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I. THE VISUAL PATHWAY
A. CN II, orbital segment and the optic canal
1. Anatomy of intra-orbital CN II
2. CNS-pathology of the intra-orbital CN II
a. Increase intracranial pressure: papilledema
b. Mass/compressive lesions: optic nerve gliomas
c. Multiple Sclerosis: optic neuritis
d. Vascular events: ischemic optic neuropathy
3. Clinical presentation/findings
a. Signs/symptoms, visual field defects, MRI, lumbar puncture
B. CN II, peri-chiasmal segment
1. Anatomy of peri-chiasmal CN II
a. Adjacent structures: pituitary gland, sella turcica
2. Pathology of the peri-chiasmal optic nerve
a. Mass/compressive lesions: optic nerve gliomas
b. Vascular events: rare
3. Clinical presentation/findings
a. Signs/symptoms, visual field defects (pre-chiasmal, chiasmal, post-chiasmal), MRI
C. CN II, optic tracts and their termination at the thalamus
1. Anatomy of the optic tracts and adjacent structures
a. Adjacent structures: thalamus, LGB, superior colliculus
b. Diversion of the pupillary fibers
2. Pathology of the optic tracts
a. Mass/compressive lesions: rare
c. Vascular event: rate
3. Clinical presentation/findings
a. Signs/symptoms, visual field defects, MRI
D. CN II, optic radiations (thalamus to the visual cortex)
1. Anatomy of optic radiations
a. Temporal lobe, Meyer’s loop, parietal lobe, lateral ventricles, occipital lobe
2. Pathology of the optic radiations
a. Mass/compressive lesions: abscess
b. Vascular events: most common (ischemic events)
3. Clinical presentation/findings
a. Signs/symptoms, visual field defects, MRI
E. Primary Visual Cortex (i.e. striate cortex, Brodmann’s Area 17)
1. Anatomy of the visual cortex and adjacent structures
a. Visual field map within the visual cortex, calcarine fissure, vasculature
2. Pathology of the optic tracts
a. Mass/compressive lesions
b. Vascular events: ischemic, hemorrhagic
3. Clinical presentation/findings
a. Signs/symptoms, visual field defect, MRI
F. Beyond the visual cortex (i.e. extrastriate cortex, visual association cortex)
1. Anatomy and functions of the visual association cortex
2. Pathology of the Visual Association Cortex: rare
3. Clinical presentation/findings
II. THE OCULAR MOTOR PATHWAY
A. CN III, IV, V (ophthalmic division), VI within the orbit
1. Anatomy of the intra-orbital CN III, IV, V (ophthalmic division), and VI
2. CNS-pathology of the intra-orbital nerves III, IV, V (ophthalmic division), and VI
a. Microvascular lesions (esp. CN III)
b. Multiple Sclerosis?
3. Clinical presentation/findings
a. Signs/symptoms, MRI
B.
CN III, IV, V (ophthalmic division), and VI at the superior orbital fissure and
within the cavernous sinus
1. Anatomy of the superior orbital fissure and cavernous sinus
a. Adjacent structures: sella turcica, carotid artery, nasopharynx
2. Pathologies of the cavernous sinus
a. Fistula, aneurysm, carcinoma, Tolosa-Hunt syndrome, tumors, trauma
3. Clinical presentation/findings
a. cavernous sinus syndrome, MRI
C. CN III, IV, V (ophthalmic division) and VI dorsal to the cavernous sinus
1. Anatomy of the posterior middle fossa
a. Adjacent structures: tentorial incisura, circle of Willis
2. Pathology of CN III, IV, and IV at the middle fossa
a. Cerebral edema, increased intracranial pressure, downward displacement of the brain
c. Vascular events: microvascular ischemic events
3. Clinical presentation/findings
a. Pupil dilation associated with loss of consciousness
D. CN III, IV, VI, at the interpeduncular/prepontine cisterns
1. Anatomy of the interpeduncular/prepontine cisterns
a. Adjacent structures: midbrain, pons, petrous ridge, Dorello’s canal
2. Pathology of CN III, IV, and IV at the Interpeduncular/Prepontine Cisterns
a. CN IV vulnerable to contracoup forces
b. CN VI vulnerable to “stretching” with downward displacement of the brainstem
c. Vascular events: microvascular ischemic events
3. Clinical presentation/findings
a. Signs/symptoms, MRI
E. CN III, IV, and VI, the fascicles and nuclei
1. Anatomy of the brainstem (Midbrain and Pons)
a. Adjacent structures: pathways and centers for breathing, coordinated voluntary
muscle movements, auditory and visual reflexes pathways, control of “wakefulness”
2. Pathology of CN III, IV, and VI within the brainstem
a. Mass lesion
b. Vascular events
3. Clinical presentation/findings: hemitremor, hemiparesis
F. Internuclear Ophthalmoplegia
1. Anatomy of Internuclear pathways connecting CN III, CN IV, CN VI i.e. the medial
longitudinal fasciculus (MLF)
2. Pathology of the MLF
3. Clinical presentation/findings
a. External exam video clip
G. Supranuclear Ophthalmoplegia
1. Anatomy of the ocular motor system beyond the motor nuclei and the MLF
2. Pathology of supranuclear pathways
3. Clinical presentation/findings
a. External exam video clip
III. THE PUPILS
1. Anatomy of the neural pathways
a. The afferent pathway
b. The efferent sympathetic pathway
c. The efferent parasympathetic pathway
2. Pathology of the pupils
a. The afferent pathway
b. The efferent sympathetic pathway: CNS (brain and spinal cord), preganglionic
lesion, postganglionic lesion
c. The efferent parasympathetic pathway: midbrain lesions, CN III lesions
3. Clinical presentation/findings
a. Horner’s syndrome