Anatomy Flashcards
The Orbit: The boundaries of the orbit are formed by how many bones?
7
The Orbit: Roof of the Orbit is formed by what? (2)
Frontal Bone
Sphenoid Bone
The Orbit: Floor of the Orbit is formed by what? (3)
Maxilla
Palatine Bone
Zygomatic Bone
The Orbit: Medial wall is formed by what? (4)
Ethmoid bone
Maxilla bone
Lacrimal bone
Sphenoid bone
The Orbit: Lateral wall is formed by what? (2)
Zygomatic bone
Sphenoid bone
The Orbit: Shape of the orbit
Pyramidal shape
The Orbit: Apex points in what direction?
Posteriorly
The Orbit: Blow out fractures impact what walls?
Medial and orbital wall
The Eyelid: Orbicularis Oculi - Deep to what?
Skin and connective tissue
The Eyelid: Orbicularis Oculi - Three distinct parts (3)
Palpebral part
Lacrimal part
Orbital part
The Eyelid: Orbicularis Oculi - Palpebral part function
Gently closes the eyelids
The Eyelid: Orbicularis Oculi - Lacrimal part function
Involved in the drainage of tears
The Eyelid: Orbicularis Oculi - Orbital part function
Tightly closes the eyelids
The Eyelid: Orbicularis Oculi - Innervated by what?
CN VII - Facial Nerve
The Eyelid: Tarsal Plates - Located where?
Deep to the palpebral region of the orbicularis oculi muscle
The Eyelid: Tarsal Plates - Two plate names
Superior tarsus and Inferior tarsus
The Eyelid: Tarsal Plates - They act to form what?
Scaffolding of the eyelid
The Eyelid: Tarsal Plates - Composed of what?
Dense connective tissue
The Eyelid: Tarsal Plates - Superior tarsus acts as an attachment site of what?
Levator palpebrae superioris
The Eyelid: Tarsal Plates - What glands are located in the tarsal plates?
Meibomian Glands
The Eyelid: Tarsal Plates - Meibomian Glands function
Secrete oily lipid substance that slows the evaporation of the eyes tear film and prevents the eyelids from sticking together when closed
The Eyelid: Tarsal Plates - Orbital septum extends from where?
Either tarsus to the orbital margin
The Eyelid: Tarsal Plates - Function of the orbital septum
Prevents the spread of infection between the superficial and deep parts of the orbit
The Eyelid: Which muscle elevates the upper eyelid?
Levator palpebrae superioris muscle
Lacrimal Apparatus: Lacrimal gland produces what?
Lacrimal fluid
Lacrimal Apparatus: Innervation
CN VII - parasympathetic innervation
Lacrimal Apparatus: Fluid is pushed towards what?
Medial angle
Lacrimal Apparatus: Position of Lacrimal Gland
Superolaterally
Lacrimal Apparatus: Once the fluid gets to the medial angle where does it drain to?
Lacrimal puncta
Lacrimal Apparatus: Eventually the fluid reaches what structure?
Inferior meatus
Extraocular Muscles: How many are there?
7
Extraocular Muscles: Which groups are responsible for eye movement?
Recti and oblique muscles
Extraocular Muscles: Which group is responsible for superior eyelid movement?
Levator palpebrae superioris
Extraocular Muscles: What are the 7 muscles?
Levator palpebrae superioris
Superior oblique
Inferior oblique
Superior rectus
Medial rectus
Lateral rectus
Inferior rectus
Extraocular Muscles: Recti Muscles - Direction
Straight - from origin to attachment
Extraocular Muscles: Recti Muscles - 4 muscles
Superior rectus
Medial rectus
Lateral rectus
Inferior rectus
Extraocular Muscles: Recti Muscles - Origin
Common tendinous ring for all the recti muscles
Extraocular Muscles: Recti Muscles - Insertion point
Sclera
Extraocular Muscles: Oblique Muscles - Muscles (2)
Inferior oblique
Superior oblique
Extraocular Muscles: Oblique Muscles - Origin of Superior oblique muscle
Sphenoid bone
Extraocular Muscles: Oblique Muscles - Origin of the Inferior Oblique muscle
Orbital plate of the maxilla
Extraocular Muscles: Oblique Muscles - Insertion
Sclera
Extraocular Muscles: Oblique Muscles - The tendon of the superior oblique passes through what before inserting onto the sclera?
