Neuro Lab Guide 6
6.05 - Review the course of the internal carotid artery from when it enters the skull to its termination.
Again, too long to write. Click here!
List the sites of aneurysms along the circle of Willis most likely to compress a cranial nerve.
Anterior communicating (~40%) - optic nerves, chiasm MCA/ICA (~20%) - optic chiasm, tract Posterior communicating, basilar bifurcation (~10%) + PCA - CN III Vertebral/Basilar (~5%) - CN VI PICA - CN VII, VIII, IX + X A tortuous superior cerebellar artery can compress the trigeminal nerve root
To what cranial nerves are the vertebral arteries most directly situated?
CN VII, CN VI...PICA to CN IX, X, VII and VIII
A man presents with diplopia, an inability to depress his LEFT eye after adduction, upper motor neuron signs on the left side and loss of discriminative touch on the left side. Localize this lesion and identify the blood vessel responsible for these findings.
The CN IV palsy should make you suspicious of a midbrain stroke affecting the trochlear nucleus, CST and the ML. Recall that the axons of CN IV cross the midline before they leave the brainstem. So injury to the right nucleus affects the left superior oblique. The most likely vascular cause would be infarct/hemorrhage in the territory of paramedian branches from the PCA - a caudal Benedikt syndrome.
How would a patient with a stroke involving the posterior inferior cerebellar artery on the right side present?
The PICA is responsible for lateral medullary syndrome. In the medulla, the PICA supplies the spinal trigeminal nucleus/tract, spinothalamic tract, restiform body, vestibular nuclei and nucleus ambiguous. If nucleus ambiguous is affected, the patient will have hoarseness, dysphagia and a diminished gag reflex. Injury to the sensory tracts will result in an alternating pattern of pain/temperature loss = IL face, CL body.
6.07 - What signs/symptoms would be present in a patient with a thrombus in the left anterior choroidal artery?
The anterior choroidal artery supplies in the internal capsule and the optic tract: blockage of this vessel would result in CL UMN signs and CL homonymous hemianopia.
6.08 - What signs/symptoms would be present in a patient with an infarct in the territory of the lenticulostriate arteries?
The lenticulostriate arteries supply the internal capsule: blockage of these vessels will affect the CST, CNT and thalamocortical fibers from the VPM and VPL.
What signs/symptoms would be present in a patient with a stroke involving the left posterior spinal artery at the level of T10?
The posterior spinal artery supplies the posterior columns, the posterior horn and the posterior root entry zone. Injury to these structures at T10 would result in complete sensory loss in the T10 dermatome (IL) and loss discriminative touch, proprioception and vibratory sense at T11 and below (also IL). It is important to recognize that the anterior and posterior spinal arteries anastomose and the degree to which any of these structures are affected depends on how extensively these vessels are connected.
List the signs/symptoms that would be associated with a stroke involving the superior division of the middle cerebral artery on the left.
The superior division of the MCA supplies the face and upper limb portion of the motor and sensory maps in primary motor and somatosensory cortex. So, motor and sensory loss would be restricted to the face and upper. This will involve the corticonuclear tract and result in CL lower facial paralysis, tongue deviation and sagging palate/deviated uvula. Additionally, the superior division of the MCA supplies Broca's area on the left side. The patient may also have an expressive aphasia.
6.06 - What neurological signs/symptoms would be present in a patient with a blockage of the right ophthalmic artery?
If the blockage is proximal to the origin of the central artery of the retina, there will be blindness in the R eye.
What artery/arteries supply the superior olivary complex?
Minutia. I just needed to have 100 questions! Regardless: short and long circumferential branches from the basilar.
What vessels provide the major blood supply to the internal capsule?
Lenticulostriates + anterior choroidal
Branches of what artery supply the calcarine sulcus? Blockage of this artery will most likely result in:
PCA CL homonymous hemianopia with macular sparring
What arteries supply the thalamus?
PCA via thalamoperforating, thalamogeniculate and posterior choroidals
6.04 - To what arteries is CN IV most intimately related during its long subarachnoid course?
