Flashcards
Orbits
Cards in this deck (200)
- 1What shape are the orbits?Pyramidal
- 2What is found in the space between functional structures of the orbits?Orbital fat
- 3What forms the superior wall (roof) of the orbits?1. Orbital part of frontal bone
2. Lesser wing of sphenoid (towards apex of orbit) - 4What occupies the fossa found anterolaterally in the orbital part of the frontal bone?Lacrimal gland (in lacrimal fossa)
- 5What forms the medial wall of the orbit?1. Mainly ethmoid bone
2. Frontal bone superiorly
3. Lacrimal bone anteriorly
4. Sphenoid bone posteriorly - 6What indents the medial wall of the orbit anteriorly?Fossa for lacrimal sac and lacrimal groove
- 7What forms the lateral wall of the orbit?1. Frontal part of zygomatic bone
2. Greater wing of sphenoid - 8What is the thickest part of the bones making up the orbit?Lateral wall
- 9What forms the floor of the orbit?1. Mainly maxilla
2. Partly by zygomatic
3. Some by palatine (posterior-most) - 10The floor of the orbit is the roof of what structure?Maxillary sinus
- 11What demarcates the boundary of the inferior wall from the lateral wall of the orbit posteriorly?Inferior orbital fissure
- 12What is found at the apex of the orbit?Orbital canal
- 13What skeletal structure is found just lateral to the orbital canal?Superior orbital fissure
- 14What lines the bones of the orbit?Periorbita
- 15What is the periorbita continuous with at the optic canal and superior orbital fissure?Periosteal layer of dura
- 16What is the periorbita continuous with at the orbital margins and inferior orbital fissure?Periosteum covering external surface of cranium (pericranium)
Also with orbital septa at the orbital margins - 17What is the periorbita continuous with at the extra-ocular muscles?Fascial sheaths
- 18What is the periorbita continuous with on the surface of the eyeball?Orbital fascia forming fascial sheaths of eyeball
- 19What ridges are found on either side of the fossa of the lacrimal sac?Anterior and posterior lacrimal crests
- 20What is the medical term for eyelids?Palpebrae
- 21What are the functions of the eyelids?1. Protect eye from injury and excessive light
2. Spread lacrimal fluid keeping cornea moist - 22What covers the eyelids externally?Thin skin
- 23What covers the eyelids internally?Palpebral conjunctiva (a transparent mucous membrane)
- 24What is the palpebral conjunctiva continuous with as it reflects?Bulbar conjunctiva (covering sclera of eyeball)
- 25What is found within the bulbar conjunctiva?Small blood vessels
- 26What is the bulbar conjunctiva adherent to centrally?Periphery of the cornea
- 27What is the name given to the deep recesses formed by the lines of reflection of the palpebral conjunctiva onto the eyeball?Superior and inferior conjunctival fornices
- 28What is the name of the space bound posteriorly by the bulbar conjunctiva and anteriorly by the palpebral conjunctiva?Conjunctival sac
- 29What is the purpose of the conjunctival sac?Enables the eyelids to move freely over the surface of the eyeball
- 30What is the name of the boundary between the sclera and the cornea?Corneoscleral junction
- 31What dense bands of connective tissue strengthen the superior and inferior eyelid (found just deep to the palpebral conjunctiva?Superior and inferior tarsi
- 32The insertion of what muscular fibres are found immediately deep to the external skin of the eyelid?Obicularis oculi
- 33What is found embedded in the superior and inferior tarsi?Tarsal glands
- 34What is the function of the tarsal glands?Secrete a lipid secretion that lubricates the edges of the eyelids preventing them from sticking together when they close
- 35What well-recognised event occurs when there is excessive lacrimal gland secretion?Crying
- 36What glands are associated with eyelashes? What type of gland are they?Ciliary glands
They are large sebaceous glands. - 37What is the alternative name for the lateral/medial angles of the eye?Lateral/medial canthi
- 38What is the name of the low reservoir of tears found at the median angle of the eye?Lacrimal lake
- 39What is the reddish modified skin found at the median angle of the eye?Lacrimal caruncle
- 40What name is given to the edge of skin lateral to the lacrimal caruncle that slightly overlaps the eyeball?Semilunar conjunctival fold
- 41What is the name of the 1. slight elevation of skin; and 2. its circular open, found on the superior and inferior eyelid towards its medial end?1. Lacrimal papilla
2. Lacrimal punctum - 42What connects the tarsi to the medial margin of the orbit?Medial palpebral ligament
- 43What attaches the tarsi to the lateral margin of the orbit?Lateral palpebral ligament
- 44What connects the tarsi to the superior and inferior margins of the orbit?Superior and inferior orbital septum
- 45What can the orbital septum be beneficial?1. Keeps orbital fat contained
2. Limit spread of infection to and from the orbit - 46What secretes lacrimal fluid?Lacrimal gland (in lacrimal fossa)
- 47Where do the excretory ducts of the lacrimal gland open into?Superior conjunctival fornix or superior conjunctival sac
- 48Describe the movement of lacrimal fluid when blinking?Eyeballs become dry, eyelids close in a lateral to medial direction pushing lacrimal fluid across eye inferomedially towards the lacrimal lake.
