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111 Cards in this Set

  • Front
  • Back
Bones of the Orbit
Lesser wing of sphenoid
Superior orbital fissure
Greater wing of sphenoid
Frontal bone
Optic Canal
Ethmoidal foramina
Ethmoid Bone
The shape of the orbit is almost _____
pyramidal
Medial walls of the orbit are ____. Lateral walls are __________.
parallel; at right angles
The orbit is comprised of all or part of ____ bones and lined with_________which forms a funnel shaped fascial sheath that encloses the orbital contents.
Seven; periorbita (orbital periosteum)
Orbital margin of the orbit
Frontal bone
Maxilla
Zygomatic bone
Superior wall or roof
Frontal bone (orbital plate)
Lesser wing of the sphenoid bone
(Posterior part)
Medial wall of orbit
a. Ethmoid - lamina papyracea
b. Frontal bone
c. Lacrimal bone
d. Sphenoid bone
Inferior wall - or Floor; separated from lateral wall by the inferior orbital fissure
a. Maxilla - orbital surface
b. Zygomatic bone
c. Palatine bone – (orbital process)
Lateral Wall of orbit
a. Zygomatic bone - frontal process
b. Sphenoid bone - greater wing
Orbital margin fractures
fractures at the suture
Blowout fractures
medial and inferior walls are thin and may fracture while the margin remains intact
Superior wall is ________ but still thin and can be penetrated by sharp objects. Problematic because it is directly related to the _______.
stronger; frontal lobe
Openings into the Orbit
Superior orbital fissure
Inferior orbital fissure
Optic Canal
Optic Canal
- transmits optic nerve (CN II), ophthalmic artery
Superior Orbital Fissure
- transmits oculomotor nerve (CN III), trochlear nerve (CN IV), ophthalmic division of trigeminal nerve (CN V1), abducens nerve (CN VI) and superior ophthalmic vein
Inferior orbital fissure
- transmits maxillary division of the trigeminal nerve (CN V2) and the infraorbital artery and vein
Soft tissues of the orbit are called
the eyelids
Soft tissues of the orbit include
Skin
Tela subcutanea
Orbicularis oculi muscle
Fibrous layer (for upper lid)
Conjunctiva
Muscles responsible for opening and closing palpebral fissure
SKin of the orbit
thin, delicate and transparent
Tela Subcutanea of the orbit
loose, allows accumulation of fluid (edema or “black eye”)
Orbicularis oculi muscle
1. Closes palpebral fissure
2. Muscle of facial expression
Muscle of facial expression of the orbit
a. Palpebral part
b. Orbital part
c. Lacrimal part
Fibrous Layer (described for upper lid) of the orbit
1. Orbital septum
2. Aponeurosis of levator palpebrae superioris muscle
3. Superior tarsal muscle
4. Tarsal plate
Orbital septum
continuous with the periorbita inside the orbit and the periosteum covering frontal bone
Part of the fibrous layer of the orbit
Aponeurosis of levator palpebrae superioris muscle
part of the fibrous layer of the orbit
Superior tarsal muscle
smooth muscle innervated by sympathetic n.s.
part of the fibrous layer of the orbit
What is the major support for the eyelid?
Tarsal plate
Tarsal plate
a. major support for the eyelid
b. plate of dense connective tissue anchored to the anterior lacrimal crest medially and the orbital tubercle of zygomatic bone laterally
c. embedded within it is the tarsal gland (responsible for increasing the viscosity of tears and decreasing their evaporation
Part of the fibrous part of the orbit
Conjunctiva of the eye
1. Palpebral conjunctiva- continuous with bulbar conjunctiva at superior and inferior conjunctival fornices)
2. Orbital (bulbar) conjunctiva
3. Conjunctival fornix - junction of palpebral and orbital (bulbar) conjunctivae
Palpebral conjunctiva
continuous with bulbar conjunctiva at superior and inferior conjunctival fornices)
Conjunctival fornix
junction of palpebral and orbital (bulbar) conjunctivae
Conjunctivitis
conjunctiva is colorless except when vessels are dialated/congested; conjunctivitis results from bacterial or viral infections or severe allergies
Subconjunctival hemorrhage
can occur due to injury/inflammation
Muscles responsible for opening palpebral fissure.
a. Levator palpebrae superioris - comprised of skeletal muscle; innervated by Cranial Nerve III
b. Superior tarsal muscle - comprised of smooth muscle; innervated by sympathetic nervous system; see section VIII - Smooth Muscle of the Orbit
Levator palpebrae superioris
comprised of skeletal muscle; innervated by Cranial Nerve III
Superior tarsal muscle
comprised of smooth muscle; innervated by sympathetic nervous system; see section VIII - Smooth Muscle of the Orbit
Closure of the eyelid is done by _____ ____.
orbicularis oculi - comprised of skeletal muscle; innervated by Cranial Nerve VII
Orbicularis oculi is innervted by
Cranial nerve VII
Lacrimal Apparatus includes
A. Lacrimal gland
B. Lacrimal Puncta
C. Lacrimal Canaliculi
D. Lacrimal Sac
E. Nasolacrimal Duct
F. Lacrimal Gland Secretion
Lacrimal Gland
1. Located in lateral aspect of the orbit posterior to the orbital septum
2. Curves around lateral edge of aponeurosis of levator palpebrae superioris muscle
3. Tears are secreted into the superior fornix of conjunctival sac and washed across the eyeball to the lacrimal lake to then enter:
B. Lacrimal Puncta
C. Lacrimal Canaliculi
D. Lacrimal Sac
E. Nasolacrimal duct
Tears are secreted into the ________ of conjunctival sac and washed across the eyeball to the lacrimal lake to then enter:
superior fornix


