Neuro - Anatomy & Physiology Part 3 Flashcards
A 6’5” man with long limbs has a CT scan three months after a stroke and “the worst headache of his life.” What caused the stroke?
This man likely has Marfan’s syndrome and developed a berry aneurysm that caused subarachnoid hemorrhage (“worst headache of his life”)
The third division of the trigeminal nerve exits the skull via the foramen _____.
Foramen ovale
The middle meningeal artery exits at the foramen _____.
Foramen spinosum
Which cranial nerves exit the skull through holes in the posterior cranial fossa?
Cranial nerves VII through XII
The internal auditory meatus contains which two cranial nerves?
Cranial nerves VII and VIII
Which foramen contains cranial nerves IX through XI and the jugular vein?
The jugular foramen
Which cranial nerve is found in the hypoglossal canal?
Cranial nerve XII
The spinal cord exits the skull via the _____ _____.
Foramen magnum
The spinal roots of cranial nerve XI and the vertebral arteries exit the skull via which opening?
Foramen magnum
Through which three holes do the three branches of the trigeminal nerve leave the skull? Use the mnemonic Standing Room Only.
V1 through Superior orbital fissure; V2through foramen Rotundum; V3through foramen Ovale
The cavernous sinus is a collection of venous sinuses surrounding which gland?
The pituitary gland
The cavernous sinus contains venous return from which structures? What is the drainage of the cavernous sinus?
Blood from the eye and superficial cortex; the internal jugular vein
Which cranial nerves traverse the cavernous sinus?
Cranial nerves III, IV, V1, V2, and VI
What are the manifestations of cavernous sinus syndrome?
Ophthalmoplegia and ophthalmic and mandibular sensory loss
Which artery passes through the cavernous sinus?
Internal carotid artery
A lesion of CN XII results in tongue deviation _____ (toward/away from) the side of the lesion.
Toward (remember: lick your wounds)
A patient;s jaw deviates to the right; this indicates a lesion in which cranial nerve, and on which side?
Right cranial nerve V motor lesion; the jaw deviates in the same direction as the side of the cranial nerve V lesion
A lesion in CN X results in uvula deviation _____ (away from/toward) the lesion.
Away from
A lesion in cranial nerve XI results in weakness turning the head to the _____ (contralateral/ipsilateral) side and a shoulder droop on the _____ (contralateral/ipsilateral) side.
Contralateral; ipsilateral
The upper face receives _____ (unilateral/bilateral) upper motor neuron innervation.
Bilateral
A lower motor neuron lesion after the facial nucleus results in _____ (ipsilateral/contralateral) paralysis of the upper and lower face.
Ipsilateral
An upper motor neuron lesion between the cortex and the facial nucleus results in what pattern of paralysis in the face?
Contralateral paralysis of the lower face only
Complete destruction of the facial nucleus or its branchial efferent fibers results in what disorder?
Bell;s palsy
Bell;s palsy is characterized by peripheral _____ (ipsilateral/contralateral) facial paralysis with an inability to close the _____ (eye/mouth) on the affected side.
Ipsilateral; eye
Name six conditions that can present with Bell;s palsy; use the mnemonic Alexander Graham Bell with an STD.
AIDS, Lyme disease, Herpes zoster, Sarcoidosis, Tumors, Diabetes (remember: ALexander graHam Bell with STD)
Name the three muscles that close the jaw.
Masseter, teMporalis, and Medial pterygoid (remember: the three M;s Munch)
Which muscle opens the jaw?
The lateral pterygoid (Lateral Lowers the jaw)
Which nerve innervates all the muscles of mastication?
The trigeminal nerve (V3)
With one exception, all muscles with the root -glossus are innervated by what nerve?
The hypoglossal nerve
All muscles with the root -glossus are innervated by the hypoglossal nerve, except for which one? Which nerve is it innervated by?
The palatoglossus; it is innervated by the vagus nerve
Within which bone is the inner ear located?
The temporal bone
Name the three parts of the bony labyrinth. What fluid is the bony labyrinth filled with, and what ion is it rich in?
The cochlea, the vestibule, and the semicircular canal; perilymph; sodium (peri means around so think of extracellular fluid)
Endolymph is rich in what ion?