- 49How is lacrimal fluid drained from the eye?Via lacrimal puncta (in lacrimal papilla), which passes to lacrimal canaliculi and to the lacrimal sac?
- 50What is the lacrimal sac continuous with inferiorly?Nasolacrimal duct (conveys lacrimal fluid to nasal cavity to enter nasopharynx =swallowed)
- 51Where does the nasolacrimal duct open?Inferior meatus (inferior to inferior concha)
- 52What nervous system stimulates production of lacrimal fluid from the lacrimal gland?Parasympathetic
- 53What nerves convey the presynaptic parasympathetic secretomotor fibres to the lacrimal gland?1. Facial nerve (CN VII) by its greater petrosal nerve (branch)
2. Then by the nerve of the pterygoid canal - 54Where do presynaptic parasympathetic secretomotor fibres to the lacrimal gland synapse?Pterygopalatine ganglion
- 55Where do postsynaptic vasoconstrictive sympathetic fibres to the lacrimal gland originate?Superior cervical ganglion
- 56What nerves convey postsynaptic vasoconstrictive sympathetic fibres to the lacrimal gland?1. Internal carotid plexus
2. Then nerve of the pterygoid canal to transverse the pterygopalatine ganglion (do not synapse) - 57What nerves convey both postsynaptic para- and sympathetic fibres from the pterygopalatine ganglion to the lacrimal gland?1. Branches of zygomatic nerve (branch of maxillary nerve CN V 2)
2. Then by the lacrimal branch of the ophthalmic nerve CN V 1) where they enter the gland. - 58What is the average diameter of the eyeball?25mm
- 59How many layers are there to the eyeball proper?3
- 60What additional layer surrounds the eyeball proper?A connective tissue layer:
Posteriorly: Fascial sheath of the eyeball (bulbar fascia or Tenon capsule)
Anteriorly: Bulbar conjunctiva - 61What loose connective tissue layer (or potential space) is found between the fascial sheath of the eyeball and the outer coat of the eyeball proper? What is its function?Episcleral space
Facilitates movement of eyeball within facial sheath - 62What makes up the outer coat of the eyeball proper?Sclera and cornea
(fibrous layer) - 63What forms the middle coat of the eyeball proper?Choroid, ciliary body and iris
(vascular layer) - 64What forms the inner coat of the eyeball proper?Retina (optic and non visual parts)
(inner layer) - 65What provides the attachment for both extrinsic and intrinsic muscles of the eye?Sclera
- 66What proportion of the eyeball's surface does the sclera cover?5/6
- 67How does the cornea receive nourishment?Cornea is avascular:
1. Periphery capillary beds
2. Lacrimal fluid
3. Aqueous humour - 68What nerve supplies the cornea?Ophthalmic nerve CN V 1
- 69What is the name given to the angle formed by the intersecting curvatures of the sclera and cornea at the corneoscleral junction?Corneal limbus
- 70What is found within the corneal limbus?Limbal plexus:
numerous capillary loops involved in nourishing the avascular cornea - 71What is another name for the vascular layer (middle coat) of the eyeball proper?Uvea (uveal tract)
- 72What name is given to the finer, innermost capillary bed found adjacent to the retina?Capillary lamina of the choroid = choricocapillaries
- 73What vascular bed has the highest perfusion rate per gram of tissue in the body?Choroid plexus
- 74What is responsible for the red-eye seen in flash photography?Highly pigmented and vascularised choroid
- 75What is the choroid continuous with anteriorly?Ciliary body (+ iris)
- 76What does the ciliary body provide attachment for?Lens
- 77How is the smooth muscle of the ciliary body arranged?Circularly
- 78What are the folds found on the internal surface of the ciliary body?Ciliary processes
- 79What is the function of the ciliary processes?Secrete aqueous humour
- 80What space does aqueous humour occupy?Anterior segment of the eyeball (anterior chamber)
