: -Fasciculations and eventual atrophy; progressive and fatal -UMN+LMN Lesion signs Treatment: -Riluzole lengthens survival time

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Tabes Dorsalis

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Cause: 3º Syphilis Pathology: Dorsal columns degeneration bilaterally; resulting in impaired proprioception and locomotor ataxia Clinical signs: 3Ps (Pain, Paresthesia, Polyuria)** -Charcot's joints -Shooting (lightening pain) -Argyll-Robertson pupils ("prostitute's pupils"; reactive to accommodation but not to light) -Positive Romberg

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Brown-Séquard Syndrome

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Cause: Hemisection of the spinal cord Findings: 2 Ips + 1 Contra 1. Ipsilateral loss of proprioception+vibration+sensation from below lesion 2. Ipsilateral UMN signs below lesion (spastic paralysis) 3. Contralateral loss of pain+temperature from below lesion 4. At the level of lesion ipsilateral loss of all sensation+LMN signs If lesion occurs above T1 patient will present with Horner's Syndrome

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Horner's Syndrome

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PAM is HORNy P: Ptosis A: Anhidrosis M: Miosis Cause: associated with lesion of spinal cord above T1 (Pancoast's timor, Brown-Séquard Syndrome, late-stage syringomyelia) Lesion in the descending hypothalamic tracts will result in a central Horner's syndrome Lesion to the middle and superior cervical ganglions will result in peripheral Horner's syndrome

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Syringomyelia

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Cause: Damages of anterior white commissure of spinothalamic tract (2nd Order Neurons) Results: -Bilateral loss of pain and temperature sensation -Usually C8-T1 -Seen with Chiari I types 1 and 2 Clinical relevance: -Flaccid paralysis at upper limb (LMN)

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Anterior Spinal Artery Occlusion

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Cause: Ant. spinal artery occlusion Pathology: -Spares nothing except Dorsal Column -All else BILATERAL signs -Spastic paralysis -Loss of pain and temperature -UMN+LMN lesion signs

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Cranial Nerves I~XII

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Midbrain: III, IV Pons: V, VI, VII, VIII Medulla: IX, X, XI, XII "Some Say Marry Money But My Brother Says Big Brain Matters Most" I: Olfactory (S) II: Optic (S) III: Occulomotor (M) IV: Trochlear (M) V: Trigeminal (B) VI: Abducens (M) VII: Facial (B) VIII: Vestibulocochlear (S) IX: Glossopharyngeal (B) X: Vagus (B) XI: Accessory (M) XII: Hypoglossal (M)

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Parinaud Syndrome

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Paralysis of conjugate vertical gaze due to lesion in superior colliculi Common cause: pineal tumor

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Olfactory CN I

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Smell Only cranial nerve without thalamic relay to cortex Sensory nerve

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Optic CN II

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Vision/Sight Only cranial nerve effective by multiple sclerosis Sensory nerve with 2 different destinations: Pretectal Nucleus: Light reflex Lateral Geniculate Nucleus: Vision

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Occulomotor CN III

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Eye movement (except LR, SO) Pupillary constriction (Edinger-Wesphal Nucleus) Accommodation Eyelid opening (levator palpebrae) Motor Neuron Parasympathetic

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Trochlear CN IV

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Eye movement (SO muscle; looking medially and down) Motor neuron

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Trigeminal CN V

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Mastication (Temporalis+Masseter, Medial pterygoid; opening is by lateral pterygoid), facial sensation* (Ophthalmic, Maxillary, Mandibular divisions) Ophthalmic division---> Superior orbital fissure Maxillary division---> Foramen Rotundum Mandibular division--->Foramen Ovale "Standing Room Only" Motor/Sensory neuron

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Abducens CN VI

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Eye movement (LR) Motor neuron

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Facial CN VII

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Facial movement Taste from anterior 2/3 of tongue Lacrimation (tears) Salivation (submandibular+sublingual glands) Eyelid closing (vs. CNIII) Stapedius muscle in ear Motor/Sensory neuron

