Clinical Neuroanatomy Flashcards
What does the dura mater consist of?
Periosteal layer (stuck to skull) and meningeal layer-they come together and can form sinuses/cavities
Falx cerebri
Made of meningeal layer of dura and separates the 2 hemispheres
Tentorium cerebelli
Separates the cerebrum from the cerebellum (everything above is anterior fossa)
-Supratentorium is where most brain in adults are
Presentation of epidural hematoma
Pt with lucid interval and then rapid deterioration (due to a fast arterial bleed and compression of brainstem)
What vessel is injured in epidural hematoma?
Middle meningeal artery
What does epidural hematoma look like on CT?
Lenticular (like lens)
Common presentation of subdural hematoma
Older pt with insidious onset of HA, confusion, problems with speech and drowsiness
(as brain tissue atrophies and pulls away from periosteum, the veins are more vulnerable to shearing injuries)
What vessel is injured in subdural hematoma?
Bridging veins
What does subdural hematoma look like on CT?
Crescent shape
Presentation of subarachnoid hemorrhage
“Worst HA of my life”-might have had bowel movement of something of that sort (rapid deterioration)
Cause of subarachnoid hemorrhage
Aneurysm
How does subarachnoid hemorrhage look on CT
Spiderlike
What might be some changes to ventricles seen on CT?
Effacement of ventricles due to mass effect (smushed)
Enlarged temporal horns if blood in them etc
What does wet, wacky and wobbly describe?
Urinary continence, confusion and magnetic gait (can’t lift foot) seen with normal pressure hydrocephalus (overproduction of CSF)
Blood to brain
Right common carotid (off brachiocephalic)
Left common carotid (off aorta)
Vertebral arteries (off subclavian)
Basilar artery (from vertebral arteries joining)
What blood vessel is supplying most of the lateral brain?
Middle cerebral artery
What blood vessel is supplying the center of the brain nearest the longitudinal fissure?
Anterior cerebral artery
What’s inside the cavernous sinus?
All nerves controlling EOMs (CN III, IV, VI)
All divisions of CN 5 (except V3)
Internal carotid artery
What is the presentation of a pt with compression of cavernous sinus (like with cavernous fistula)?
Opthalmoplegia (eye pain, double vision, EOM paralysis, chemosis) and decreased facial sensation
-May have weird eye bulge (proptosis) due to increased ICP
Order of CNS
Cortex (UMN) Subcortical Brainstem Cerebellum Spinal cord
Order of peripheral nervous system
Lower motor neuron
Peripheral nerve
NMJ
Muscle
Where is vision located?
Occipital lobe
Where is memory, understanding, language located?
Temporal lobe
Where do you look with a lesion?
“at the lesion” (b/c the opposite side is firing more)
What cranial nerves are from the midbrain?
II, III, IV
What cranial nerves are from the pons?
V, VI, VII
What cranial nerves are from the medulla
IX, X, XI, XII
Where does CN VIII come from?
Pons and medulla
What is pyramidal decussation?
UMN (corticospinal tract) starts in the cortex and in the lower medulla, it crosses over and goes to the opposite side of the body in the lateral corticospinal tract (why opposite side of the cortex controls contralateral innervation)
What is the internal capsule?
Sub cortical area (shaped like X) where the nerves for all of leg, trunk, arm and face all go through– would have to have a huge lesion in the cortex to affect all but only a tiny stroke here to paralyze them all
What are crossed signs?
Ipsilateral cranial nerve deficits and contralateral body weakness (b/c CNs don’t have contralateral innervation)
-ex: R CN 7 affect the R side of the face but cortex lesion at face of Humunculus on R will affect the L side
Where are the vibration and proprioception senses?
Posterior column
Where is voluntary movement?
Lateral corticospinal area
Where are pain and temperature senses?
Lateral spinothalamic area
+ Romberg
Proprioception is off so problem in dorsal column (posterior) and think B12 deficiency
Where do the sensations of vibration and proprioception cross?