Trochlea
Extraocular Muscles: Levator Palpebrae Superioris Muscle - Origin
Lesser wing of the sphenoid
Extraocular Muscles: Levator Palpebrae Superioris Muscle - Insertion
Skin and tarsus of the superior eyelid
Extraocular Muscles: Levator Palpebrae Superioris Muscle - Superior Tarsal Muscle contains a collection of what? And what is its name?
Smooth muscle fibres - Mueller’s Muscle
Extraocular Muscles: Levator Palpebrae Superioris Muscle - Muellers Muscle is innervated by what?
Sympathetic fibres from the superior cervical ganglion
Extraocular Muscles: Levator Palpebrae Superioris Muscle - Innervation
CN III
Horners Syndrome: Involves what muscle?
Muellers Muscle
Horners Syndrome: Pathophysiology of ptosis
Compromised sympathetic innervation to the Muellers Muscle
Extraocular Muscles: Innervation of Lateral Rectus Muscle
CN VI - Abducens
Extraocular Muscles: Innervation of Superior Oblique Muscle
CN IV - Trochlear Nerve
Extraocular Muscles: What is the innervation of all of the muscles apart from LR and SO?
CN III
Eyeball Movement: Vertical axis controls what? (3)
Abduction
Adduction
Direction of gaze
Eyeball Movement: Transverse axis controls what? (3)
Elevation
Depression
Direction of gaze
Eyeball Movement: Anteroposterior Axis controls what? (3)
Intorsion - medial rotation
Extorsion - lateral rotation
Superior pole of the eyeball
Eyeball Movement: Which muscles do not have secondary movements? (2)
Medial rectus
Lateral rectus
Eyeball Movement: Primary position
Where the gaze is directed forward
Eyeball Movement: Testing Extraocular Muscles - Superior Rectus movement
Look lateral and upward
Eyeball Movement: Testing Extraocular Muscles - Inferior Rectus movement
Look lateral and downward
Eyeball Movement: Testing Extraocular Muscles - Lateral Rectus Movement
Look laterally
Eyeball Movement: Testing Extraocular Muscles - Medial Rectus Movement
Look medially
Eyeball Movement: Testing Extraocular Muscles - Inferior Oblique Movement
Look medially and upward
Eyeball Movement: Testing Extraocular Muscles - Superior Oblique Movement
Look medially and downward
Eyeball Movement: Lateral Rectus - Function
Abducts the eyeball
Eyeball Movement: Lateral Rectus - Innervation
CN VI - Abducens
Eyeball Movement: Lateral Rectus - Brings line of gaze into what?
Same plane as the superior rectus and inferior rectus
Eyeball Movement: Superior Rectus - Function
Can only elevate when in abduction
Eyeball Movement: Superior Rectus - Innervation
CN III - Oculomotor
Eyeball Movement: Inferior Rectus - Function
Can only depress when in abduction
Eyeball Movement: Inferior Rectus - Innervation
CN III - Oculomotor
Eyeball Movement: Medial Rectus - Function
Adducts the eyeball
Eyeball Movement: Medial Rectus - Innervation
CN III - Oculomotor
Eyeball Movement: Medial Rectus - Brings line of gaze into what?
Same plane as Superior Oblique and Inferior Oblique attachments
Eyeball Movement: Inferior Oblique - Function
Can only elevate the eyeball when in adduction
Eyeball Movement: Inferior Oblique - Innervation
CN III - Oculomotor
Eyeball Movement: Superior Oblique - Function
Can only depress the eye when in adduction
Eyeball Movement: Superior Oblique - Innervation
CN IV - Trochlear
Eyeball Movement: Mechanics behind the pure elevation of the eyeball
Involves the superior rectus and inferior oblique synergystically elevates the eyes by working antagonistically as rotators
Eyeball Movement: Mechanics behind the pure depression of the eyeball
Involves the superior oblique and inferior rectus synergystically depressing the eyes by working antagonistically adducting or abducting
Sympathetic Innervation: Origin
Autonomic centres of the brain
Sympathetic Innervation: Exits spinal cord where?