B. Lacrimal Puncta
C. Lacrimal Canaliculi
D. Lacrimal Sac
E. Nasolacrimal duct
Nasolacrimal duct
Connects lacrimal sac to the inferior meatus
Lacrimal Gland Secretion is a result of stimulation of _______.
postganglionic parasympathetic fibers in lacrimal n.

Cell bodies: pterygopalatine ganglion
Preganglionic parasympathetic fibers have their cell bodies in the superior salivatory nucleus and leave the brainstem in the facial nerve (CN VII).
Cell bodies of Lacrimal gland secretion are located in
pterygopalatine ganglion
Preganglionic parasympathetic fibers have their cell bodies in the________ and leave the brainstem in the ______.
superior salivatory nucleus; facial nerve (CN VII
Superior Oblique muscle is innervated by the ______ and the cell bodies are in the ____
the Trochlear N; Trochlear nucleus
The origin of the superior oblique muscle is
the body of the sphenoid
The Lateral Rectus muscle is innervated by the ___ and the cell bodies are in the ____
Abducens N; Abducens nuclues
The levator palpebrae superioris is innervated by the _____ and the cell bodies are located in the _____.
Oculomotor N; oculomotor nucleus
The inferior rectus, medial rectus, superior rectus, levator palpebrae superioris, and inferior oblique muscles are all innervated by the _____ and the cell bodies are in the _____
Oculomotor N; oculomotor nucleus
The origin of the levator palpebrae superioris muscle is the
lesser wing of sphenoid
The origin of the inferior rectus muscle, medial rectus muscle, and superior rectus muscle is the
common tendinous ring
The origin of the inferior oblique muscle is the
anterior floor of orbit
Medial rectus muscle functions only in
adduction
Lateral rectus muscle functions only in
abduction
Primary and secondary action of superior rectus m.
P-elevation
S-adduction
Primary and secondary action of the inferior rectus
p-depression
s-adduction
Inferior oblique primary and secondary action
p-elevation
s-abduction
Superior oblique muscle primary and secondary action
p-depression
s-abduction
Testing of Extraocular Muscles
1. Each muscle is examined at its position of greatest efficiency
2. The medial and lateral recti can be tested easily for their single actions
3. The other four muscles must be specially positioned so that the muscle being tested is the only muscle capable of performing the required primary action.
a. Eye abducted - superior rectus elevates, inferior rectus depresses
b. Eye adducted - inferior oblique elevates, superior oblique depresses
Eye abducted (what muscles)?
superior rectus elevates, inferior rectus depresses
Eye adducted (what muscles)?
inferior oblique elevates, superior oblique depresses
Arterial supply to the orbit and eyeball includes
branch of internal carotid
branches of ophthalmic artery
1. Posterior ethmoidal
2. Anterior ethmoidal
3. Dorsal nasal
4. Supratrochlear
5. Supraorbital
6. Central artery of the retina - an end artery
7. Ciliary arteries - long and short posterior ciliary arteries
8. Lacrimal
9. Palpebral arteries


