Anatomy Flashcards
shortest most direct path the optic nerve is along which wall
medial wall
which channels in the medial wall of the orbit facilitate the spread of infection from ethmoid sinus into orbit
emissary channels
___ wing of the ____ bone houses the optic canal
lesser wing of sphenoid
infraorbital hypoesthesia suggests impigement of which nerve
infraorbital nerve
what contains the infraorbital nerve
infraorbital groove
retrobulbar optic neuritis causes pain with eye movement because the ___ & ____ rectus muscles are adjacent to the annulus optic nerve sheath at the ____ _ ____
retrobulbar optic neuritis causes pain with eye movement because the superior & medial rectus muscles are adjacent to the annulus optic nerve sheath at the Annulus of Zinn
volume of bony orbit
30ml
Orbit is ____ shaped and the ___ ___ represents the stem
Orbit is __pear__ shaped and the optic nerve represents the stem
Orbitan entrance height and width in mm
height 35mm
width 45 mm
widest park of orbital apex is where
1 cm behind the anterior orbital margin
depth of orbit in mm
40-45mm
name the 7 bones that make up the bony orbit
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Maxillary
Frontal
Zygomatic
Ethmoid
Lacrima
Sphenoid (greater and lesser wings)
Palatine
Orbital roof formed of
Orbital plate of frontal bone
lesser wing of sphenoid bone
Where does the lacrimal gland reside
orbtial roof anterolaterally behind the zygomatic process of the frontal bone
Medial wall of orbit formed from
Frontal process of maxillary
lacrimal
orbital plate of ethmoid
lesser wing of sphenoid
Fossa for lacrimal sac is formed by
frontal process of maxillary bone and lacrimal bone
the lacrimal fossa is continuous with the ____ canal which extends into the ____ ______
the lacrimal fossa is continuous with the nasolacrimal canal which extends into the inferior meatus
most common site of fracture following blunt trauma
lamina papyracea
floor of orbit is also roof of ____ ____
floor of orbit is also roof of maxillary sinus
orbital bones of orbital floor
orbital plate of maxillary
palatine
orbital plate of zygomatic
Infraorbital nerve is ____ division of ______ nerve
Infraorbital nerve is maxillary division of trigeminal nerve
The floor of orbit slopes posterior to anterior how many degrees
20
Thickest and strongest orbital wall
lateral
Lateral obrital wall bones
Zygomatic and greater wing of sphenoid
Whitnall tubercle is elevation of which bone
zygomatic
where does the whitnall tubercle lie in relation to frontozygomatic suture
11mm below
Name 4 structures that attach to Whitnall ligament
Check ligament of LR
Lockwook suspensory ligament
lateral canthal tendon
lateral horn of levator aponeurosis
Which foramen is the entry point to optic canal
optic foramen
Optic foramen leads from _____ _____ ____ to _____ __ _____
Optic foramen leads from middle cranial fossa apex of orbit
Optic canal contains
Ophthalmic artery Optic nerve and sympathetic fibres from carotid plexus
Supraorbital nerve is extension of ____ nerve, branch of the ____ division of CN _
Supraorbital nerve is extension of frontal nerve, branch of the ophthalmic division of CN V
Supraorbital foramen transmits
supraorbital nerve
The nasolacrimal duct travels inferiorly from ______ ___ _____ into_______ ______
The nasolacrimal duct travels inferiorly from lacrimal sac fossa into inferior meatus
The lateral wall of each orbits forms and angle of ___ with the medial lane
45 degrees
Ciliary ganglion contains 3 roots which are ?
sensory
motor
sympathetic
Sensory root of ciliary ganglion arises from the _______ branch of CN _
Sensory root of ciliary ganglion arises from the nasocilairy branch of CN V1
The sensory root of the ciliary ganglion contains sensory fibres from which structures of the eye
cornea, iris and ciliary body
Motor root of ciliary ganglion arises from ______ division of CN _
Motor root of ciliary ganglion arises from inferior division of CN III
Motor root of ciliary ganglion carries ______ fibres from ________ nucleus
Motor root of ciliary ganglion carries preganglioninc parasympathetic fibres fibres from Edinger Westphal nucleus
Fibres of motor root synapse in the ciliary ganglion and postganglionic fibres carry parasympathetic axons to suppy the ____ ______
FIbres of motor root synapse in the ciliary ganglion and postganglionic fibres carry parasympathetic axons to supply the iris sphincter
Which fibres synapse in the ciliary ganglion
parasympathetic fibres
Where do short ciliary nerves arise from?