At the level of the brainstem
Where do the sensations of pain and temperature cross?
At the level of the spinal cord (and then goes to the parietal cortex)
What is Brown Sequard syndrome?
Loss of pain, temp and light tough on opposite side of lesion
Loss of motor function and vibration, position and deep touch sensation on same side as cord damage
Central cord syndrome presentation
Bilateral loss of pain and temperature (b/c corssing in the spinal cord)
Anterior cord syndrome presentation
Paralysis and loss of pain and temp (lateral)
Posterior cord syndrome presentation
Loss of vibration and proprioception (B12)
Posterior and lateral column cord syndrome presentation
Paralysis (lose voluntary movement) and loss of vibration and proprioception
Presentation of cauda equina syndrome
More severe pain and weakness Asymmetric Severe radicular pain Flaccid LE paralysis Saddle anesthesia Late and less severe bowel and bladder problems
Presentation of conus medullaris syndrome
Less severe pain and weakness Symmetric Bilateral and perianal pain Mild to mod LE weakness Saddle anesthesia Early, severe bowel and bladder problems
What must be remembered about cauda equina and conus medullaris syndrome?
They are both emergencies and require immediate neuroimaging and decompression
What is the nerve root?
Comes off the spinal cord and has sensation and motor in it
LMN vs peripheral nerve lesion
LMN is weakness
Peripheral nerve is weakness and numbness
The first 3 questions with a neuro problem
Is it neurologic?
Where is the lesion?
What is the pathological process?
Presentation of lesion in the cortex
Aphasia, neglect, hemianopia
(UMN hemiparesis, hemisensory involving face and arm vs legs)
*face and arm not affected same as leg so NOT equal
Presentation of lesion in the subcortical structures (internal capsule and basal ganglia)
Dense hemiplegia (face, arm, leg etc) Abnormal movements (chorea, ballism, tremor, cogwheeling)
Presentation of lesion in the cerebellum
Truncal vs limb ataxia and dysmetria
Presentation of lesion in the brainstem
CN palsies and crossed signs
Presentation of lesion in the spinal cord
Paraparesis, sensory level different below lesion, Bowel/Bladder involvement (rectal tone), saddle anesthesia
*bilateral LE weakness and paralysis!!
Presentation of lesion in the LMN
No sensory involvement, fasciculations (muscles contract on own and see little worms under skin)
Presentation of lesion in the peripheral nerve
Distal weakness and sensory involvement, usually stocking glove, areflexia or hypoflexia
Presentation of lesion in the NMJ
Fatigability, no sensory involvement, normal DTRs
Presentation of lesion in the muscle
Proximal weakness, symmetric, no sensory involvement
How to determine the underlying pathology
Vascular Inflammatory Trauma Autoimmune Metabolic Infectious Neoplastic Congenital Drugs Epilepsy/seizures
Optic nerve
Visual acuity, color vision (red desaturation-optic neuritis with MS), visual fields
Do fundoscopic exam and check pupils
What is involved in normal response to light when shine in left eye?
L CNII intact and R and L CN III intact
Cranial nerve 5
Sensation of face, muscles of mastication, sensory limb of corneal reflex
Cranial nerve 7
Muscles of facial expression
Motor limb of corneal reflex
CN 3 lesion
Lack of eyelid opening or ptosis
CN 7 lesion
Lack of eyelid closure
Gag reflex
CN9 to 10
Vestibulo-ocular reflex
CN 8 to 6 and 3 (abnormal is if head rotated to right and eyes move and follow-brainstem damage)
CN 12 lesion
In brainstem then lick your lesion when stick out tongue
Reasons for spasticity
Velocity dependent
UMN lesion
Reasons for rigidity
Velocity independent
Cogwheel rigidity
Basal ganglia lesion
Clues to UMN
Spastic weakness
Hyperreflexia
Babinski
Clues to LMN
Flaccid weakness
Hyporeflexia
Atrophy
Fasciculations
If face and arm is > leg?
MCA
If leg is greater than arm/face?
ACA