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Vestibulocochlear CN VIII

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Hearing, balance

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Glossopharyngeal CN IX

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Taste from posterior 1/3 of tongue Swallowing Salivation (parotid gland) Monitoring carotid body and sinus chemo-/baroreceptors Stylopharyngeus (elevates pharynx+larynx)

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Vagus CN X

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Taste from epiglottic region Swallowing Palate elevation Midline uvula Talking Coughing Thoracoabdominal viscera Monitoring aortic arch chemo-/baroreceptors

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Facial Lesions UMN

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Lesion: lesions of motor cortex or connection between cortex and facial nucleus Signs: Contralateral paralysis of lower face ONLY; upper face receives bilateral UMN innervation

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Facial Lesions LMN

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Lesion: lesions of neurons after facial nucleus to innervate the face Signs: Ipsilateral paralysis of UPPER+LOWER face

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Bell's Palsy

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"ALexander graHam BELL with STD" A: AIDS L: Lyme disease H: Herpes simplex BELL: Bell's Palsy S: Sarcoidosis T:Tumors D:Diabetes Cause: Complete destruction of the facial nucleus itself or its branchial efferent fibers (CNVII) Signs: Peripheral ipsilateral facial paralysis with inability to close eye on involved side

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Weber Test + Rinne Test

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Auditory tests Weber Test: -Place tuning fork at the middle of skull -Normally hearing should be equal bilaterally -If sensorineuro deficit in l/r ear will result in decreased sound in effected ear -If conductive deficit in l/r ear will result in decreased sound in normal ear Rinne Test: -Place tuning fork behind ear on the mastoid process; once sound fades place tuning fork next to ear (air conduction>bone conduction) and normally the sound should reappear -If conductive deficit in the ear the sound will not reappear once tuning fork placed next to ear

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Marcus Gunn Pupil

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Afferent pupillary defect (e.g., due to optic nerve damage or retinal detachment; bilateral pupillary reflex ⬇)

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Adie Pupil

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Dilated pupil that reacts sluggishly to light, but better to accommodation Cause: Ciliary ganglion lesion

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Argyll Robertson Pupil

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"Prostitute's Pupils" Accommodation to light but no reflex; lesion in the pretectal nucleus

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MLF Syndrome

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Cause: Lesion in the medial longitudinal fasciculus (MLF) Signs: -Medial rectus palsy on attempted lateral gaze (look right; the left eye will not move); lesion from contralateral side -Nystagmus in the abducting eye (away from side of lesion; so if continuing previous example it will show a nystagmus to the left since lesion is in the right) -Convergence is normal -Commonly seen in patients with Multiple Sclerosis

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Multiple Sclerosis

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Cause: Autoimmune inflammation and demyelination of CNS Symptoms: -Optic neuritis -MLF syndrome -Hemiparesis -Hemisensory symptoms -Bladder/bowel incontinence Clinical behaviour: -Relapsing and remitting course -Most often affects women in their 20s/30s -Most common in whites -⬆protein (IgG) in CSF -Oligoclonal bands are diagnostic -MRI is gold standard "SIN" S: Scanning speech I: Intention tremor/Incontinence/MLF N: Nystagmus Treatment: -β-interferon or immunosuppressant therapy

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Guillain-Barré Syndrome

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Cause: Inflammation and demyelination of PNS Signs: -Symmetric ascending muscle weakness beginning in distal lower extremities -Facial paralysis in 50% cases -Autonomic functions impaired (cardiac irregularities, hyper/hypotensive) -Almost all patients survive Findings: -CSF protein increase with normal cell count -*albuminocytologic dissociation*

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Medial Medullary Syndrome

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Cause: Anterior spinal artery occlusion Symptoms: -Corticospinal: contralateral UMN lesion (spastic paralysis) -Medial Lemniscus: contralateral loss of sensation, vibrations, touch, and proprioception (dorsal column) -CN XII Hypoglossal: Tongue deviates towards the side of the lesion; flaccid paralysis

