The Orbit and Visual Pathways Flashcards
what bones make up the bony orbit?
frontal, zygomatic, maxilla, palatine, lacrimal, ethmoid, lesser wing of sphenoid, greater wing of sphenoid
name the foramina and fissures of the orbit?
supraorbital foramen superior orbital fissure optic canal inferior orbital fissure infraorbital foramen
what passes through the supraorbital foramen?
supraorbital nerve (from ophthalmic) and supraorbital vessels
what passes through the superior orbital fissure?
lacrimal nerve frontal nerve trochlear nerve superior oculomotor nerve nasociliary nerve inferior oculomotor nerve abducens nerve superior ophthalmic vein recurrent meningeal branch of ophthalmic artery
what passes through the optic canal?
optic nerve
ophthalmic artery
what passes through the inferior orbital fissure?
inferior ophthalmic veins
zygomatic nerve
what passes through the infraorbital foramen?
infraorbital nerve (from ophthalmic) infraorbital vessels
what are the fibrous parts of the eyeball>
sclera
cornea
what are the vascular parts of the eyeball?
iris (muscles, & pigment)
ciliary body (muscles & processes)
choroid
what are the neural parts of the eyeball?
neural retina
describe the flow of lacrimal fluid
- secreted from lacrimal gland (lacrimal nerve from ophthalmic)
- through excretory ducts onto sclera
- moves across sclera down and medially
- collects in the lacrimal puncta
- travels through the superior and inferior canaliculi
- enters the nasolacrimal sac
- moves down into the nasolacrimal duct
- exits at the inferior nasal meatus
what muscles move the superior palpebrae?
levator palpebrae superioris = oculomotor nerve orbicularis oculi (palpebral part) = facial nerve
what nuclei would be affected by a lesion in the posterior midbrain (Benedikt’s) at the level of CN3 nucleus and what symptoms would it cause?
CN3 - ipsilateral oculomotor palsy
EDW nucleus - ipsilateral fixed & dilated pupil
medial lemniscus - contralateral sensory loss (dorsal columns = vibration and proprioception)
red nucleus - contralateral hemiplegia
what nuclei would be affected by a lesion in the anterior midbrain (Weber’s) at the level of CN3 nucleus and what symptoms would it cause?
CN3 fibres - ipsilateral oculomotor palsy
PSNS fibres from EDW - ipsilateral fixed & dilated pupil
crus cerebri - contralateral hemiplegia
what peripheral disorders might cause oculomotor loss of function?
raised ICP cavernous sinus infection ICA aneurysm in the cavernous sinus PCA/SCA aneurysm sphenoid fracture
