1.45 The Orbit Flashcards
Which structures pass through the optic canal?
Optic nerve and ophthalmic artery
Which structures pass through the superior orbital fissure?
CN III, IV, V & VI and superior ophthalmic vein
Which structures pass through the inferior orbital fissure?
Infraorbital and zygomatic branches of CNV and inferior ophthalmic vein
Which muscles does the occulomotor (III) nerve innervate?
Edinger Westphal nulceus - iris and cilliary muscles contraction - parasympathetic
Occulomotor nucleus - Superior, middle and inferior rectus and inferior oblique
Which muscle does the abducens (VI) nerve innervate?
Lateral rectus
Which muscles does the trochlear (IV) nerve innervate?
Superior oblique
What is the innervation to the cilliary and iris muscles?
Parasympathetic - III Edinger Westphal nucleus
Sympathetic - Hypothalamus - T1 - Sup, Cervical Ganglion - CN V1 - dilation
Which muscles act as a lacrimal pump?
Preseptal/Pretarsal orbicularis muscles
Explain the lacrimal reflex arc…
Something irritates the cornea of the eye Nasociliary nerve Trigeminal ganglion Spinal Nucleus of V Superior Salivatory Nulcleus VII Greater Petrosal Nerve Geniculate Ganglion Pterygopalatine ganglion
What is the pupillary reflex?
Light shone in one eye
Both pupils contract
Direct & Consensual (indirect) light reflex
What is the Pathway of the pupillary reflex?
Signals to bilateral Pre Tectal Area
Signals to bilateral Edinger Westphal Nucleus
Contraction of the iris bilaterally
What is the accommodation reflex?
Focus on near or oncoming objects; pupillary constriction & convergence of eyes
What is the accommodation reflex pathway?
BILATERAL Optic nerve, Chiasm, Tract LGN Visual Cortex Pre Tectal Area Edinger Westphal Nucleus Pupillary constrictor Occulomotor nucleus - Medius rectus muscle
What is the function of the superior oblique muscle?
Depression, abduction and medial rotation
What is the function of the inferior oblique muscle?
Elevation, abduction an medial rotation