Potassium (endo means internal so think of intracellular fluid)
Name the four elements of the membranous labyrinth.
Cochlear duct, utricle, saccule, and semicircular canals
The vestibular apparatus detects what sensory information?
Spatial orientation
The base of the cochlea, which is most sensitive to high frequency sounds, is _____ (stiff/flexible) and _____ (wide/narrow). Which part detects low frequencies?
Stiff and narrow; low frequency is detected by the wide and flexible apex of the cochlea
Endolymph is made by what structure?
The stria vascularis
Within the inner ear, in what two places are maculae found? Maculae are important for sensing what kind of acceleration?
The utricle and the saccule; linear
Trace the path of auditory conduction from the tympanic membrane to cranial nerve VIII.
Vibration travels from the tympanic membrane through the ossicles and oval window to the basilar membrane, where bending of hair cell cilia against the tectorial membrane causes hyper- or depolarization of cranial nerve VIII
Semicircular canals contain _____, which are important for detecting angular acceleration.
Ampullae (Ampullae detect Angular acceleration)
A negative Rinne test indicates that air conduction is _____ (better/worse) than bone conduction, and implies _____ (conductive/sensorineural) hearing loss.
Worse; conductive
Someone with sensorineural hearing loss would have a _____ (positive/negative) Rinne test, and a Weber test that lateralizes to the _____ (same/opposite) ear.
Positive; opposite
The progression of hearing loss in the elderly starts with ____ (high/low) -frequency sounds and progresses to ____ (high/low) -frequency sounds.
High; low
A man with decreased hearing in his left ear is found to have a negative Rinne test and a Weber test that localizes to his left ear. What type of hearing loss does he have?
Conductive hearing loss
A woman with decreased hearing in her left ear is found to have a positive Rinne test and a Weber test that localizes to her right ear. What type of hearing loss does she have?
Sensorineural hearing loss
Which end of the cochlear membrane is narrow and stiff, and which is wide and flexible?
Like a scuba flipper, the cochlea is narrow/stiff at the base and wide/flexible at the apex
Describe the relative locations and sizes of the macula and the fovea.
The macula is a spot approximately 5 mm in diameter at the center of the retina; the fovea is at the center of the macula
The fovea has a high density of ____ (rod/cone) cells.
Cone
Retinitis is associated with what pathological appearance on fundoscopic exam?
Retinal necrosis and edema, which can lead to atrophic scarring of the retina
Reiter syndrome (reactive arthritis) can lead to inflammation of which ocular structure?
Iritis
What changes in the ciliary muscle and the lens facilitate distance vision?
The ciliary muscle relaxes and the lens flattens
Contraction of the ciliary muscle has what effect on zonular fiber tension, lens shape, and focal distance?
Ciliary muscle contraction relaxes zonular fibers, causing the lens to become more spherical and focus on closer objects
How does aging affect the lens?
Sclerosis and decreased elasticity with aging inhibit change of shape of the lens
A retinal artery occlusion would be _____ (painful/painless) and cause a(n) _____ (acute/gradual) loss of vision in a _____ (monocular/binocular) distribution.
Painless; acute; monocular
What would you expect the retina to look like on a fundoscopic exam after a retinal artery occlusion?
The retina would be pale because of lack of blood flow, but the macula would be cherry-red because it has its own blood supply: the choroid artery
Where is the aqueous humor absorbed?
The trabecular meshwork
What is the function of the canal of Schlemm?
It drains aqueous humor from the trabecular meshwork
Where is aqueous humor produced?
Ciliary process
Which muscle is involved in pupillary constriction (miosis)?
Sphincter/circular/constrictor muscle
Which muscle mediates mydriasis?
Dilator/radial muscle
Which neurotransmitter and receptor mediate mydriasis?
Norepinephrine; α1
Which neurotransmitter and receptor mediate miosis?
Acetylcholine; muscarinic (M3) receptor
What is glaucoma?
Impaired flow of aqueous humor leading to increased intraocular pressure
Increased intraocular pressure manifests as what finding on fundoscopy?
