Flashcards in Anatomy Deck (91):
What are the bones and features of the bony orbit?
Orbital frontal plate
Orbital ethmoid plate
Superior orbital fissure
What shape is the bony orbit?
What makes up the external eyelid?
Orbital and palpebral parts
What is the apex?
Where the optic canal is
Where is the optic canal?
Where does the vasculature pass through? *?*
What sits beneath the external layer of the eye?
Sheet of fascia - Helps prevent infection spread
What glands sit above and below the eye?
What do tarsal glands secrete?
What muscle attaches to the superior tarsus?
Levator palpebrae superiolis
What ligaments pull the tarsus to the side to give it its shape?
Lateral/medial palpebral ligament
What covers the iris?
What is a limbus?
A corneoscleral junction
What covers the sclera?
What is the pink/orangey bit at the corners of the eye?
Where do tears pass into?
a Puncta (openings)
What provides the eye with nourishment?
What is the conjunctival fornix?
Where the conjuctiva over the lower eyelid and over the sclera meet
What does the lacrimal gland secrete and what supplies it?
CN VII parasym
Where do tears drain to?
Canaliculi and lacrimal sac, down a nasolacrimal duct into the inferior meatus (nose)
What is the coloured part of the eye?
What is the pupil?
What are corneal reflections?
Does the cornea have a greater curvature?
What makes up the 2 parts of the fibrous outer layer of the eye?
Sclera - musslce attachment
Cornea - 2/3 refractive power
What makes up the uvea (vascular layer of the eye)
iris - pupil diameter
ciliary body - controls iris, shape of lens and secretion of aqueous humour
Choroid - nutrition and gas exchange
What is refractive power?
Ability to focus light
What is the inner layer of the eye?
What is the anterior segment if the eye?
Anterior chamber is between cornea and iris, contains aqueous humour
Posterior chamber is between iris and suspensory ligaments, contains aqueous humour
What is the posterior segment of the eye?
behind lens, 2/3rds of eye
contains vitreous body which has vitreous humour.
Vitreous body is a common location for floaters
What is a clouding of the lens?
Where is aqueous circulated?
then posterior chamber - nourishes lens
passes through pupils
then reabsorbed into sclera venous sinus
What angle is involved with glaucoma?
angle between the Iris and the cornea
What can cause ishaemia of the retina?
Raised intra-ocular pressure
Can be caused by increased fluid level in the eye
What makes up the retina?
What is the optic disc?
Point of CN 2 formation
Only point of entry/exit for vessels
What is the macula?
Greatest density of cons
What is the fovea?
centre of the macula
Depression, diameter of 1.5mm
area of most acute vision
How do you look at the back of the eye?
What causes monocular blindness?
Complete interruption of flow of the central artery (end artery) or vein
Are the optic canal and the optic disc closely anatomically related?
What are the layers of the retina?
Post to Anterior:
2. ganglion cells
3. axons of the ganglia
Where do the retinal veins/arteries lie in relation to the retina?
Where do objects in the right visual field go to be processed?
Left primary visual cortext
Where do the vision pathways cross?
The optic chiasma
What is the Lateral geniculate nucleus (LGN)
Part of the visual pathway in the thalamus
What is the main blood supply of the eye?
Opthalmic artery branch of the internal carotid artery
Where does the opthalmic artery pass through?
What is the problem with the retinal artery?
It is an end artery
Where does the inferior opthalmic vein mainly drain into?
Superior opthalmic vein
Where does the orbit drain into?
Facial vein (valveless vein)
How many extraocular skeletal muscles are there?
What are the 4 rectus muscles?
Where do the rectus muscle originate from and attach to?
Common tendinous rung to the sclera
What are the two oblique muscles?
Where do the oblique muscles insert into?
What does the levator palpebrea superioris do?
Lifts the upper eyelid
What innervates the lateral rectus?
CN VI Abducents
What innervates the superior oblique?
CN IV Trochlear
What innervates the other muscles of the eye?
CN III Oculomotor
What eye movements are along the vertical axis?
Direction of gaze
What eye movements are along the transverse axis?
direction of gaze
What eye movements are along the anteroposterior axis?
superior pole of the eyeball
Where is the apex of orbit?
*Different from optical axis*
What eye muscles don't have secondary movements?
Medial and lateral rectus
Where do the secondary movements occur?
From the primary position
How do you check the nerve supply of the eye?
Do eye movements one by one
What does the lateral rectus do?
Abduct the eyeball only
- CN VI - abducents
What does the superior rectus do?
elevate the eyeball only when the eyeball is abducted
CN III - oculomotor
What does the inferior rectus do?
Depress the eye when the they eye is in abduction
CN III - oculomotor
What does the medial rectus do?
Adduct the eye
CN III 0 oculomotor
What does the inferior oblique do?
Elevates the eyeball only when the eye is in adduction
CN III oculomotor
What does the superior oblique do?
Depresses the eye only when the eye is in adduction
CN IV trochlear
What gives pure elevation of the eyes?
Superior rectus and inferior oblique
They are antagonists - act against each other to lift the eye
What gives pure depression?
Superior oblique and inferior rectus
Antagonists as they work together to lower the eye
Where does the eyeball sit?
The suspensory ligament of the eye
What is diplopia?
Where does the suspensory ligament of the eye attach to?
What can result from damage to the infraorbital canal?
General sensory deficit of the facial skin
Where does the zygoma rotate when fractured?
Medially towards the floor of the orbit
What does CN V1 supply
(opthalmic) general sensory of skin
What does CN V2 supply? (maxillary) general sensory of skin
ala of nose
What does CN V3 supply? (mandibular)
general sensory of skin
except angle of the mandible supplied by C2 C3 spinal nerves
What is the corneal reflex?
What is the afferent limb of the relfex?
What is the efferent limb of the reflex?
Where are action potentials conducted in the corneal reflex?
Centrally via CN V1 to the trigeminal ganglion then in CN V to the pons
Where are action potentials conducted peripherally in the corneal reflex?
In CN VII to the eyelid and orbicularis oculi
What does the presynaptic axon release?
Acetylcholine at the synapse
What does the postsynaptic axon release?
Noradrenaline at the organ to stimulate the organ