- 81Where is the anterior segment of the eyeball found?Interior of the eyeball, anterior to lens, suspensory ligaments and the ciliary body and posterior to the cornea
- 82What is the central aperture of the iris?Pupil
- 83What involuntary smooth muscle constricts the pupil?Sphincter pupillae
- 84What involuntary smooth muscle dilates the pupil?Dilator pupillae
- 85What nervous system innervates 1. sphincter pupillae; 2. dilator pupillae?1. Parasympathetic
2. Sympathetic - 86How are the fibres of 1. sphincter pupillae; 2. dilator pupillae, arranged?1. Circularly
2. Radially - 87How do the parasympathetic and sympathetic innervation of the pupillary muscles in response to changes in light differ in terms of reaction time?Sympathetic is slow to respond: may take 20 mins to adjust to darkened room.
Parasympathetic is instantaneous. - 88What name is given to abnormal sustained pupillary dilation?Mydriasis
- 89What are the two functional parts of the retina?1. Optic
2. Nonvisual - 90What are the two layers of the optic part of the retina?1. Neural layer
2. Pigmented layer - 91What is the property of the neural layer of the optic part of the retina?Light receptive
- 92What is the purpose of the pigmented layer of the optic part of the retina?Single layer of cells that reinforces choroid in reducing the scattering of light in the eyeball (light-absorbing properties)
- 93What is the anterior continuation of the pigmented layer of the optic part of the retina?Nonvisual part of retina
- 94What is the name given to the parts of the non visual retina extending over the 1. ciliary body; 2. iris?1. Ciliary part of retina
2. Iridial part of retina - 95What is the internal aspect of the posterior part of the eyeball where light is focused known as clinically?Fundus of the eyeball (ocular fundus)
- 96What name is given to the distinctive circular area found on the retina of the fundus?Optic disc (optic papilla)
- 97What occurs at the optic disk?Sensory fibres and vessels conveyed by the optic nerve (CN II) enter the eyeball and radiate out.
- 98Why is the optic disk referred to as the blind spot?Contains no photoreceptors and is insensitive to light
- 99What important spot is found just lateral to the optic disk?Macula lutea (macula)
- 100When would the yellow colour of the macula lutea be observed?When viewed under red-free light
- 101What is found at the macular lutea?Photoreceptor cones, specialised for acuity of vision
- 102What is the area of most acute vision? Where is it located?Fovea centralis
Found at the centre of the macula lutea - 103What is the central spot of the fovea centralise known as? What is not found here?Foveola
It does not have a capillary network deep to its retina (unlike rest of eye) - 104Approx what is the diameter of the fovea centralis?1.5 mm
- 105What demarcates the border between the optic and nonvisual parts of the retina?Ora serrata (at posterior border of ciliary body)
- 106What major artery/vein supply the majority of the retina?Central retinal artery/vein (branch of ophthalmic artery/vein)
- 107What supplies the rods and cones of the neural layer of the retina?Capillary lamina of the choroid (choriocapillaries)
- 108What are the refractive media of the eyeball?1. Cornea
2. Aqueous humour
3. Lens
4. Vitreous humour - 109What media of the eyeball refracts light to the greatest degree?Cornea
- 110What term is given to the orientation of the image focused on the light-sensitive retina?Inverted image
- 111What divides the anterior segment of the eyeball?Iris and pupil
- 112What are the two parts of the anterior segment of the eyeball?1. Anterior chamber of the eye
2. Posterior chamber of the eye - 113What bounds the anterior chamber of the eye anteriorly and posteriorly?Anteriorly: cornea