T1-L2
Sympathetic Innervation: Pass into all spinal nerves via what?
Anterior and Posterior rami
Sympathetic Innervation: Pass into … nerves to supply organs
Splanchnic
Sympathetic Innervation to the Head and Neck: Presynaptic sympathetic axons from the CNS exit the spinal cord where?
T1 spinal nerve
Sympathetic Innervation to the Head and Neck: Pre-synaptic sympathetic axons ascend within what to synapse with what?
The sympathetic chain to synapse with the superior cervical sympathetic ganglion
Sympathetic Innervation to the Head and Neck: Post-synaptic sympathetic axons enter what nerves?
Internal and external carotid nerves
Sympathetic Innervation to the Head and Neck: Internal and External Carotid Nerves are carried to the organs of the head on the surface of what?
Branches of the internal and external carotid arteries
Sympathetic Innervation to the Head and Neck: What carries sympathetic axons into the orbit?
Opthalmic artery from the internal carotid
Parasympathetic Innervation: All parasympathetic axons leave the CNS via what nerves?
III
VII
IX
X
Parasympathetic Innervation: Ganglia in the head go to what regions? (3)
Eye
Lacrimal Gland
Salivary Gland
Parasympathetic Innervation: Ciliary Ganglion - Parasympathetic ganglion located where?
Bony orbit
Parasympathetic Innervation: Ciliary Ganglion - Parasympathetic innervation supplied by what?
Fibres of the oculomotor nerve
Oculomotor Nerve: Connects with the CNS where?
At the junction of the midbrain and pons
Oculomotor Nerve: Passes through what sinus?
Cavernous sinus
Oculomotor Nerve: Exits where?
Superior Orbital Fissure
Oculomotor Nerve: Supplies somatic motor to what?
Majority of the extraocular muscles
Oculomotor Nerve: Supplies presynaptic ganglion axons to what?
Ciliary ganglion
Eye Surface: The … does not cover the cornea of the eye
Conjunctiva
Eye Surface: Conjunctiva - What forms the deepest part of the eyelid?
The palpebral conjunctiva
Eye Surface: Conjunctiva definition
Thin mucous membrane that is reflected onto the sclera of the eyeball
Medical word for the eyeball
Bulbar conjunctiva
Eye Surface: Two layers
Conjunctiva
Fibrous layer
Eye Surface: Fibrous Layer Description
Outermost layer that consists of the sclera and cornea
Eye Surface: Fibrous Layer - Sclera provides attachment for what?
Extraocular muscles
Eye Surface: Fibrous Layer - Where is light refracted?
Cornea
Eye Surface: Fibrous Layer - 2 parts
Sclera
Cornea
Eye Surface: Fibrous Layer - Function of the sclera
Muscle attachment
Eye Surface: Uvea description
Vascular Middle Layer
Eye Surface: Uvea - 3 parts
Iris
Ciliary Body
Choroid
Eye Surface: Uvea - Iris description
Pigmented membrane with a central opening that adjusts in size in response to light
Eye Surface: Uvea - What is the central opening in the middle of the iris?
Pupil
Eye Surface: Uvea - Iris function
Regulates the amount of light that reaches the retina
Eye Surface: Uvea - Ciliary body functions (3)
Adapts the shape of the lens
Anchors the lens
Produces aqueous humor
Eye Surface: Uvea - Two parts to the Ciliary body
Ciliary muscle
Ciliary processes
Eye Surface: Uvea - Ciliary muscle consists of what?
Collection of smooth muscles that are attached to the lens of the eye by the ciliary processes
Eye Surface: Uvea - Choroid Description
Layer of connective tissue and blood vessels that provide nutrition and gas exchange to the outer layers of the retina
Eye Surface: Retina - Fundus description
The interior surface of the eye that is opposite the lens where light is focused
Eye Surface: Retina - The Fundus includes what structures? (5)
Retina
Optic disc
Macula
Fovea
Posterior pole
Eye Surface: Retina - Function
Light detecting component of the eye
Eye Surface: Retina - How many layers of cells?