Posterior cerebral, superior cerebellar, posterior choroidal
6.03 - CN III will be most directly affected by an aneurysm in which arteries?
Posterior communicating > basilar bifurcation (site of ~10% of intracranial aneurysms), PCA, superior cerebellar
List the signs/symptoms that would be associated with a stroke involving the anterior cerebral artery on the right side. List the signs/symptoms that would be associated with a stroke involving both anterior cerebral arteries (bilaterally).
R ACA = UMN signs in left LL (after shock) with sensory loss in left lower limb. Both ACA = UMN signs in both LL (after shock) with sensory loss in both lower limbs.
6.09 - Bleeding from bridging veins: who gets it? CT will most likely reveal?
Shaken babies, elderly (especially those on blood thinners)
List the signs/symptoms of an infarct involving the anterior spinal artery at L2.
This is kind of a trick question. In the medulla, cervical and thoracic cord the ASA alternate sides. In the lumbar region the ASA bifurcates at each segment. So a blockage here would impact both anterior horns (LMN signs in L2 myotome) and both spinothalamic tracts.
A man has an infarct involving the deep branches of the anterior spinal artery to the right in the medulla. What signs/symptoms would most likely be present in this patient?
This would result in a medial medullary syndrome. The anterior spinal artery, in the medulla, supplies the CST (pyramid), medial lemniscus and hypogossal nucleus/nerve. Signs/symptoms would be: CL UMN signs (after shock), CL loss of discriminative touch, proprioception and vibratory sense and a tongue that deviates to the R on protrusion (and has fasciculations).
A 67-year-old female is examined 3-weeks following a stroke. Neurological examination reveals: − a general lack of interest or concern for her condition − difficulty identifying objects (pen, door) − bilateral spastic paresis in the lower extremities, ankle clonus; normal strength in her upper extremities − bilateral Babinski signs − bilateral loss of pin-prick, proprioception and vibratory sense in the lower extremities; normal sensation in her upper extremities What structure is damaged to account for the motor signs? Is this an UMN or LMN lesion? Why are the sensory deficits so localized? Where is the lesion? What structure is damaged to account for the deficits in higher function? What blood vessel(s) are most likely involved?
What structure is damaged to account for the motor signs? Leg region of motor cortex, bilaterally Is this an UMN or LMN lesion? UMN lesion Why are the sensory deficits so localized? The leg regions of the somatosensory cortex are lesioned bilaterally. Where is the lesion? ACA territory bilaterally which includes primary motor, primary somatosensory cortex and frontal lobe. What structure is damaged to account for the deficits in higher function? Frontal lobe. What blood vessel(s) are most likely involved? ACA, bilaterally
A 58-year-old male presents to the emergency room with the chief complaint of vision loss of sudden onset; he first noticed the loss about 1-hour ago. Neurological examination reveals: − contralateral neglect − receptive dysprosody − constructional apraxia − bilateral hearing loss; Weber test is localized to midline, air > bone conduction in both ears − left-sided upper quadrant hemianopsia
What structure is damaged to account for the visual deficit? Myers loop What is contralateral neglect? Too much to write. Click here! What structure is damaged to account for the contralateral neglect? Most common is injury to the right parietal/temporal cortex. Where is the lesion? Right hemisphere What vessel is most likely responsible? Right MCA, inferior division
A 65-year-old male presents to the emergency room accompanied by his wife. She indicates that when he woke up this morning (about 45-minutes ago) he was unable to get out of bed, because of right-sided weakness. Neurological exam reveals: − right-sided homonymous hemianopsia − he cannot smile on the right side, he can wrinkle his forehead symmetrically − flaccid paresis in the right upper and lower extremities − plantar reflex is extensor on the right − loss of pin-prick, proprioception and vibratory sense on the right upper and lower extremities What structures are most likely damaged to account for the motor and sensory deficits? What structure is damaged to account for the visual deficits? Where is the lesion? Suppose a stroke was the cause of these neurological deficits, what vessel is to blame?
