Neuro - Anatomy & Physiology Part 2 Flashcards
A patient presents after falling from a window on the fourth floor of a building. Computed tomography shows a biconvex disk that do not cross suture lines. What type of intracranial hemorrhage does this patient have?
Epidural hemorrhage
What type of cerebral hematoma is associated with diabetes mellitus, amyloid angiopathy, and tumor?
Parenchymal hematoma
Calcium channel blockers are used to prevent which sequela of subarachnoid hemorrhage?
Vasospasm
A xanthochromic spinal tap is evidence of what?
Subarachnoid hemorrhage
On computed tomography, what type of intracranial hematoma appears as a crescent-shaped hemorrhage that crosses suture lines?
Subdural hematoma
Where in the brain do parenchymal hematomas commonly occur?
Basal ganglia and internal capsule
Stroke appears _____ (bright/dark) on diffusion-weighted magnetic resonance imaging scan 3-30 minutes after occurrence and _____ (bright/dark) on computed tomography after 24 hours.
Stroke is bright on diffusion-weighted magnetic resonance imaging and dark on computed tomography
What are lacunar strokes?
Strokes that involve small vessels and are due to hypertension
What are two common causes of hemorrhagic stroke?
Aneurysm rupture or reperfusion of an ischemic stroke
What is the treatment for ischemic stroke?
Tissue plasminogen activator (must be administered within 3 hours)
Name four conditions that result in increased risk of ischemic stroke.
Atrial fibrillation, carotid dissection, patent foramen ovale, and endocarditis
What is a TIA?
Transient ischemic attack, a brief, reversible episode of neurologic dysfunction due to focal ischemia
Which dural venous sinuses meet at the confluence of the sinuses?
Superior sagittal sinus, straight sinus, occipital sinus
All cranial venous sinuses ultimately drain into the vein that courses through the jugular foramen, which is called what?
The internal jugular vein
What is the main location of cerebrospinal fluid return to the venous circulation via arachnoid granulations?
The superior sagittal sinus
The lateral ventricles communicate with the third ventricle via what structures?
The foramina of Monro (interventricular foramina)
The third ventricle communicates with the fourth ventricle via what structure?
The aqueduct of Sylvius (the cerebral aqueduct)
The fourth ventricle communicates with the subarachnoid space via what structures laterally and medially?
The foramina of Luschka laterally and the foramen of Magendie medially
Cerebrospinal fluid is produced by _____ _____ (tissue) and reabsorbed by _____ _____ (structure).
Choroid plexus; arachnoid granulations
What condition can be caused by impaired flow or reabsorption of cerebrospinal fluid?
Hydrocephalus
What are the four types of hydrocephalus?
Normal pressure, communicating, obstructive (noncommunicating), hydrocephalus ex vacuo
What is the classic triad of symptoms in normal-pressure hydrocephalus?
Dementia, gait problems, and urinary incontinence in an elderly patient
What is the cause of communicating hydrocephalus?
Impaired absorption of cerebrospinal fluid by arachnoid granulations
In normal pressure hydrocephalus, ventricles are _____ (enlarged/normal size/small) and opening pressure is ______ (low/normal/high).
Enlarged; normal
What is the cause of obstructive hydrocephalus?
Structural blockage of cerebrospinal fluid circulation within the ventricular system
What type of hydrocephalus is caused by stenosis of the aqueduct of Sylvius (cerebral aqueduct)?
Obstructive hydrocephalus
What is hydrocephalus ex vacuo? How does it affect intracranial pressure?
Appearance of increased cerebrospinal fluid secondary to brain atrophy; intracranial pressure is normal
What is the most common location for a vertebral disk herniation (between which two spinous processes)?
Between L5 and S1
How many cervical, thoracic, lumbar, sacral, and coccygeal spinal nerves are there (each and total)?
Eight cervical, 12 thoracic, five lumbar, five sacral, one coccygeal; total = 31
Which nerves exit intervertebral foramina above the corresponding vertebrae?
C1-C7
Which nerves exit intervertebral foramina below the correspondingly named vertebrae?
C8 and below
Where is the lower border of the spinal cord in adults?
Between L1 and L2
When doing a spinal tap, it is important to keep the spinal needle between which two spinous processes to avoid hitting the cord?
L3 and L5; the needle should pass through the L3-L4 or the L4-L5 interspaces
During a lumbar puncture, cerebrospinal fluid is obtained from which fluid space in the spine?
The subarachnoid space
When performing a lumbar puncture, what bony landmarks may be used to indicate the levels of L4 and L5?
The iliac crests
Name the three ligaments that are pierced during a lumbar puncture.
Supraspinous, interspinous, and ligamentum flavum
Once a needle enters the epidural space, what other structures must be passed through to enter the subarachnoid space?
The dura mater, the subdural space, and the arachnoid
Which spinal column conveys pressure, vibration, touch, and proprioception information to the brain: dorsal, lateral corticospinal, or spinothalamic?
Dorsal
What part of the dorsal column transmits sensory information from the upper body and the upper extremities?
The fasciculus cuneatus
What part of the dorsal column transmits sensory information from the lower body and lower extremities?
The fasciculus gracilis
What nervous system tract in the spinal cord is responsible for ascending pain and temperature sense?
The spinothalamic tract
Which spinal column is a nerve tract that conveys voluntary motor impulses from the brain to the muscles: dorsal, lateral corticospinal, or spinothalamic?
The lateral corticospinal tract
Which arteries perfuse the dorsal columns?