Ciliary ganglion
The long ciliary nerves arise from ____ branch of CN _
The long ciliary nerves arise from nasociliary branch of CN V1
Long ciliary nerves are sensory or motor?
sensory
Short ciliary nerve are sensory or motor?
both
which EOM originate from Annulus of Zinn
MR LR IR SR
Where does inferior oblique originate
depression on orbital floor near orbital rim
where does superior obliqu originate from
medial to optic froamen between annulis of Zinn and periorbita
MR inserts __ mm from limbus
MR inserts 5.5 mm from limbus
IR inserts __ mm from limbus
IR inserts 6.5 mm from limbus
LR inserts __ mm from limbus
LR inserts 6.9 mm from limbus
SR inserts __ mm from limbus
SR inserts 7.7 mm from limbus
LPS originates from
lesser wing of sphenoid
Superior orbital tendon gives rise to which muscles
superior rectus and portions of lateral and medial
Inferior orbtial tendon gives rise to which muscles
inferior recuts and portions of medial and lateral
which muscle does not orignate from orbital apex
inferior oblique
In EOM the ration of nerve fibres: muscle fibres is
1:3 - 1:5
In EOM the ration of nerve fibres: muscle fibres is high or low compared to skeletal
high
Fibres of EOM are mixture of ?
slow tonic fibres and fast twitch type fibres
Slow tonic fibres are useful for ____ _____ movements
smooth pursuit
Fast twitch fibres are useful for ___ ____ movements
rapid saccading
slow tonic type fibres have __ ____ nerve endings
en grappe
fast twitch fibres have __ ____ nerve endings
en plaque
Blood suppy of EOM
Anterior ciliary arteries ( branc of ophthlamic artery)
Hoe is blood drained in the eye
vortex veins
Which parts of the eye do vortex veins drain
choroid, ciliary body and iris
muscles (2) responsible of elevation of upper eyelid
levator palpebrae superioirs and Muller
Name the layers of the eyelid from skin inwards
Skin
Orbicularis
Orbital septum
Orbital fat
muscles of retraction - LPS /Muller
tarsus
conj
What are the 3 parts of the orbicularis muscle
orbital preseptal and pretarsal
___ punctum is located more medially
upper
name the modified sebaceous glands in the eyelid margin
glands of zeis
what are the apocrine sweat glands in the lid margin
glands of Moll
name 2 accessory lacrimal glands and what they secrete
Krausse and Wolfring, aqueous
WHat do goblet cells secrete
mucus
what do Meibomian glands secrete
oil
CN _ innvervates orbicularis oculi
CN VII
Which part of the orbicularis oculi is under only voluntary control
orbital
LPS orginates from ?
lesser wing of sphenoid
Innervation of LPS
CN III
Innervation of Mullers
sympathetic nervous sysstem
conjuntiva is _____ _____ _______ epithelium
conjuntiva is non kratinized stratified squamous epithelium
Eyelid vasculature is an anastamosis of ____ & _____ carotid arteries
external and internal
Facial system blood supply arises from
external carotid artery
orbital sysmte blood supply orignates from
internal carotid artery
Name the 2 groups of lymphatics in the eyelids
medial and lateral groups
Medial lymphatic vessels drain into
submandibular lymph nodes
Lateral lymphatic vessels drain into
superficial preauricular lymph nodes
Where is the lacrimal gland located
shallow depression in the orbital part of the frontal bone
What are the 2 lobes of the lacrimal gland
palpebral and orbital
Which lobe of the lacrimal gland is bigger
orbital
What type of gland is the lacrimal gland
exocrine
what are the 2 cell types of the lacrimal gland
glandular epithelial which line the lumen
myoepithelial which surround the parenchyma and covered by a basement membrae
Lacrimal secretions contain immunoglobulin _?
immunoglobulin A
Blood supply of lacrimal gland
Lacrimal arter - branch of ophthalmic artery
Accessory lacrimal glands of Krause and WOlfring account for approx __ % of total lacrimal secretory mass
10%
diameted of lacrimal puncta
0.3mm
Distance of inferior punctum from inner canthus
6.5mm
distance of superior punctume to inner canthus
6mm
Persistent membrane over the ___ _ ___ is associated with tearing and discharge in NLDO
Persistent membrane over the valve of Hasner is associated with tearing and discharge in NLDO
How are tears driven down the canalicular system with blinking
fibres of the tarsal orbic surround the canalicular system and lacrimal sac
What are the 3 geographical zones of the conjunctiva
Palpebral (tarsal)
Forniceal
Bulbar
Bulbar conj fuses with ____ as it inserts into limbus
Tenons capsule
Blood supply of bulbar conj
anterioir ciliary artery
Blood supply of palebral conj
marginal arcades of eyelids
Innervation of conj
CN V
conj consists of _______ _____ ____ epithelium
conj consists of non keratnized stratified squamous epithelium
Thickness of conjunctival epithelium
2-5 cells
Basal cells of conj epithelium are
cuboidal
The tenon capsule fuses posteriorly with
optic nerve shealth
tenon capsule fuses anteriorly with
intermuscular seputm which is 3mm behind the limbus
where is the tenon capsule the thickest
equator of the blobe
Muscles penetrate the tenon capsule __ mm posterior to their insertions
10mm
medial periocular tissue drains into which lymphnodes?
submandibular
lateral periocular tissue drains into which lymphnodes?
superficial periauricular