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Lateral Medullary Syndrome

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Cause: Posterior Inferior Cerebellar Artery (PICA) occlusion, Wallenberg Syndrome Symptoms: -Spinothalamic tract: Contralateral loss of pain+temperature in the body -Hypothalamic tract: ipsilateral Horner's Syndrome ('PAM') -CN X Vagus (Ambiguus nucleus): Ipsilateral paralysis of larynx/pharynx/palate (dysarthria+dysphagia+loss of gag reflex), the uvula deviates away from lesion side -CN V Trigeminal (Spinal Trigeminal): Ipsilateral pain+temperature loss of face -Vestibular nuclei: vertigo, nausea/vomit, nystagmus -Inf. cerebellar peduncle: ipsilateral limb ataxia

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Medial Pontine Lesion

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Cause: Paramedian branches of basilar artery Symptoms: -Corticalspinal: contra. UMN lesions -Medial lemniscus: contra. loss of touch/vibrations/proprioception/sensation -CN VI Abducens: lateral rectus muscle inhibited; medial strabismus

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Lateral Pontine Lesion

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Cause: AICA Symptoms: -Spinothalamic tract: loss of contra. pain/temp of body -Hypothalamic tract: ipsilateral Horner's ('PAM') -Vestibular nuclei: vertigo, nausea/vomit, nystagmas -CN V Trigeminal nucleus: ipsilateral loss of pain/temp of face -CN VII Facial nucleus: ipsilateral facial paralysis -CN VIII Cochlear nucleus: ipsilateral loss of hearing

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Pontocerebellar Angle Syndrome

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Cause: acoustic neuroma/Schwannoma of CN VIII Symptoms: -slow-growing tumor from Schwann cells in vestibular nerve -Growth of timor can exert pressure on CNVII+V -Signs of brain stem lesion without long tract signs -VIII: vertigo, nausea/vomit, nystagmus -VII: Facial paralysis -V: Pain/temp sensation loss of face

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Medial Midbrain Syndrome (Weber Syndrome)

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Symptoms: -Corticospinal Tracts: contralateral UMN lesion signs -CN III Occulomotor: ipsilateral strabismus -Corticobulbar tracts: contralateral lower face spastic paralysis (UMN)

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Benedikt Syndrome

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CN III Occulomotor roots Complete ipsilateral occulomotor paralysis -Ptosis -Fixation and dilation of ipsilateral pupil

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Trigeminal Nerve CN V Nucleus

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1. Principal Nucleus: Discriminative sensation, light touch of face, conscious proprioception of the jaw 2. Mesencephalic Nucleus: Proprioception of the face 3. Spinal trigeminal nucleus: deep/crude touch, pain/temp, located in the medulla

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Brachial Plexus

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C5-T1 "Randy Travis Drinks Cold Beer" R: Roots (Long thoracic nerve) T: Trunks D: Division C: Cords B: Branches Trunks: Upper (C5, C6), Middle (C7), Lower (C8, T1) Division: Upper+Lower trunks branch to Middle trunk, Middle trunk branches to Upper trunk only Cords: Lateral, Posterior, Medial (All continuations of trunks+divisions) Branches: Musculoskeletal N. (lateral cords), Median N. (lateral+medial cords), Ulnar N. (medial cords), Axillary (posterior cord), Radial (posterior cord)

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Long thoracic nerve

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Trunks: C5-C7 Causes: Stab wound and mastectomy Innervation: serratus anterior Injury symptoms: -Difficult to abduct the arm above 90º -Winged scapula

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Musculocutaneous nerve

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Trunks: C5-C7 Causes: stab wound Innervation: biceps brachii and brachialis muscle Injury: -Difficult to flex arm at elbow -Difficult to supinate forearm -Numbness on lateral forearm

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Axillary nerve

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Trunks: C5-C6 Causes: surgical neck fracture or anterior dislocation of humeral head Injury: -Difficulty to abduct shoulder -Flattened deltoid muscle/atrophy -skin numbness over deltoid muscle

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Radial nerve

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Trunks: C5-C8 "BEST extensors" B: Brachioradialis E: Extensors of wrist and fingers S: Supinators T: Triceps Causes: fracture at mid-shaft of humerus, direct compression at back of axilla ("Saturday night palsy") Injury: -Difficult to pronate forearm -Difficult to extend elbow and wrist (wrist drop*) -Difficult to extend fingers at MP joints -Difficult to extend/abduct thumb (abductor pollicis longus) -Numbness on posterior arm -Numbness on dorsal hand and thumb