10
Eye Surface: Retina - What are the 4 main layers?
Retinal Pigement Epithelium
Photoreceptors - Rods and Cones
Bipolar neurones
Ganglion neurones
Eye Surface: Retina - Retinal pigment epithelium function
Separates the choroid from the retina proper
Eye Surface: Retina - Optic Disk formed from what?
Axons of ganglion
Eye Surface: Retina - Optic Disc axons of ganglion cells form what?
Optic Nerve
Eye Surface: Retina - Optic Disc is the only point of what?
Entry or exit of blood vessels and axons of CN II
Eye Surface: Retina - What is not detected at the optic disc?
Light
Eye Surface: Retina - Macula definition
Centre of the retina
Eye Surface: Retina - Macula has a high density of what?
Cones
Eye Surface: Retina - Fovea description
Depression of 1.5mm diameter at the centre of the macula
Eye Surface: Retina - Fovea function
High acuity vision
Eye Surface: Retina - Where are the retinal veins and retinal arteries?
Anterior to the retina
Posterior Segment: Location
Behind the lens
Posterior Segment: Proportion of the eye
2/3
Posterior Segment: Contains the what?
Vitreous body
Posterior Segment: Vitreous humor description
Water-like substance
Posterior Segment: Common location for what?
Floaters - collections of proteins in the humor
Anterior Segment: Location
In front of the lens
Anterior Segment: What are the two chambers?
Anterior and Posterior Chamber
Circulation of Aqueous Humor: Ciliary Body produces what?
Aqueous Humor
Circulation of Aqueous Humor: Following circulation the humor circulates where?
Within the posterior chamber to nourish the lens
Circulation of Aqueous Humor: Humor passes to where following the posterior chamber?
Through the pupil into the anterior chamber to nourish the cornea on posterior aspect
Circulation of Aqueous Humor: Anterior aspect of the eye is nourished by what?
Tears
Circulation of Aqueous Humor: Humor is reabsorbed by what and where?
Scleral Venous Sinus at the Iridocorneal Angle
Circulation of Aqueous Humor: Alternate name for Scleral Venous Sinus
Canal of Schlemm
Cataract
Clouding of the lens
Arterial Supply: Eyeball receives arterial blood supply primarily from what?
Ophthalmic artery
Arterial Supply: Ophthalmic artery is a branch of what?
Internal carotid artery
Arterial Supply: Infraorbital artery supplies structures where?
Floor of the orbit
Arterial Supply: Infraorbital artery is a branch of what?
External carotid artery
Arterial Supply: Central artery supplies what?
Internal surface of the retina
Arterial Supply: What is the disadvantage of the central artery?
End artery - occlusion causes blindness
Arterial Supply: What supplies the choroid?
Three ciliary arteries
Arterial Supply: Central artery of the retina pierces what structure?
Optic nerve
Venous Drainage: Carried out by what veins?
Superior and Inferior Ophthalmic Veins
Venous Drainage: Veins drain into what?
Cavernous sinus
Venous Drainage: Veins drain into the cavernous sinus via what?
Superior orbital fissure
Venous Drainage: Orbit drains anteriorly into what?
Facial vein
Danger Triangle: Why is this clinically significant?
Retrograde infection from the nasal area to the brain due to venous communication via the ophthalmic veins between the facial vein and cavernous sinus
Visual Pathway: Light from the left visual field strikes what?
Nasal retina of the left eye and Temporal retina of the right eye
Visual Pathway: Light from the right visual field strikes what?
Nasal retina of the right eye and Temporal retina of the left eye
Visual Pathway: What crosses at the optic chiasma?
Nasal retina
Visual Pathway: Where is light processed?
On the opposite side visual cortex to the visual field
Complete interruption of the retinal branch artery or retinal vein has what impact?
Loss of area of the visual field due to ischaemia
Complete interruption of flow to the central artery or vein has what impact?
Monocular blindness