Anatomy (2) Flashcards
After orbital trauma - where does the fractured zygoma tend to rotate towards?
Medially towards floor of orbit
What is the name for the thick facial sling that holds the eye just above the floor of the orbit?
Suspensory ligament of the eye
What can a drop of the suspensory ligament of the eye cause>
Diplopia
What nerve gives general sensory nerve supply to the upper eyelid, cornea, all conjunctiva and the skin of the root/bridge/tip of the nose?
Opthalmic V1
What nerve gives general sensory nerve supply to the skin of the lower eyelid, skin over maxilla, skin of the ala of the nose and the skin/mucosa of the upper lip?
V2 Maxillary
What is the infraorbital nerve a branch of?
V2
What nerve gives general sensory nerve supply to the skin over the mandible and temporomandibular joint?
V3 Mandibular
What nerve gives general sensory nerve supply to the angle of the mandible?
C2, C3 spinal nerves
If you touch the cornea to initiate a blink reflex - what nerve sets up action potentials?
Trigeminal V1 - then goes to pons of brain
In the blink reflex - what are the two nerves that have CNS connections?
CN V and CN VII
In the motor reflex of the blink reflex - where are action potentials conducted?
Peripherally in CN VII to the eyelid part of orbicularis oculi
What are the four steps on the presynaptic sympathetic axons from the CNS coirse?
1, Descend in the spinal cord and then
- Exit the spinal cord in T1 spinal nerve and then
- Ascend within the sympathetic trunk and then
- Synapse in the superior cervical sympathetic ganglion
What do the post synaptic sympathetic axons enter ?
The internal carotid nerve and the external carotid nerve. Then pass onto surfce of internal anad external carotid ateries.
What artery carries sympathetic axons into the orbit?
Opthalmic artery
What do the inferior cervical and 1st thoracic ganglia often fuse to form?
The stellate ganglion
What 4 cranial nerves contain presynaptic parasympathetic axons?
3, 7, 9 and 10 plus sacral spinal nerves
Where are the ganglions located for parasympathetic axons?
Within the organ
What ganglion in the orbit collects presynaptic parasympathetic axons from CN III?
Ciliary ganglion
What CN gives parasympathetic axons to the lacrimal gland, submandibular and sublingual salivary glands?
Facial
Where does the CN III connect with the CNS?
At junction between midbrain and pons
What is the base of scull part of course for CN III?
Superior orbital fissure
What does the superior branch of CN III supply?
Superior rectus and levator palpebrae superioris
What does the inferior branch of CN III supply?
Medial rectus, inferior rectus, inferior oblique and the ciliary ganglion
What do the ciliary nerves supply autonomic axons to?
Control the diamter of the iris and the refractive shape of the lens
What nerve synpses in the ciliary ganglion?
Inferior branch of CN III
What does the long ciliart nerves form the first part of?
Afferent limb of the blink reflex
What nerve from CN III is somatic sensory, parasympathetic and sympathetic?
Inferior branch of CN III leading to SHORT CILIARY NERVE
What nerve from CN III is somatic sensory and sympathetic?
LONG CILIARY NERVE
What is the name for the reflex that focusses the lens?
Accommodation reflex
What is the vestibulo-ocular reflex?
Turns the eyes in the opposite direction to a head movement. CNS connections between CN VIII & CN III, IV and VI
What is the oculocardiac reflex?
Reflex bradycardia in response to tensio on the extraocular muscles or pressure on the eye. CNS connections between CN VI and CN X
What two types of muscles are contained in levator palpebrae superioris?
Skeletal and smooth
What do sympathetics do to the pupil?
Dilate it - in dim light
What is a non-physiologically enlarged pupil called?
a mydriatic pupil
Where is the mobile insertion of the radially arranged dilator pup[illae fibres all around?
The internal circumference of the iris
Where is the fixed origin of the radially arranged dilator pupillae fibres all around?
The external circumference of the iris
What controls constriction of the pupil?
Parasympathetics - in bright light
What is a non-physiologically constricted pupil called?
A miotic pupil - component of horners syndrome
What is a blown pupil - fixed dilated, a serious pathological sign of?
CN III pathology. inhibiting the pupilary constricting action of parasympathetic axons in the ciliary nerves
How are the encircling arrangement of teh sphincter pupillae fibres done?
All around the internal circumference of the iris
The sensory limb of the loight reflex is the ipsilateraly CN II - where does it connect in CNS?
In the thalamus
What is the motor limb of the light reflex?
Bilateral via CN III
How many neurone chains are in the pupillary light reflex?
4 neurones
What number of neurone in the pupillary light reflex is this: the retinal ganglion cells pass via the ipsilateral optic nerve to decussate in the optic chiasm then synapse in the pretectal nucelus in the midbrain
1st neruones
What number of neurone in the pupillary light reflex is this: located entirly within the midbrain and connect the pretectal nucleus to the next synapse in the Edinger Westphal nucleus (location of the cell bodies of the parasympathetic axons of CN III)
2nd neurones (bilateral)
What number of neurone in the pupillary light reflex is this: pass from the EW nucleus, via CN III then its inferior division, to synapse in the ciliary ganglion
3rd neurones (bilateral)
What number of neurone in the pupillary light reflex is this: Course in the short ciliary nerves to the sphincter pupillae muscles
4th neurones
What structure connects the circumferences of the lens and the ciliary body?
Suspensory ligament of the lens
In far vision what does the ciliary body do?
Relaxes - the ligament tightens and the lens flattens to focus on the distance
In near vision what does the ciliary muscle do?
Contract (parasympathetic) the ligament relaxes and the lens becomes spherical to focus on “reading”
In the accomodation relfex: what does the bilateral piupillary constriction do?
Prevents diverging light rays from hitting the periphery of the retina and resulting in a blurred image
In the accomodation reflex: what does bilateral convergence do - medial rotation of both eyes?
Simultaneous movement of both eyes in opposite directions to obtain or maintain single binocular vision
In the accomodation reflex: what does bilateral relaxation of the lens do?
The lens becomes spherical due to contraction of teh ciliary muscles
What tears are important in corneal health?
Basal tears
What tears clean/nourish and hydrate the avascular cornea and contain lysozymes?
Basal tears
What is the afferent limb of the reflex tears?
CN V1
What is the efferent limb of teh reflex tears?
Parasympathetic axons originating from CN VII