Posteriorly: iris and pupil - 114What bounds the posterior chamber of the eye anteriorly and posteriorly?Anteriorly: Iris/pupil
Posteriorly: Lens and ciliary body - 115Where is aqueous humour produced?Posterior chamber of the eye by the ciliary processes
- 116How does aqueous humour move from the posterior chamber to the anterior chamber of the eye?Through the pupil
- 117How does aqueous humour drain from the anterior chamber of the eye?Through trabecula at the iridocorneal angle into the scleral venous sinus
- 118What name is given to the junction between the iris and the cornea?Iridocorneal angle
- 119What do the scleral venous sinus drain immediately into?Limbal plexus
- 120To what two sets of tributaries do the limbal plexus drain into?1. Vorticose vein
2. Anterior ciliary veins - 121What determines intra-ocular pressure?The balance between production and outflow of aqueous humour
- 122What elastic structure envelops the lens?Capsule of the lens
- 123What anchors the lens?Zonular fibres (of the suspensory ligament) to the ciliary processes
- 124Contraction/relaxation of what allows the lens to change shape? What is the purpose of this?Ciliary muscle (in ciliary body)
Fine-tuning for focusing on near/far objects - 125Describe what occurs when focusing on distant objects (far vision)?There is an absence of nerve stimulation the ciliary muscles relax. Causing tension of the zonular fibres. The edges of the lens are stretched causing it to become thinner (less convex)
- 126Describe what happens when focusing on near objects (near vision)?Parasympathetic innervation (CN III) causes sphincter-like contraction of ciliary muscles. Relaxes zonular fibres
- 127What is the name given to the process of changing the shape of the lens for near vision?Accommodation
- 128What changes to the lens occur with age that limit a patient's ability to accommodate?Increased thickness of the lens
- 129What is the internal part of the eyeball found posterior to the lens?Posterior segment of the eyeball = postremal/ vitreous chamber
- 130What does the posterior segment of the eyeball contain?Vitreous body and vitreous humour
- 131What is the function of the vitreous humour?1. Transmits light
2. Hold retina in place
3. Supports lens - 132What are the 7 extra-ocular muscles?1. Levator palpebrae superioris
2. Superior rectus
3. Inferior rectus
4. Lateral rectus
5. Medial rectus
6. Superior oblique
7. Inferior oblique - 133What is the origin of levator palpebrae superioris?Lesser wing of the sphenoid bone, superior and anterior to the optic canal
- 134What is the insertion of levator palpebrae superioris?Superior tarsus and skin of superior eyelid
- 135What is the innervation of levator palpebrae superioris?Oculomotor nerve CN III.
The deep layer (superior tarsal muscle) is supplied by sympathetic fibres - 136What is the action of levator palpebrae superioris?Elevates superior eyelid (against gravity)
- 137What are the three axes in which rotation of the eye can occur around?1. Vertical
2. Transverse
3. Anteroposterior (A-P) - 138Describe the movements of the pupil with rotation around the vertical axis?Adduction (towards midline)
Abduction (away from midline) - 139Describe the movements of the pupil with rotation around the transverse axis?Elevation (superiorly)
Depression (inferiorly) - 140Describe the movements of the superior pole of the eyeball with rotation around the A-P axis?Medial rotation = intorsion
Lateral rotation = extorsion - 141What do the recti muscles of the eye arise from?Common tendinous ring
- 142What does the common tendinous ring surround?Surrounds optic canal (+optic nerve etc..) and part of superior orbital fissure (oculomotor nerve, abducent nerve etc..) at apex of orbit
- 143Where do the recti muscles of the eye insert?Onto the sclera, just posterior to the corneoscleral junction.