Posterior spinal arteries
Innervation of the legs is _____ (lateral/medial) to that of the arms in the dosal columns.
Medial
Innervation of the legs is _____ (lateral/medial) to that of the arms in the lateral corticospinal tract.
Lateral; remember: Legs are Lateral
Innervation of the legs is _____ (lateral/medial) to that of the arms in the spinothalamic tract.
Lateral; remember: Legs are Lateral
Which tract carries sensory information from the nucleus cuneatus (or gracilis) of the medulla to the ventral posterior lateral nucleus of the thalamus?
Medial lemniscus
The dorsal column/medial lemniscal pathway synapses in which two nuclei before reaching the sensory cortex?
The ipsilateral nucleus cuneatus (or gracilis) and the ventral posterior lateral nucleus of the thalamus
The spinothalamic tract synapses in what area of the thalamus before reaching the sensory cortex?
The ventral posterior lateral nucleus of the thalamus
The first synapse of the spinothalamic tract occurs in the _____ (ipsilateral/contralateral) gray matter, and the axons ascend on the _____ (ipsilateral/contralateral) side of the cord.
Ipsilateral; contralateral
Which spinal tract conveys voluntary movement stimuli to the contralateral limbs from the brain?
The lateral corticospinal tract
Trace the path of an upper motor neuron from the cortex to the spinal cord.
The axon descends ipsilaterally through the internal capsule until it decussates at the caudal medulla (pyramidal decussation), and then descends contralaterally
Where does the second synapse of the lateral corticospinal tract occur?
The neuromuscular junction
Where do upper motor neurons synapse with lower motor neurons?
Anterior horn of the spinal cord
Where do the third-order neurons of the spinothalamic tract and the dorsal column/medial lemniscal pathway originate and terminate?
They originate in the ventral posterior lateral of the thalamus and terminate in the sensory cortex
Ascending pressure, vibration, touch, and proprioceptive sensation are carried by which pathway within the spinal cord?
The dorsal column/medial lemniscal pathway
Trace the pathway of a first-order neuron of the dorsal column/medial lemniscal pathway from sensory receptor to the first synapse.
A first-order neuron of the dorsal column/medial lemniscal pathway proceeds from the sensory nerve ending to the dorsal root ganglion, enters the spinal cord, and ascends ipsilaterally in the dorsal column
A-delta and C fibers synapse on neurons found in which spinal tract?
The spinothalamic tract
The _____ (first/second)-order neuron of the spinothalamic tract decussates at the _____.
Second; anterior white commissure
Which structure contains cell bodies of the first-order neurons of the spinothalamic and dorsal column tracts?
Dorsal root ganglion
A patient presents with weakness, Babinski;s reflex, and increased reflexes and tone in the legs. Is he more likely to have an upper or lower motor neuron lesion?
Upper motor neuron lesion
What symptoms would you expect from someone with an upper motor neuron lesion?
Weakness, Babinski;s reflex, spastic paralysis, clasp knife spasticity, and increased reflexes and tone (remember: Upper MN = tone/toes/DTRs go up)
What symptoms would you expect from someone with a lower motor neuron lesion?
Weakness, atrophy, fasciculation, and decreased reflexes and tone (remember: Lower MN = lowertone/toes/reflexes/muscle mass)
When is an upgoing toe reflex (Babinski;s reflex) considered normal?
In infants
Weakness, atrophy, fasciculations, and decreased reflexes and tone are indicative of what type of lesion, upper or lower motor neuron?
Lower motor neuron lesion
Do poliomyelitis and Werdnig-Hoffman disease (SMA I) present with upper motor neuron, lower motor neuron signs, or both? What is the principle resulting symptom?
Lower motor neuron signs only, due to destruction of the anterior horn; flaccid paralysis
What kind of spinal cord lesions are found in multiple sclerosis?
Random and asymmetric lesions due to autoimmune demyelination
What signs and symptoms are associated with multiple sclerosis?
Scanning speech, intention tremor, and nystagmus; as well as multiple sensory and motor symptoms separated in both time and location
What types of neurologic signs are found in amyotrophic lateral sclerosis?
Combined upper and lower motor neuron deficits but no sensory deficit
A complete occlusion of the anterior spinal artery would spare which two areas of the spinal cord?
Dorsal columns and tract of Lissauer, which are perfused by the posterior spinal arteries
What kind of a spinal cord lesion or deficit is found in tabes dorsalis? What infectious agent generally causes it?
Degeneration of the dorsal roots and dorsal columns; caused by tertiary syphilis
What signs and symptoms are associated with tabes dorsalis due to tertiary syphilis?
Impaired proprioception and locomotor ataxia
What kind of spinal cord damage is found in syringomyelia? What signs and symptoms result?
Damage to the anterior white commissure of the spinothalamic tract; loss of pain and temperature sensation bilaterally at the level of the lesion
What three areas of spinal cord are damaged in vitamin B12neuropathy and Friedreich;s ataxia?
Demyelination of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts
What four signs are associated with vitamin B12neuropathy and Friedreich;s ataxia?
Ataxic gait, hyperreflexia, and impaired position and vibration sense
Multiple sclerosis mostly affects _____ (white/gray) matter in the _____ (cervical/thoracic/lumbar) region of the spinal cord.
White; cervical
By what route is polio transmitted?
Fecal-oral
Polio replicates in what two structures before spreading through the bloodstream to the central nervous system?
The oropharynx and the small intestine
What abnormalities of the cell count would be expected in the cerebrospinal fluid of a patient with poliomyelitis?
Lymphocytic pleocytosis