I.
Components of the Visual System
A. The specialized sense of visual perception is the result of the visual pathway
originating at Cranial Nerve II (optic nerve)
B. The control of the eye movements both extraocular and intraocular muscles
resulting from Cranial Nerve III (oculomotor nerve), CN IV (trochlear nerve)
and CN VI (abducens nerve)
C. Pupillary action is under the sole control of the autonomic nervous system
II.
The Visual Pathway
A. The optic nerve is not, technically speaking, a nerve but is an extension of the
brain with the same three menningial layers: dura, arachnoid, and pia. Thus,
the optic nerve is prone to diseases that are unique to the central nervous
system including increased intracranial pressure and the effects of multiple
sclerosis
B. Neuropathologies of the visual pathway
1. Mass lesions
2. Multiple Sclerosis
3. Increased intracranial pressure
4. Cerebrovascular disease
C. The anatomy and pathologies of the intra-orbital optic nerve
D. The anatomy and pathologies of the optic canal and peri-chiasmal area
1. CN II exits the obit via the optic canal, along with the ophthalmic
artery
2. Significant adjacent structures includes the pituitary gland
E.
The anatomy and pathologies of the optic radiations
1. Significant adjacent structures include the ventricles and the thalamus
F.
The anatomy and pathologies of the visual cortex
1. Vascular
2. Retinotopic organization
III.
The Oculomotor Pathway
A. All extraocular muscles are innervated by either CN III, CN IV or CN
B. VIDEO: CN III palsy
C. VIDEO: CN IV palsy
D. VIDEO: CN VI palsy
E.
The anatomy and pathologies of the intraorbital CNs III, IV, and VI
F.
The anatomy and pathologies of the cavernous sinus
1. What’s a “cavernous sinus” and why do I care?
2. “Cavernous sinus syndrome”
G. The anatomy and pathologies at the Circle of Willis
1. Aneurysms and CN III
H. The anatomy and pathologies of the interpeduncluar cistern
1. What’s a “cistern” and why do I care?
I.
The anatomy and pathologies of the brainstem
1.
2.
3.
IV.
Brainstem functions, “what doesn’t it do?”
The MLF, in a nut-shell
VIDEO: internuclear ophthalmoplegia
The Pupillary Pathway
A. The anatomy and the pathologies of the afferent pathway
1. VIDEO: normal pupillary light response
2. The anatomy from CN II to the midbrain
3.
VIDEO: animation of the afferent pupillary pathway
B. The anatomy of the relative afferent pupillary defect
1. VIDEO: animation of the relative afferent pupillary defect
2. VIDEO: clinical presentation of a relative afferent pupillary defect
C. The anatomy and pathologies of the efferent pupillary pathway
1. VIDEO: animation of the normal pupil response
2. The anatomy anisocoria
a) Non-neurologic
b) Sympathetic lesions
VIDEO: schematic of Horner’s syndrome
VIDEO: clinical presentation of Horner’s syndrome
c) Parasympathtic lesions
CN III lesions
VIDEO: schematic of Adie’s
VIDEO: clinical presentation of Adie’s tonic pupil
VIDEO: schematic of physiologic anisocoria