Optic disk atrophy with cupping
What are the two forms of glaucoma? What is the difference between them?
Open-angle glaucoma results from chronically obstructed outflow through the canal of Schlemm; closed-angle glaucoma results from acutely obstructed flow between the iris and the lens
Open-angle glaucoma is _____ (painful/painless), and closed angle is _____ (painful/painless).
Painless; painful
In which form of glaucoma is epinephrine contraindicated?
Closed-angle
An African-American patient presents with myopia; which form of glaucoma is most likely?
Open-angle
Why is epinephrine contraindicated in closed-angle glaucoma?
Sympathetic stimulation causes mydriasis, which exacerbates outflow obstruction
A patient presents with progressive eye pain and decreased vision; which type of glaucoma is suspected?
Closed-angle
What pathologic process underlies cataracts?
Opacification of the lens
What are the risk factors for developing cataracts?
Age, smoking, alcohol, sunlight, diabetes, trauma, and infection
What is the most common physiological cause of papilledema?
Increased intracranial pressure
How does papilledema manifest on fundoscopy?
Elevated optic disk with blurred margins
Which extraocular muscle does cranial nerve VI innervate?
The lateral rectus
Which extraocular muscle does cranial nerve IV innervate?
The superior oblique
Which muscle abducts, intorts, and depresses the eye?
The superior oblique
Identify the six extraocular muscles.
Superior rectus, superior oblique, inferior oblique, medial rectus, inferior rectus, and lateral rectus
With cranial nerve III damage, the eye would look ____ (up/down) and ____ (in/out) at rest.
Down; out
What are the physical exam findings in a patient with a unilateral CN IV (trochlear) palsy?
The patient will complain of diplopia, particularly with downward gaze; patients will characteristically tilt the head away from the side of the lesion to correct the diplopia
With cranial nerve VI damage, the eye is directed _____ (medially/laterally).
Medially
How does the chemical formula LR6SO4R3 help one remember the innervations of the extraocular muscles?
Cranial nerve VI innervates the Lateral Rectus; cranial nerve IV innervates the Superior Oblique; cranial nerve III innervates the Rest
A patient;s inability to follow the examiner;s finger toward the nose indicates a weakness in which muscle?
Medial rectus
A patient;s inability to follow the examiner;s finger upward and medially indicates a weakness in which muscle?
Inferior oblique
A patient;s inability to follow the examiner;s finger downward and medially indicates a weakness in which muscle?
Superior oblique
A patient;s inability to follow the examiner;s finger downward and laterally indicates a weakness in which muscle?
Inferior rectus
A patient;s inability to follow the examiner;s finger toward the temple indicates a weakness in which muscle?
Lateral rectus
A patient;s inability to follow the examiner;s finger upward and laterally indicates a weakness in which muscle?
Superior rectus
How does IOU help remember the test for the inferior oblique?
To test the Inferior Oblique, have patient look Up
What is strabismus?
Misalignment of the eyes
What is amblyopia?
Reduction of vision from disuse in critical period; amblyopia refers to a cortical and not an ocular phenomenon
Name three etiologies of amblyopia.
Strabismus, deprivation, unequal refractive errors
Miosis is _____ (constriction/dilation) of the pupil, mediated by ______ (parasympathetic/sympathetic) stimulation.
Constriction; parasympathetic
Which cranial nerve nucleus mediates miosis?
Edinger-Westphal nucleus
Which muscle mediates dilation (mydriasis)?
Radial muscle
Mydriasis is mediated by ______ (parasympathetic/sympathetic) innervation.
sympathetic
Sympathetic innervation of the radial muscle occurs via the _____ _____ _____ by way of the superior cervical ganglion.
Long ciliary nerve
Which cranial nerve carries signals from the retina to the pretectal nuclei?
Cranial nerve II
Activation of which nuclei within the midbrain causes the pupils to contract bilaterally?
The Edinger-Westphal nuclei
What is a Marcus Gunn pupil?
Absent bilateral pupillary constriction when light shines in the affected eye due to an afferent defect in the reflex such as optic nerve damage or retinal detachment
A patient presents with a single persistently dilated pupil. Which nerve fibers are affected? What is the likely etiology of the lesion?