- 144What are the action of superior rectus?1. Elevation
2. Adduction
3. Intorsion - 145What is the action of inferior rectus?1. Depression
2. Adduction
3. Extorsion - 146What is the action of lateral rectus?Abduction
- 147What is the action of medial rectus?Adduction
- 148What is the action of superior oblique?1. Depression
2. Abduction
3. Intorsion - 149What is the action of inferior oblique?1. Elevation
2. Abduction
3. Extorsion - 150What is the origin of superior oblique?Body of the sphenoid bone
- 151What is the insertion of superior oblique?Passes through trochlea on superomedial wall of orbit to insert on sclera, deep to SR
- 152What is the origin of inferior oblique?Anterior part of medial floor of orbit
- 153What is the insertion of inferior oblique?Sclera, deep to lateral rectus
- 154What are the three main sources of innervation to the extrinsic muscles of the eye? What muscles do they innervate?Oculomotor: Levator palpebrae superioris, IO, SR, IR, MR
Trochlear (CN IV): SO
Abducent (CN VI): LR - 155In a clinical exam how might a doctor test a patients lateral rectus, followed by inferior and superior rectus?Ask patient to follow finger, direct patient laterally (testing LR and abducent nv), then in the lateral position move finger up and down to isolate IR and SR (and oculomotor nv)
- 156In a clinical exam how might a doctor test a patients medial rectus, followed by inferior and superior oblique?Ask patient to follow finger, direct patient medially (testing MR and oculomotor), then in medial position move finger up and down to isolate IO and SO (and oculomotor & trochlear nv)
- 157What supporting apparatus of the eye envelops the eyeball, extending from the conjunctival fornices to the optic nerve?Fascial sheath of eyeball
- 158How does the fascial sheath of the eyeball interact with the extrinsic muscles of the eye?Reflects onto them as they pierce the fascial sheath = become muscle sheath
- 159Why are the muscle sheaths of levator palpebrae superioris and superior rectus fused?So when the gaze is directed superiorly, the superior eyelid is further elevated out of the line of vision
- 160What arises from the muscle sheath of the medial and lateral recti muscles?Medial and lateral check ligaments
- 161Where do the medial and lateral ligaments attach? What is their function?Medial: lacrimal bone
Lateral: zygomatic bone
Limit abduction and adduction - 162What forms the suspensory ligament of the eyeball?Blending of medial and lateral check ligaments (of MR, LR) and fascia of inferior oblique to produce a hammock-like sling under the eyeball
- 163What retracts the lower eyelid when looking inferiorly?Check ligament of the muscle sheath of the inferior rectus
- 164What structures work together to resist the posterior pull on the eyeball produced by the rectus muscles?1. Check ligaments (medial, lateral (suspensory), inferior
2. Retrobulbar fat
3. Superior oblique
4. Inferior oblique - 165What name is given to the retraction of the eyeball into the orbit due to a reduction in retrobulbar fat as seen in starvation or some diseases?Enophthalmos
- 166What type of nerve fibres are conveyed in the optic nerve?Sensory fibres only
- 167What makes up the optic sheath?Intra-orbital extensions of cranial dura and arachnoid mater (+ subarachnoid space)
- 168What is the optic sheath continuous with anterior?Fascial sheath surrounding eyeball.