What structures are most likely damaged to account for the motor and sensory deficits? Left CST + CNT; medial lemniscus + spinothalamic tract or thalamocortical axons from VPL What structure is damaged to account for the visual deficits? Optic tract, lateral geniculate or optic radiations on left Where is the lesion? Internal capsule + optic tract Suppose a stroke was the cause of these neurological deficits, what vessel is to blame? Anterior choroidal artery
A 60-year-old female presents to the emergency room with her son and the chief complaints of confusion and vision loss. These problems arose suddenly about 1- hour ago. Physical examination reveals a right-sided upper quadrant hemianopsia. Imaging reveals an infarct in the region indicated in the figure to the right. What vascular territory is indicated [be as specific as possible!] What part of the visual system is affected to account for this pattern of vision loss? What higher-function will most likely be affected?
What vascular territory is indicated [be as specific as possible!] L MCA, inferior divison What part of the visual system is affected to account for this pattern of vision loss? Optic radiations, Myers loop What higher-function will most likely be affected? Receptive aphasia
A 62-year-old male presents to the emergency room with the chief complaints of neck pain, dizziness, numbness on his face and hoarseness. History reveals these deficits came on suddenly about 30-minutes ago. A careful neurological examination reveals: − pain in the left suboccipital region − left-sided ptosis with a constricted, unreactive pupil − hoarseness, sagging palate on the left − weak gag reflex − decreased pin-prick sensation on the left side of the face − decreased pinprick and temperature sensation in the right limbs and trunk below the neck − unsteady gait, falling towards the left side where is the lesion what blood vessel is involved
Where is the lesion? Left lateral medulla (lateral medullary syndrome) What blood vessel is involved? PICA (or vertebral inferior to PICA)
A 67-year-old female presents to the emergency room with her daughter and the chief complaint of left-sided weakness. The daughter claims that when her mother woke up this morning, she was unable to get out of bed. A careful neurological examination reveals: − her tongue deviates to the right on protrusion − weakness on the left; all muscle stretch reflexes are 1/4 on the left (2+/4 on the right) − Babinski sign on the left − loss of discriminative touch on her left upper limb, trunk and lower limb where is the lesion? what blood vessel serves this area
Where is the lesion? Medulla - medial medullary syndrome What blood vessel serves this area? Anterior spinal artery (perforating branches)
An 80-year-old male presents to the emergency room with his wife. History reveals that the man fell this morning while in the shower. His wife found him in the tub awake and alert but unable to move his left arm and leg. His wife indicates that he has had some difficulty maintaining his balance recently and that last night during dinner he dropped his fork [with his left hand] and had difficulty picking it up. The man is able to speak and can give a detailed account of what happened to him this morning. He is aware of his surroundings and his condition. A careful neurologic examination reveals: − his eyes continually deviate to the right − he cannot smile on the left side; he can wrinkle his forehead symmetrically; dysarthria − tongue deviates to left on protrusion with no fasciculations − weakness in left upper limb and hip − biceps and brachioradialis reflexes are 1/4 on the left − loss of pin-prick and vibratory sense on the left face, left arm, shoulder and chest − ten days later he has spastic weakness and 3+ reflexes in his left upper limb where is the lesion which artery has likely been occluded to produce the above signs
Where is the lesion? Right frontal lobe Which artery has likely been occluded to produce the above signs? R MCA, superior division
A 49-year-old female presents to the emergency room following a "blackout" with the chief complaints of double-vision and left-sided weakness. A neurological examination reveals the following signs: − her right eye is deviated laterally and on abduction cannot be elevated or depressed − ptosis on the right − her right pupil is dilated and unresponsive to light − she cannot smile on the left, but can wrinkle her forehead symmetrically − her tongue deviates to the left on protrusion but shows no fasciculations − flaccid paresis of the left upper and lower extremities − plantar reflex is flexor on the right, extensor on the left where is the lesion which artery has likely been occluded to produce the above signs
Where is the lesion? [Locate as precisely as possible] R midbrain What vessel has been occluded to produce this lesion? Paramedian branches from the basilar