The nerve fibers in the periphery of cranial nerve III (parasympathetic) are affected; this could be caused by compression (such as by a posterior cerebral artery berry aneurysm or an uncal herniation)
A patient presents with limited movement in one eye. The eye is directed downward and laterally at rest. Which nerve fibers are affected? What is the likely etiology of the lesion?
The nerve fibers in the center of cranial nerve III (sympathetic) that control ocular muscles are affected; this could be caused by vascular diseases such as diabetes, which decreases diffusion to the interior of the nerve
How does retinal detachment lead to vision loss?
Photoreceptors degenerate when the neurosensory layer of the retina is separated from the pigment epithelium
Name two possible causes of retinal detachment.
Trauma, diabetes
Degeneration of the macula causes loss of _____ (central/peripheral) vision.
Central
What is the term for a defect in a part of the visual field?
Scotoma
Which form of age-related macular degeneration is due to neovascularization?
Wet age-related macular degeneration, which progresses more rapidly than dry age-related macular degeneration
_____ (Wet/Dry) age-related macular degeneration is slow, resulting from retinal atrophy and fat deposition.
Dry
Transection of the optic nerve results in what type of visual field defect?
Complete unilateral anopia
If a patient presents with a pituitary adenoma, he or she should be screened for what type of visual field defect?
Bitemporal hemianopia
What is the name for the bundle of nerve fibers between the optic chiasm and the lateral geniculate body?
The optic tract
A lesion of the right optic tract may cause what type of visual field defect?
Left homonymous hemianopia
A lesion of Meyer;s loop (optic afferents through the temporal lobe) may result in what type of visual field defect?
Upper quadrantic anopia
A lesion of the dorsal optic radiation (parietal lobe) may result in what type of visual field defect?
Lower quadrantic anopia
A lesion at the calcarine fissure of the visual cortex may result in what type of visual field defect?
Hemianopia with macular sparing
A patient presents with an inability to gaze laterally with both eyes. When looking to the left, his left eye has nystagmus, but convergence is normal. What type of syndrome does this patient have?
Medial longitudinal fasciculus syndrome
Medial longitudinal fasciculus syndrome is associated with what disease?
Multiple sclerosis
The medial longitudinal fasciculus coordinates lateral gaze by connecting which two nuclei?
Cranial nerve VI nucleus (which controls the lateral rectus) and the medial rectus subnucleus of cranial nerve III
The right medial longitudinal fasciculus connects the _____ (left/right) nucleus of cranial nerve VI with the _____ (left/right) medial subnucleus of cranial nerve III.
Left; right; as a result, it coordinates the contraction of one eye;s medial rectus with the contraction of the other eye;s lateral rectus
When performing the caloric reflex test by irrigating the right ear with cold water, you would expect nystagmus with the slow phase to the ____ (left/right) and the quick phase to the _____ (left/right).
Right; left (remember: nystagmus follows COWS: Cold Opposite, Warm Same)
When performing the caloric reflex test by irrigating the right ear with warm water, you would expect nystagmus with the slow phase to the ____ (left/right) and the quick phase to the _____ (left/right).
Left; right (remember: nystagmus follows COWS: Cold Opposite, Warm Same)
What cells make up the inner lining of the ventricles?
Ependymal cells
A baseball hits a man’s head on the right. He seems fine at first but deteriorates fast. Which artery has been ruptured? What would the CT look like? What is the diagnosis?
Middle meningeal artery; this clinical scenario is consistent with an epidural hematoma with a lucid interval
CT scan would show a lemon-shaped appearance.
An abused one-year-old has multiple fractures. Rupture of what blood vessel leads to this kind of hematoma? What would the CT look like, and what is the diagnosis?
rupture of bridging veins
crescent/banana shape and lack of crossing of the falx
subdural hematoma
What conditions are associated with intraparenchymal hemorrhage?
Systemic hypertension, amyloid angiopathy, vasculitis, and neoplasms
What is the classic triad of symptoms in normal-pressure hydrocephalus?
Dementia, gait problems, and urinary incontinence in an elderly patient (the 3 W’s: Wacky, Wobbly, and Wet)