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Median nerve

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Trunks: C6-T1 Causes: fracture of supracondyle of humerus, carpal tunnel syndrome or dislocated lunate Injury: -Difficult to opposite or abduct thumb (brevis) -Difficult to flex index and middle fingers -Difficult to flex wrist (ulnar deviation upon flexion) -Numbness in dorsal and velar aspects of lateral 3.5 fingers and greater thenar eminence Median CLAW of 2nd+3rd digits Ape Hand (opponens pollicis muscle function lost; inability to abduct thumb)

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Carpal Bones

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Scared Lovers Try Positions That They Can't Handle (From proximal row starting laterally) S: Scaphoid L: Lunate T: Triquetrium P: Pisiform T: Trapezium T: Trapezoid C: Capitate H: Hamate

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Ulnar nerve

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Trunks: C8-T1 Causes: fracture of medial epicondyle of humerus, fracture at hook of hamate (falling on outstretched hand) Motor function: -medial finger flexion -wrist flexion (radial deviation upon flexion) -abduction and adduction of fingers -adduction of thumb Injury: -Difficult to abduct and adduct 2nd~5th fingers -Difficult to adduct thumb (adductor pollicis) -Claw Hand ("Pope's blessing")

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Erb-Duchenne Palsy

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Common cause: violent stretch between head & shoulder leads to upper trunk injury (C5, C6) Affected nerves: -Musculocutaneous nerve: biceps brachii+brachialis -Axillary nerve: teres minor, deltoid -Suprascapular nerve: supraspinatus, infraspinatus Symptoms: -Waiter's tip: pronated and medially rotated arm, with an ipsilateral paralysis of diaphragm

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Klumpke Palsy

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Common Cause: Sudden upward pull of arm, lower trunk injury (C8-T1) Symptoms and signs: -Atrophy of thenar/hypothenar eminences -Atrophy of interosseous muscles -Sesnroy deficits of medial side of forearm and hand -Horner's syndrome Affected nerves: -Median nerve: function loss of wrist and hand -Ulnar nerve -Sympathetic nerve finer from T1 "total claw hand"

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Blood-Brain-Barrier composition?

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"Hey who got in? TBA..." T: Tight Junctions B: Basement membrane A: Astrocytes

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Essential Tremor

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Postural Tremor Tremor occurs when holding a posture; autosomal dominant Patients often self medicate using alcohol which will decrease the tremor Treatment: β-Blockers

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Resting tremor

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Most noticeably distally Seen in Parkinson's Disease (Pill-rolling tremor)

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Intentional tremor

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Tremor occurs when pointing toward a target Associated with cerebellar dysfunction

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Myoclonus

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Sudden, brief muscle contraction (Jerks; hiccups)

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Dystonia

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Sustained, involuntary muscle contractions (Writer's cramp)

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Athetosis

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Slow, writhing movements, especially of fingers Characteristic of basal ganglia lesion (Huntington's)

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Chorea

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Sudden, jerky, purposeless movements Characteristic of basal ganglia lesion (Huntington's)

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Internal Carotid Aneurysm

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Example: Left side aneurysm 1) Medial expanding aneurysm: more likely to compress the temporal optic nerve axons resulting in left nasal hemiopsia 2) Later expanding aneurysm: more likely to compress the various sinus; abducens nerve; resulting in medial strabismus

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Anterior cerebral artery

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Supply: Medial aspect of motor/sensory cortex; legs+foot area Aneurysm: result in contralateral lower extremities numbness

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Anterior communicating artery

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Most common site of circle of Willis aneurysm Lesions may cause visual field defects Berry aneurysms most commonly occur at this artery Rupture leads to hemorrhagic stroke/subarachnoid hemorrhage

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Posterior communicating artery

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Common area of aneurysm Lesions will cause CNIII Palsy

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Watershed zones

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Damage results from severe hypotension anterior cerebral/middle cerebral posterior cerebral/middle cerebral Upper extremities weakness + higher-order visual processing