- 169What four nerves (+branches) pass through the superior orbital fissure?1. Oculomotor CN III
2. Trochlear CN IV
3. Abducent CN VI
4. Ophthalmic (CN V 1) - 170What are the branches of the CN III that arise in the orbit? What do they supply?Superior branch: SR, LP superioris
Inferior branch: IR, MR, IO, and supplies presynaptic parasympathetic fibres to the ciliary ganglion - 171What are the three branches of the ophthalmic nerve (CN V 1) that pass through the superior orbital fissure to supply orbit?1. Lacrimal nerve
2. Frontal nerve
3. Nasociliary nerve - 172What does the lacrimal nerve (branch of CN V1) supply?Sensory branches to conjunctiva and skin of superior eyelid, also carries secretomotor fibres from the zygomatic nerve CN V2
- 173Where does the lacrimal nerve branch off from the ophthalmic nerve (CN V1)?Lateral wall of cavernous sinus
- 174What are the two branches of the frontal nerve (branch of CN V1) what do they innervate?1. Supra-orbital
2. Supratrochlear
Supply sensory innervation to upper eyelid, scalp and forehead - 175What are the branches of the nasociliary nerve (branch of CN V1)?1. Infratrochlear nerve (terminal branch)
2. Anterior/posterior ethmoidal nerves\3. 3. Long ciliary nerves - 176What does the infratrochlear nerve innervate (terminal branch of nasociliary nerve)?Sensory innervation to eyelids, conjunctiva, skin of nose, lacrimal sac
- 177What do the anterior and posterior ethmoidal nerves innervate (branches of nasociliary nerve)?Mucous membrane of sphenoidal & ethmoidal sinuses; nasal cavities; dura mater of anterior cranial fossa
- 178What important neural structure is located between the optic nerve and the lateral rectus towards the apex of the orbit?Ciliary ganglion
- 179What are the three sources of nerve fibres received by the ciliary ganglion?1. Sensory fibres from nasociliary nerve (branch of CN V1)
2. Presynaptic parasympathetic fibres from oculomotor nv (CN III)
3. Postsynaptic sympathetic fibres from internal carotid plexus (transverse the ganglion) - 180What nerves arise from the ciliary ganglion?SShort ciliary nerves
- 181What nervous fibres are conveyed by the short ciliary nerves?1. Postsynaptic parasympathetic fibres from ciliary ganglion
2. Afferent (sensory fibres) of nasociliary nerve
3. Postsynaptic sympathetic fibres (that transversed ciliary ganglion) - 182What do the short ciliary nerves supply?Iris and cornea
- 183What do the long ciliary nerves convey?Nasociliary fibres:
1. Postsynaptic fibres
2. Sensory fibres - 184What do the long ciliary nerves supply?1. Dilator pupillae
2. Sensory to iris and cornea - 185What nerves pass through the common tendinous ring?1. Optic
2. Oculomotor (superior and inferior branches)
3. Nasociliary branch of ophthalmic nerve (CN V1)
4. Abducent nerve (CN VI) - 186What nerves pass superior to the common tendinous ring?1. Frontal nerve (branch of ophthalmic)
2. Lacrimal nerve (branch of ophthalmic)
3. Trochlear (CN IV) - 187Which nerve is responsible for directly conveying motor innervation to sphincter pupillae?Short ciliary nerves
- 188Branches of what artery supply the majority of the orbit?Ophthalmic (a branch of ICA)
- 189What other artery contributes to the supply of the orbital floor and adjacent structures?Infra orbital artery (branch of third part of maxillary artery = branch of ECA)
- 190What artery pierces the dural sheath of the optic nerve and runs within the nerve to reach the optic disc?Central retinal artery (branch of ophthalmic artery)
- 191What arteries supply the capillary lamina of the choroid?x6 short posterior ciliary arteries (from ophthalmic artery)
- 192What do the x2 long posterior ciliary arteries supply?Pass between sclera and choroid to anastomoses with anterior ciliary arteries to supply ciliary plexus
- 193Where do the anterior ciliary arteries arise from?Muscular branches (supplying recti) of ophthalmic artery
- 194What do the terminal branches of the central retinal artery supply?Internal aspect of the retina
- 195What two veins are responsible for the majority of venous drainage in the orbit?1. Superior ophthalmic vein
2. Inferior ophthalmic vein - 196Where do the superior and inferior ophthalmic veins largely drain into?Pass through superior orbital fissure to drain into cavernous sinus
- 197What other venous network does the inferior ophthalmic vein drain into?Pterygoid venous plexus
- 198How might the central retinal vein drain from the eye?Either directly into cavernous sinus, or by joining one of the ophthalmic veins
- 199What veins are largely responsible for draining the vascular layer of the eyeball? What do they tend to drain into?Vorticose veins
Drain into inferior ophthalmic veins - 200What venous structure drains the anterior chamber of the eyeball (aqueous humour)?Scleral venous sinus
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- Year 1 Anatomy & SF2 Flashcards on Orbits, created by Lou Clark on 02/01/2017.
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- Lou Clark
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