Anatomy Flashcards
In what bone is the supraorbital notch?
Frontal bone
In what bone is the optic canal?
Sphenoid bone
In what bone is the infraorbital foramen?
Maxilla
In what direction does the optic canal lie?
Medially
Which walls of the orbit are thin?
Medial wall
Orbital floor - maxilla
What surrounds the globe in the orbit?
Periorbital fat
Name the muscle, and its parts, which makes up the external later of the eye
Orbicularis oculi
Palpebral
Orbital
What does the orbital septum do?
Separates the superficial layer from the deep.
What is the orbital septum made from?
Thickened connective tissue
What does the tarsus do?
Gives shape to eyelid
Contains tarsal glands which produces lipids that stop tears from overflowing
Where is the lacrimal gland?
Superolateral to the globe
What is the hole in the posteromedial eyelid called?
Punctum
What is the conjunctival fornix?
Angle where lower eyelid meets conjunctiva
What is the limbus?
Where sclera meets cornea
Where does the lacrimal sac drain to?
Nasolacrimal duct
Where does nasolacrimal duct empty?
Inferior meatus
What nerve innervates the lacrimal gland?
Parasympathetic of CNVII
What makes up the outer layer of eye?
Sclera
Cornea
What is the middle layer of eye?
Uvea
What is contained in the urea?
Iris
Ciliary body
Choroid
What is within the retina?
Macula
Optic disc
What are the segments of the eye?
Anterior
Posterior
Where is the anterior segment?
In front of the lens
The anterior segment is divided into anterior and posterior chamber.
What is in the anterior chamber?
Aqueous humour.
Between cornea and iris
Where is the posterior chamber?
Between iris and suspensory ligaments
What is contained in the posterior segment?
Vitreous humour
What is the iridocorneal angle?
Angle between the iris and the cornea. Different from limbus!
What does the ciliary body do?
Constricts and dilates the pupil
Where is aqueous humour produced?
Ciliary body
What is the pathway for aqueous humour?
Circulates in posterior chamber to nourish lens
Pass through pupil - nourish cornea
Reabsorbed into Canal of Schlemm
Where is canal of schlemm?
Iridocorneal angle
What is canal of Schlemm?
Scleral venous sinus
What nerve supplies the optic disc?
CNII
What is the macula?
High density of cones
What area has the most acute vision?
Fovea
What is the blind spot?
No rods or cones.
In the optic disc
Where are the retinal vessels in relation to the photoreceptors?
Anterior to photoreceptors
Where does the ophthalmic artery come from?
Internal carotid
Where do ciliary arteries supply?
Choroid - the vessels which can be seen inflammed in conjunctivitis
Which is the main artery to the retina?
Central retinal artery
What is the danger triangle?
Upper lip and external nose.
Likely to burst a vein here which could cause infection going to brain
Which veins drain the orbit?
Facial vein
Superior and Inferior ophthalmic vein
Where does the orbit drain to?
Cavernous sinus
Where do all the extra ocular muscles originate from?
Tendinous ring
Which muscle is involved with the trochlea?
Superior oblique
What is the trochlea made of?
Cartilage
What is the purpose of the suspensory ligament of the eye?
Sling which holds the eye in the orbit
When fractured, how does the zygoma rotate?
Medially
What structure is at risk if the zygoma rotates medially?
Infraorbital NVB
Where is the infraorbital NVB?
In the infraorbital canal
Where, precisely, does CN V1 innervate?
Upper eyelid
Cornea
Conjunctiva
anterior surface of nose
Where, precisely, does CN V2 innervate?
Skin of lower eyelid
Maxilla
Ala of the nose
Upper lip
What nerve supplies the angle of the mandible?
C2, C3
Where are action potentials from the cornea directed to?
Trigeminal ganglion to CN V to the pons
How does the eyelid close in the blink reflex?
Connections between CN V and CN VII means that APs are conducted to the palpebral part of orbicularis oculi
In sympathetic nerves, where doe the pre and post synaptic axon synapse?
At the ganglion in the cervical part of the sympathetic trunk
Which neurotransmitters are involved in sympathetic outflow?
Presynaptically, acetylcholine
Postsynaptically, noradrenaline
Where do presynaptic sympathetic axons exit the spinal cord?
At T1
Then ascend to the cervical sympathetic trunk
What are the 3 parts of the cervical sympathetic trunk?
Superior
Middle
Inferior ganglia
Where do the presympathetic axons synapse?
Superior cervical ganglion
Where do the post-synaptic axons go?
They enter the internal and external carotid nerves which are on the surfaces of the arteries
Which artery carries sympathetic postsynaptic axons to the eye?
Ophthalmic artery
Where does the ophthalmic artery come from?
Internal carotid artery
Anatomically, where is the superior cervical sympathetic ganglion?
On the posterior side of the superior constrictor
What is the stellate ganglion?
Fusion of the inferior cervical ganglion with the 1st thoracic ganglion
Which 4 cranial nerves are involved in parasympathetic innervation?
3, 7, 9 and 10
Which neurotransmitter is involved in synapses in parasympathetic axons?
Acetylcholine, both pre and post synaptically
Where is the parasympathetic ganglion?
Within the target organ
Which other nerves are parasympathetic supply important in?
Sacral spinal nerves
How do presynaptic parasympathetic leave the CNS?
Leave with their respective cranial nerves
What motor function does the inferior branch of CN III have?
Innervates medial and inferior rectus and inferior oblique and ciliary ganglion
What motor function does the superior branch of CN III have?
Superior rectus and levator palpebrae superioris
What are the ciliary ganglion?
Supply ciliary nerves, autonomic axons, to control the diameter of the pupil
What are the two divisions of the ciliary nerve?
Long ciliary nerve
Short ciliary nerve
What does the long ciliary nerve do?
Sympathetic and somatic sensory nerve
What does the short ciliary nerve do?
Sympathetic and somatic sensory and parasympathetic
Which ciliary nerve is involved in the blink reflex?
Long ciliary
What is the accommodation reflex?
Focussing the lens to far and near
What is the vestibulo-ocular reflex?
Ability to focus on an object while head is turned.
Which functions of the eye is parasympathetic ally controlled?
Less light into eyes by pupillary constriction
Focus on near objects
Reflex lacrimation
Which structure contains both skeletal and smooth muscle?
Levator palpebrae superioris
Which fibres are responsible for pupillary constriction?
Circular sphincter or pupillae fibres in the internal circumference
What is the consensual light reflex?
Other eye will constrict in the presence of indirect light
Which nerves are responsible for the direct and consensual light reflexes?
Afferent ipsilateral CN II connects in thalamus to produce a bilateral motor response via CN III
See rest of that lecture for rest
Light reflexes are complicated
