Anatomy: Reflexes of the Eye Flashcards
In which direction does a fractured zygoma tend to rotate
medially towards the floor of the orbit
What ligament may be damaged in a zygomatic fracture
The suspensory ligament of the eye
What can happens if the suspensory ligament lowers
diplopia
What else can be damaged in a fractured zygoma
the infraorbital NVB in the infraorbital canal
what can damage of the infraorbital canal result in
general sensory deficit of the facial skin
Which part of the mandible is not general snesory supplied by V3
the angle (supplied by C2, 3)
At what spinal cord level do presynaptic sympathetic axons from the CNS exit the spinal cord
T1 spinal nerve
Where do the sympathetic axons synapse
the superior cervical ganglion
Where do the postsynaptic sympathetic axons enter
the internal carotid nerve
the exernal carotid nerve
What carries sympathetic axons to the orbit
the ophthalmic artery (branch of the internal carotid)
What is the name given to the ganglia which is a fucion of the inferior cervical and 1st thoracic ganglia
the stellate ganglion
where do the presynaptic parasympathetic axons travel to for the eye
the ciliary ganglion
Where does the oculomotor nerve connect with the cns
the junction between the midbrain and the pons
which eye muscles are supplied by the superior branch of the oculomotor nerve
SR and LPS
which are supplied by the inferior branch of CN III
the MR, IR, and IO
What other structure does the inferior branch CN III supply
the cilirary ganglion
what do the ciliary nerves control
the diameter of the iris and thus the pupil
the refractive shape of the lense
Give the six autonomic reflexes of the eye
maximal eyelid elevation pupillary light reflex lacrimation the accommodation reflex the vestibule ocular reflex the oculocardiac reflex
What is the oculocardiac reflex
the reflec bradycardia in repsinse to tension on the exrraocular muscle or pressure on the eye
What are the sympathetic eye function
open wider
more light in
focus on far objects
emotional lacrimation
What are the parasympathetic functions
orbicularis oculi function
less light in eyes
forcus near objects
reflec lacrimation (to wash away the foreign bodies etc)
What type of muscles is contained in the levator palpenrae superioros
skeletal and smooth
What autonomic system dilates the pupil
sympathetic
what is the name of a non physiologically dilated pupil
mydriatic
What is a pin point pupil and what is it often a sign of
a fixed - no response to light pupil
opiate drug use
What is the name for a non physiologically constricted pupil
miotic
When do you get a miotic pupil
horners
What is a fixed dilated pupil often a pathological sign of
oculomotor nerve pathology
What is the afferent special sensory limb of the pupillary light reflext
the optic nerve (ipsolateral)
Wht is the motor limb of the reflex
the bilateral oculomotor nerve - hence both pupils react the same
when does the cilliary muscle relax and the lens flatten
to focus on distant objects
When does the ciliary muscle contract and the lens shortens
to focus on near objects
what is the afferent limb of the tear reflex
ophthalmic nerve
what is the efferent limb of the reflex tears
the facial nerve
