Flashcards in CNS Anatomy Deck (51):
What cranial nerves and other structures run through the cavernous sinus?
Oculomotor, Trochlear, Ophthalmic (V1), Maxillary (V2), Abducens, internal carotid artery
What are the most common pineal-region tumors?
Frontal eye fields are cortical areas that generate saccades in the _____ direction.
What is the medial longitudinal fasciculus?
It links the 3rd cranial nerve on one side with the 6th cranial nerve on the other side, ensuring simultaneous activation of the medial and lateral rectus muscles to preserve conjugate gaze.
What is treatment for optic neuritis (blurry vision and eye pain on movement)?
IV steroids followed by oral taper.
What is the afferent pupillary defect?
In patients with an APD, the direct pupil response is impaired. As such, the affected eye will paradoxically dilate when a flashlight is swung from the unaffected eye to the affected eye. When the flashlight is held in front of the unaffected eye, both pupils will constrict due to preservation of the consensual pupil response. When the eyes are simply observed together in ambient light, each eye perceives the same average amount of light and the pupils will therefore be the same size.
MS symptoms can be temporarily worsened by what?
Heat, hot baths. Called Uhthoff's phenomena.
Which vitamin deficiency has been linked to an increased risk of developing MS?
Vitamin D - less common near equator
What is L'Hermitte's sign?
Electrical shock sensations in the limbs and body brought on by movement of the neck, due to pathology of cervical spinal cord.
What is Fingolimod (Gilyena) and how does it work?
First oral MS drug - blocks T-cell egress from lymph nodes. Can cause first dose bradycardia.
Scale to measure MS disability?
Expanded Disability Status Scale (EDSS).
What is Neuromyelitis optica (Devic's Disease)?
A demyelinating illness characterized by optic neuritis (often bilateral), transverse myelitis, brain MRI non-diagnostic for MS, and NMO-IgG seropositivity (against BBB astrocytes).
Intractable hiccups and nausea/vomiting in NMO patients - where is the lesion?
Electrical shock pain in the posterior tongue and pharynx.
Best initial treatment for trigeminal neuralgia?
Trigeminal neuralgia may be the presenting symptom for what disease?
The trigeminal nerve innervates what?
Muscles of mastication
The trigeminal nerve carries the afferent limb of the _____ reflex, causing what?
Corneal reflex - causes eyes to blink if irritated.
What is the most common form of hearing loss in the elderly?
Presbyacusis - progressive bilateral symmetrical age-related sensorineural hearing loss.
Which muscles act to dampen sounds when talking or chewing?
The Tensory Tympani (Trigeminal nerve) and the Stapedius muscle (seventh nerve).
Conductive hearing loss is due to _____.
Damage of the ossicles.
What is Meniere's disease
Episodes of unilateral hearing loss, tinnitus, sense of fullness in one ear, severe episodes of vertigo.
What are 4 types of meds that are ototoxic?
Aspirin, aminoglycosides (i.e. gentamycin), loop diuretics, chemotherapeutic agents (i.e. cisplatin, carboplatin).
The intermediolateral cell column exists at vertebral levels _____ and mediates the entire sympathetic innervation of the body. Where is the nucleus?
T1 - L2. Nucleus resides in the gray matter of spinal cord.
"Licking the lesion" is characteristic of which CN?
The midbrain contains which cranial nerves?
The pons contains which cranial nerves?
V, VI, VII, VIII
The medulla contains which cranial nerves?
IX, X, XI, XII
Bilateral vestibular schwannomas are often found in which patients?
Which pathway in the spinal cord mediates pain and temperature?
Sensory tracts of the body and spinal cord go to what thalamic structure?
Ventral posterior lateral nucleus (VPL)
Sensory tracts of the cranial nerves of face and head go to what thalamic structure?
Ventral posterior medial nucleus (VPM)
Which pathway contains fibers that transit proprioception and fine touch?
Dorsal column/medial lemniscus pathway
What are upper motor neuron signs?
Increased tone, spasticity, increased reflexes, Babinski.
What are lower motor neuron signs?
Decreased tone, decreased reflexes, atrophy, fasciculations.
Characteristics of Brown-Séquard Syndrom
Weakness ipsilateral to the lesion, loss of proprioception and vibration sensation ipsilateral to lesion, loss of pain and temp sensation to contralateral side of lesion.
Characteristics of central cord syndrome. Can be caused by what?
Loss of pain and tep in a "shawl distribution" due to the spinothalamic tract being affected as it crosses the spinal cord. Can be due to a syrinx/syringomyelia (abnormal fluid collection in the spinal cord).
Characteristics of anterior cord syndrome. When/why does it occur?
Bilateral weakness, bilateral loss of pain/temp, preservation of vibration sensation bilaterally. Occurs due to occlusion of the anterior spinal artery, in patients who become hypotensive, or have surgery on their abdominal aorta.
What is a Chiari malformation?
Congenital disorder defined by downward herniation of the cerebellar tonsils into the foramen magnum and is one of the leading causes of a syrinx. It is generally asymptomatic during childhood, but often manifests with headaches and cerebellar symptoms.
Characteristics of posterior cord syndrome
Loss of proprioception, often patients have intense pain and burning sensations in their limbs.
What is contained in the cauda equina?
10 nerve fiber pairs (5 lumbar, 5 sacral) and a single coccygeal nerve.
What is cauda equina syndrome?
Compression at L4-L5 or L5-S1. Numbness in genitals, buttocks, and anus due to compression of sacral nerve roots, lower extremity weakness, decreased knee reflexes, bowel and bladder retention.
A lesion at L1-L2 is what?
Conus medullaris syndrome: weakness is symmetrical, knee reflexes are preserved, bowel/bladder incontinence and impotence develop early.
The symptoms of amyotrophic lateral sclerosis are caused by degeneration of what?
Motor neurons of the brain, cranial nerve nuclei, and spinal cord (anterior horn cells).
What do EMG studies show in ALS?
fasciculations, fibrillations, and sharp waves.
The only FDA approved medication to slow course of ALS.
Subacute combined degeneration of the spinal cord is caused by what? What does combined mean?
B12 deficiency. Combined refers to damage of the corticospinal tract and dorsal columns.
What substance interferes with B12 metabolism?
Nitrous Oxide (laughing gas)
Cerebellar dysfunction leads to...
Ataxia, hypotonia, intention tremor, wide gait, ocular motor abnormalities, abnormal pauses between words.
Causes of cerebellar dysfunction
Highly affected by toxins (dilantin, EtOH), primary neurodenerative disorders, paraneoplastic degeneration with GYN cancers/anti-YO antibodies.