ORBIT Flashcards
Shape of the orbit
pyramidal
Each orbit is a——-sided—— with apex directed—- at the—— and base directed—-,represented by the——
four
pyramid
behind
optic canal
forward
orbital margin
The medial walls of two orbits are—— to each other but the lateral walls are——- to each other
parallel
set at right angle
The long axis of each orbit (——axis) passes—— and——-
orbital
backwards
medially
distance between the 2 medial walls of the orbit is——
2.5cm
optic fiber is myelinated or unmyelinated?
Myelinated
Thinnest and thickest walls of the orbit are?
Medial
Lateral
Medial wall of the orbit is formed by???
Frontal process of maxilla.
- Lacrimal process of maxilla.
- Orbital plate of ethmoid
- Body of sphenoid.
Lateral wall of the orbit is formed by???
Orbital surface of the zygomatic bone in front
-Orbital surface of greater wing of sphenoid behind.
Floor of the orbit is formed by???
Orbital surface of the body of maxilla
- Orbital surface of the zygomatic bone, anterolaterally.
- Orbital process of the palatine bone, posteromedially.
Roof of the orbit is formed by???
Orbital plate of the frontal bone in front
-Lesser wing of the sphenoid behind.
List two features of Medial wall of the orbit
Lacrimal fossa
Anterior and posterior ethmoidal foramina
Lacrimal fossa Is bounded in front by the—— of —- and behind by the——- of the—- bone.
anterior lacrimal crest
maxilla
posterior lacrimal crest
lacrimal
The lacrimal fossa communicates with the nasal cavity through———.
nasolacrimal canal
The lacrimal fossa and nasolacrimal canal contain—- and——, respectively.
lacrimal sac
nasolacrimal duct
Anterior and posterior ethmoidal foramina lie at the———
junction between medial wall and the roof of the orbit.
List the two features of the Lateral wall of the orbit
Zygomatic foramen
Whitnall’s tubercle
—- and —- can pass through the Zygomatic foramen
zygomaticofacial and zygomaticotemporal nerves.
Whitnall’s tubercle is a—— just behind the ——-and slightly—— the———
small bony tubercle
lateral orbital margin
below
frontozygomatic suture.
List the two features of the Floor of the orbit
Infraorbital groove and canal
Small rough impression in anteromedial angle for origin of inferior oblique muscle.
Route that leads to the Infraorbital foramen.
Originating from the ——the ——is the—— part of the IOC/G. It is followed by the —-which is covered by the—— and terminates at the infraorbital foramen
inferior orbital fissure
infraorbital groove
posterior
infraorbital canal
orbital floor
Roof Presents three features. List them and which part of the roof they can be found
Fossa for lacrimal gland in the anterolateral part
Trochlear notch or spine at the anteromedial angle
Optic canal at the extreme posterior part of the roof.
The trochlea of——muscle is a—— structure in the eye
-The—— of the ——muscle passes through it.
superior oblique
pulley-like
tendon
superior oblique
The apex of the orbit Lies at the—- end of the orbit and is formed by——
-More precisely it is formed by the—— between—— and——
posterior
sphenoid
centre of the bony bridge
optic canal
superior orbital fissure.
Base of the orbit is Open and—in shape
quadrangular
Supraorbital margin formed by the—— bone and presents a notch called the—— notch or foramen at the junction of———
frontal
supraorbital
its lateral two-third and medial one-third
Infraorbital margin of the orbit is formed by the—- bone—- and—-bone ——
-it is continuous with—— crest___
zygomatic; laterally
maxilla; medially
anteriorlacrimal
medially
——-orbital margin is ill-defined
Medial orbital margin
Medial orbital margin is formed by the——- bone—— and—— of the ——process of—— ——
frontal; above
lacrimal crest
frontal
maxilla
below
Lateral orbital margin is formed by ——- above and—— below
zygomatic process of the frontal bone
frontal process of the zygomatic bone
The margins of the orbit are readily palpable in vivo.
T/F
T
The orbital margins provide a fair bony protection to the eye except at the——- margin.
lateral
Protective eye guards don’t permit good peripheral vision..
T/F
F
RELATIONS OF ORBIT -Above ——-and——— -Lateral ——-and ——-behind. -Below ——— -Medial ———-
Anterior cranial fossa; frontal air sinus (usually).
Temporal fossa in front; middle cranial fossa
Maxillary air sinus
Ethmoidal air sinuses.
ORBITAL FASCIA aka——-
- lines the ——-of the orbit
- forms a——- -shaped fascial sheath that———
PERIORBITA
bony boundaries
funnel
encloses the orbital contents
ORBITAL FASCIA is loosely attached to the bones.
T/F
T
ORBITAL FASCIA can be easily stripped off especially from——- and ——-of the orbit.
roof
medial wall of
At the—- and superior orbital fissure, periorbita becomes continuous with the periosteum lining the—— of the skull (called the ——).
optic canal
interior
endocranium
At the——- fissure and——, periorbita becomes continuous with the periosteum covering the——- surface of the skull (called the ——)
infraorbital
orbital margins
external; periosteum
——nerve and vessels and—— nerve lie outside the orbital periosteum, hence—— in the contents of the orbit.
Infraorbital
zygomatic
not included
EXTRAOCULAR MUSCLES are classified into two groups:—- and___.
voluntary ;involuntary
There are ——-VOLUNTARY extraocular MUSCLES.—— muscles move the eyeball and—- muscle moves the——
seven
six
one
upper eyelid.
List the voluntary extraocular muscles moving the eyeball
Four recti muscles
- Superior rectus
- Inferior rectus
- Medial rectus
- Lateral rectus.
Two oblique muscles
- Superior oblique
- Inferior oblique.
The voluntary extraocular muscle which moves the upper eyelid is called———
levator palpebrae superioris
There are ——-INVOLUNTARY extraocular MUSCLES
three
List the INVOLUNTARY extraocular MUSCLES
Orbitalis
Superior tarsal
Inferior tarsal
Another name for superior tarsal is ——-
Muller’s muscle
All the recti muscles of the eye arise from the——
corresponding margins of the common tendinous ring.
——-rectus arises by two heads.
lateral
The common tendinous ring encloses the optic canal and—— part of the——-
middle
superior orbital fissure.
common tendinous ring is attached medially to —— of the orbit and laterally to a small tubercle (tubercle of ——) on the—— border of ——
apex
Zinn
lower
superior orbital fissure.
All the recti muscles of the eye are inserted into—— little posterior to the——- in front of the——- of the eyeball.
sclera
limbus
equator
Limbus of the eyeball is also know as——?
corneoscleral junction
Average distance of the recti muscles from limbus is: Medial rectus -mm Inferior rectus— mm Lateral rectus—- mm Superior rectus —-mm
5mm
6
7
8
Superior oblique
Origin:
-from——— that’s superomedial to the——
Insertion
- into——;—— the equator
- between—- and—- rectus
body of Sphenoid
optic canal
sclera; behind
superior; lateral
Inferior oblique
Origin:
-from rough impression in—- part of the—— of the orbital Cavity,—— to lacrimal groove
Insertion
-into—- ;—- the equator
anteromedial; floor; lateral
sclera; behind