Neurology Topics

Question 1

Foville’s syndrome

Answer 1

Pontine lesion causing ipsilateral horizontal gaze paresis due to involvement of the paramedian pontine reticular formation (PPRF), ipsilateral facial nerve palsy of lower motor neuron type due to involvement of the facial nucleus, and contralateral hemiparesis due to involvement of the corticospinal tract

Question 2

Weber’s syndrome

Answer 2

Midbrain lesion causing contralateral hemiparesis due to involvement of the corticospinal tract traversing the cerebral peduncle, contralateral facial weakness of the upper motor neuron type, and ipsilateral oculomotor nerve palsy (ptosis, double vision due to palsy of medial rectus, superior rectus, inferior rectus, and inferior oblique)

Question 3

Inferior cerebellar peduncle

Answer 3

Traverses from rostral medulla to cerebellum
Carries info from vestibular nuclei, spinal cord, brainstem reticular formation, and inferior olivary complex to the cerebellum
Conveys fibers from the cerebellum to the vestibular nuclei and brainstem reticular formation

Question 4

Tarsal muscle of Muller

Answer 4

Innervated by sympathetics
Loss of sympathetics causing Horner syndrome causes only partial ptosis because levator muscle of eyelid is still intact and innervated by CN III

Question 5

Wallenberg’s syndrome

Answer 5

Caused by stroke in the vertebral artery causing lateral dorsal medulla to be knocked out. Affects:

• Vestibular nuclei: vomiting, vertigo, nystagmus
• Inferior cerebelar peduncle: ipsilateral ataxia, dysmetria, dysdiadokokinesia
• Lateral spinothalamic tract: contralateral deficits in pain and temp from body
• Spinal trigeminal nucleus and tract: ipsilateral deficit in pain and temp from face
• Nucleus ambiguus: ipsilateral laryngeal, pharyngeal, and palatal hemiparesis causing dysphagia, hoarseness, diminished gag reflex
• Descending sympathetic fibers: ipsilateral Horner’s syndrome with ptosis, miosis, and anhydrosis

Question 6

Pupillary reflex

Answer 6

Ganglion cells → optic nerve → optic chiasm → optic tracts → pretectal nucleus of dorsal midbrain → bilateral investment of edinger-westphal nuclei of the oculomotor nerve nuclear complex → oculomotor nerve → ciliary ganglion → short ciliary nerves → iris sphincter

Question 7

Visual system pathway

Answer 7

Ganglion cells → optic nerve → optic chiasm → optic tract → lateral geniculate nucleus of the thalamus → optic radiations → primary visual cortex

Question 8

Frontal eye fields

Answer 8

Brodmann’s area 8
Area of cerebral cortex just anterior to the motor facial representation of the precentral gyrus
Pathway for horizontal gaze begins here, the pathway is called the frontopontine tract and descends through internal capsule, then crosses in caudal midbrain to reach the paramedian pontine reticular formation on the contralateral side