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Berry Aneurysm

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Commonly occur at anterior communicating artery Rupture is the most common complication -hemorrhagic stroke -subarachnoid hemorrhage Associated with: -adult polycystic kidney disease -Marfan's syndrome -Ehlerys-Danlos syndrome

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Charcot-Bouchard microaneurysms

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Associated with chronic hypertension Affects small vessels (basal ganglia)

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Epidural Hematoma

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Bleeding between skull/periosteal dura Rupture of middle meningeal artery (often 2º to fracture of temporal bone) Lucid interval (talk & die syndrome) Rapid expansion under systemic arterial pressure CNIII Palsy CT shows "biconvex disk" not crossing suture lines

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Subdural Hematoma

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Bleeding between meningeal dura/Arachnoid Rupture of bridging veins. Slow venous bleeding (less pressure = bleeding develops over time) with delayed onset of symptoms Seen in elderly individuals, alcoholics, blunt trauma, shaken baby (whiplash, brain atrophy, shaking) Crescent-shaped hemorrhage that crosses suture lines; gyro are preserved

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Subarachnoid hemorrhage

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Bleeding inside the subarachnoid space Rupture of an aneurysm (usually berry aneurysm in Marfan's, Ehler-Danlos, APCKD) or an AVM (atriovenous malformations) Patients complain of 'worst headache of my life" Bloody or yellow (xanthochromic) spinal tap

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Ventricular System Flow

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Lateral ventricle-->foramen of Monro-->3rd Ventricle-->cerebral aqueduct-->4th ventricle-->foramen Luschka/Magendie-->venous sinus

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Normal pressure hydrocephalus

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"wet, wobbly, and wacky" Does NOT result in increase of subarachnoid space volume; ventricles expand and distorts the radiation fibers causing the clinical triad: Dementia Ataxia (magnetic gait) Urinary incontinence

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Communicating hydrocephalus

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CSF absorption decreased by arachnoid villi Increase in intracranial pressure papilledema herniation

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Obstructive hydrocephalus

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Caused by structural blockage of CSF circulation within the ventricular system (herniations, etc.)

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Hydrocephalus ex vacuo

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Appearance of increase in CSF due to brain atrophy; no triad observed and intracranial pressure is normal Seen in Alzheimer's disease, HIV, Pick's disease

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Spinal tap needle insertion level

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L3~L5 Spinal cord extends to lower border of L1~L2 while subarachnoid space extends to lower border of S2.

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Vagal Nuclei

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Nucleus Solitarius: Visceral Sensory information (taste, baroreceptors, gut distentions)...CNVII, IX, X Nucleus aMbiguus: Motor innervation of pharynx, larynx, and upper esophagus (swallowing, palate elevation)...CN IX, X, XI Dorsal motor nucleus: sends autonomic (parasympathetic) fibers to heart, lungs, and upper GI

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Cranial Nerve Pathway: Optic Canal

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CN II, Ophthalmic artery, central retinal vein

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Cranial nerve pathway: Superior orbital fissure

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CNIII, IV, V1, VI opthalmic vein sympathetic fibers

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Cranial nerve pathway: Foramen Rotundum

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CN V2

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Cranial nerve pathway: Foramen Ovale

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CN V3

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Cranial nerve pathway: Foramen spinosum

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Middle meningeal artery/vein *Foramen spinosum is located in the floor of the middle cranial fossa*

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Cranial nerve pathway: Cavernous sinus

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CN III, IV, V1, V2, VI

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Glaucoma

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Open/Wide angle: obstructed outflow (canal of Schlemm); silent, more common, painless closed/narrow angle: obstruction of flow between iris and lens; pressure buildup behind iris; very painful, decreased vision, rock-hard eye, frontal headache; ophthalmic emergency; do NOT give epinephrine

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Cataract

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Bilateral painless opacification of lens; decrease in vision Risk factors: age, smoking, etOH, sunlight, classic galactosemia, galactokinase deficiency, diabetes (sorbitol), trauma, infection

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Papilledema

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Increase in intracranial pressure causing elevated optic disk with blurred margins; bigger blind spy (seen in hydrocephalus)

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Obturator Nerve (L2-L4)

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Anterior hip dislocation Thigh adduction deficit Medial thigh sensory deficit

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Femoral Nerve (L2-L4)

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Pelvic fracture Thigh flexion and leg extension deficit Anterior thigh + medial leg sensory Loss of knee jerk reflex

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Common peroneal nerve (L4-S2)

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Trauma to lateral aspect of leg or fibula neck fracture Foot eversion and dorsiflexion; toe extension; *foot drop, *foot slap, stoppage gait Anterolateral leg and dorsal aspect of foot "PED" Peroneal Everts and Dorsiflexes; if injured, foot dropPED Branch of sciatic nerve

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Tibial nerve (L4-S2)

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Knee trauma Foot inversion and plantar flexion; toe flexion Sole of foot sensory "TIP" Tibial Inverts and Plantarflexes; if injured, can't stand on TIPtoes Branch of sciatic nerve

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Superior gluteal (L4-S1)

answer

Posterior hip dislocation or polio Thigh abduction (positive Trendelendburg sign - hip drops when standing on opposite foot) stabilize pelvis

question

Inferior gluteal (L5-S2)

answer

Posterior hip dislocation Can't jump, climb stairs, or rise from seated position; can't push downward "Can't jump, can't stand, can't climb a tree" extension of hip; lateral rotation of thigh

question

Amnesia

answer

-FA p443 says Korsakoff is classic anterograde amnesia, but it may also casue retrograde amnesia. So, its amnesia is nonspecific, depending on which brain structure is damaged. We know that Korsakoff is not gonna happen in a short time, brain lesions happen in the order of thiamine def --> wernike ( still reversible ) --> Korsakoff ( irreversible ). Confabulations requires at least 10 years of alcoholism. ( Kaplan 's psychiatry book ). There are not just the mamillary bodies that are hit on but they are the first to be affected. So, Korsakoff's=irreversible,damaged mamilary bodies, nonspecific amnesia, mostly anterograde but retrograde also possible. - The hippocampus is in the temporal lobe, consolidating short term memory into long term memory, so damage of the "seahorse" will cause the loss of anterograde memory only. Anterograde amnesia due to hippocampus lesion is probably the consequence of (1)head trauma->temporal lobe lesion (2)hypoxia->neuron death (3)HSV-1 infection of temporal lobe (4)epilepsy. Alcoholism is not specific for temporal lobe damage.

question

Types of memory

answer

There are 3 types of memory, short term, medium term and long term. Short term memory (things that can be recalled within minutes or some hours are stored in the hippocampus) Medium term memory (things that can be recalled within several hours and few days are stored in both the hippocampus and the mamillary bodies)

question

Which artery supplies the medial aspect of motor/sensory cortex?

answer

ACA Anterior cerebral artery

question

What artery supplies the lateral aspect of the motor/sensory cortex?

answer

MCA Middle cerebral artery

question

What muscle does the hypoglossal nerve innervate?

answer

Geniglossus muscle Function: Moves tongue forward and towards opposite side

question

Where does the CN IX lie in the oral cavity?

answer

Tonsillar fossa Innervates stylopharyngeus muscle

question

What nerve is closely associated with anterior scalene muscle?

answer

Phrenic nerve Runs anteriorly to ant. Scalene muscle

question

What is the internal capsule composed of? What does each part innervate?

answer

White matter structure in the brain between the caudate nucleus, the putamen+globus pallidus, and thalamus Shape: >< -anterior limb (frontopontine fibers) -genu (corticobulbar fibers) -posterior limb (corticospinal fibers)

question

What artery supplies the internal capsule?

answer

Lenticulostriate arteries *prone to rupture in uncontrolled hypertension* -contralateral dense hemiplegia of arm+leg -lower facial paralysis (UMN)

question

Where is the CTZ located? Functions?

answer

CTZ= chemoreceptor trigger zone -mediated by vagal afferents -located in the floor of 4th ventricle

question

What are additional findings in patients with Bell's palsy?

answer

-hyperacusis: increased sensitivity to sound b/c of stapedius muscle paralysis -lack of taste sensation in the anterior 2/3 of tongue -disturbed lacrimation and salivation

question

Describe the nervous innervation of the ear

answer

CN VIII: hearing + balance Auriculotemporal nerve: anterior half of the external ear canal Auricular branch of Vagus Nerve: posterior half of the external ear canal Greater Auricular nerve: lower part of auricle Lesser occipital nerve: upper part of auricle

question

Aneurysms at which arteries can compress the oculomotor nerve?

answer

Emerges from the interpeduncular fossa of the midbrain -superior cerebellar artery -posterior cerebral artery (immediately lateral to the basilar artery)

question

Which ganglion can the HSV-1 stay dormant in?

answer

Trigeminal root ganglion Treatment: acyclovir

question

Which muscle protects the underlying structures of the clavicle in an event of a fracture?

answer

Subclavius muscle

question

What structure is immediately medial to the femoral hernia?

answer

Lacunar ligament

question

What cortex receives input from the olfactory bulb?

answer

Piriform cortex

question

What arteries supply the posterior thoracic wall? Anterior thoracic wall? Where do they branch from?

answer

Posterior intercostal arteries -Superior 2 pairs arise from costocervical trunk (Note: costocervical trunk arise behind scalenus muscle on right side, medial to scalenus muscle on left side) -Inferior 9 pairs arise from thoracic aorta Anterior intercostal arteries -Internal thoracic artery (Note: arises from subclavian artery superiorly, descends just lateral to the sternum) Note: Chest tube insertion Midaxillary line + 5th intercostal space ABOVE THE RIB (only collateral branches of intercostal blood supply + innervation are relevant)

question

Pancoast Tumor

answer

Tumor of the lung that is at the apex and invades into the cervical plexus/sympathetic ganglion nervous system which can result in Horner's syndrome

question

What is the muscle responsible for holding the food inside your mouth? Innervation?

answer

Buccinator Innervated by facial nerve CN VII

question

Which artery defects can cause vision deficits? What types? (Name all)

answer

Anterior communicating artery: Bitemporal hemianopia (along with prolactinoma, compression of CNIII at optic chiasm, etc) Internal carotid artery: Binasal hemianopia Ophthalmic artery: monocular blindness Posterior cerebral artery: homonymous hemianopia with macular sparing* (due to dual blood supply of macula) Posterior communicating artery: CN III palsy

question

What vision defect can be caused by anterior communicating artery lesion?

answer

Bitemporal hemianopia

question

Lesion in which artery can cause bitemporal hemianopia?

answer

Anterior communicating artery

question

What vision defect can result from a lesion in the internal carotid artery?

answer

Binasal hemianopia

question

Lesion in which artery can cause binasal hemianopia?

answer

Internal carotid artery

question

What vision defect can result from ophthalmic artery?

answer

monocular blindness

question

Lesion to which artery can cause monocular blindness?

answer

Ophthalmic artery

question

What are some causes of bitemporal hemianopia?

answer

1. Prolactinoma 2. Craniopharyngioma 3. Anterior communicating artery lesion 4. Tumor (pressure against CNIII at optic chiasm)

question

What vision defect can be seen from a lesion in the posterior communicating artery?

answer

CN III palsy

question

Lesion to which artery can cause CNIII palsy

answer

Posterior communicating artery

question

What visual defects can be seen from a lesion in the posterior cerebral artery?

answer

Homonymous contralateral hemianopia with macular sparing due to dual blood supply of macula

question

Lesion to which artery can cause homonymous hemianopia with macular sparing?

answer

Posterior cerebral artery

question

What are the causes and symptoms of sciatica?

answer

Sciatic nerve: -arise from lumbosacral plexus -composed of fibular + tibial nerve Causes: (not complete) -pregnancy -spinal stenosis -disc herniation -compression of nerve Clinical symptoms may include: -loss of flexion at the knee -loss of function below the knee (PED + TIP) -weakened extension of the thigh

question

Which nerve is directly adjacent to the flexor digitorum superficialis?

answer

Median nerve

question

Aneurysm of the axillary artery at the axilla can result in what neural defect?

answer

Axillary artery at the axilla is wrapped in a sheath with 3 cords of the brachial plexus Aneurysm at this site can cause compression in any of the 3 cords Cords of the brachial plexus are located at the axilla; the divisions and trunks are higher up by the clavicle and cervix

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