infraorbital A.
branches of Ophthalmic A that supply orbit and eyeball
1. Posterior ethmoidal
2. Anterior ethmoidal
3. Dorsal nasal
4. Supratrochlear
5. Supraorbital
6. Central artery of the retina - an end artery
7. Ciliary arteries - long and short posterior ciliary arteries
8. Lacrimal
9. Palpebral arteries-to supply the upper and lower lids
Veins of the orbit communicate with the dural venous sinuses (via the cavernous sinus), with the _____, and with the veins of the face via the _____
pterygoid plexus; angular vein
Veins of the orbit
1. Supraorbital vein
2. Infraorbital vein
3. Superior ophthalmic vein
4. Inferior ophthalmic vein
Nerves of the orbit
A. Optic (CN II)
B. Oculomotor (CN III)
1. Superior Division: levator palpebrae superioris, superior rectus
2. Inferior Division: medial rectus, inferior oblique and inferior rectus
C. Trochlear (CN IV)
D. Ophthalmic - V1 (sensory)
1. Frontal nerve
a. supraorbital
b. supratrochlear
2. Nasociliary nerve
3. Anterior ethmoid
4. Infratrochlear
5. Long ciliary
6. Short ciliary
E. Abducens (CN VI)
What muscles does the superior division of the oculomotor N innervate?
levator palpebrae superioris, superior rectus
What muscles does the inferior division of the oculomotor N innervate?
medial rectus, inferior oblique and inferior rectus
The three-layered sphere of the eyeball contain what three structures?
Fibrous coat (sclera and cornea)
Vascular coat (choroid, ciliary body, and iris)
Retina
The fibrous coat of the eyeball contains
a. Sclera - opaque posterior 5/6; provides shape, resistance, attachment for extraocular muscles and intrinsic muscles of the eye; “white of the eye”
b. Cornea - transparent anterior 1/6
Sclera is located in what part of the fibrous coat of the eyeball
opaque posterior 5/6; provides shape, resistance, attachment for extraocular muscles and intrinsic muscles of the eye; “white of the eye”

Part of the fibrous coat of the eyeball
Cornea is located in what part of the fibrous coat of the eyeball
transparent anterior 1/6

part of fibrous coat of eyeball
Vascular coat(uvea) contains
a. Choroid-between the slera and retina; firmly attached to retina and engorged with blood
b. Ciliary body - suspensory mechanism for lens, ciliary muscle controls shape of lens and thus, focus; ciliary processes secrete aqueous humor
c. Iris - muscular diaphragm to control light entrance; central aperature is the pupil
Choroid
between the slera and retina; firmly attached to retina and engorged with blood

part of vascular coat
Ciliary body
suspensory mechanism for lens, ciliary muscle controls shape of lens and thus, focus; ciliary processes secrete aqueous humor

vascular coat of eyeball
iris
muscular diaphragm to control light entrance; central aperature is the pupil

part of vascular coat of eyeball
Retina
a. inner layer
b. two parts:
1 optic: light sensitive; terminates along ora serrata
2. non-visual: fundus at posterior part of the eyeball; optic disc –sensory fibers and vessels conveyed by optic nerve enter ; insensitive to light
Refractive media of the eyeball includes
cornea
aqueuous humor
lens
vitreous body
Cornea
- transparent due to regular arrangement of collagen fibers and dehydrated state ; sensitive to touch; avascular, nourished by the aqueous humor and lacrimal fluid
Aqueous humor
made by ciliary processes; provides nutrients to the cornea and lens ; drains to the scleral venous sinus
lens
a. posterior to iris and anterior to vitreous humor/body
b. transparent, biconvex
c. elastic capsule anchored by zonular fibers to ciliary body and encircled by ciliary processes; contraction of smooth muscle in the ciliary body reduces tension on lens and it rounds up for near vision (accommodation)
Vitreous body
transmits light and holds retina in place; supports lens
Corneal abrasions/lacerations
foreign objects produce corneal abrasions
Glaucoma
a. drainage of aqueous humor thru sclera venous sinus is decreased; pressure builds in anterior and posterior chambers
b. can lead to blindness if pressure isn’t reduced.
Cataracts
loss of transparency in lens; results in areas of opaqueness
Hemmorhage into the anterior chamber
result of blunt force trauma to eye
Retinoblastoma
a. rare childhood cancer
b. can be unilateral or bilateral
c. most common sign: visible whiteness of normally black pupil in flash photography
d. Prototype of cancer with a genetic component: RB1 gene on Chromosome 13q.
Ciliary muscle
1. Action: narrows diameter of the ring formed by the ciliary body, releasing tension on the zonular fibers which, in turn, increases the curvature of the lens for near vision (accommodation).
2. Innervation: parasympathetic
3. Preganglionic nerves: nucleus of Edinger-Westphal, travel with the oculomotor nerve (III) to the ciliary ganglion
4. Ganglion: ciliary ganglion (comprised of cell bodies of parasympathetic postganglionic neurons which innervate the ciliary muscle and sphincter pupillae muscle)
5. Postganglionic nerves: short ciliary nerves
Action of ciliary muscle
narrows diameter of the ring formed by the ciliary body, releasing tension on the zonular fibers which, in turn, increases the curvature of the lens for near vision (accommodation).
Innervation of ciliary muscle
parasympathetic
Ciliary muscle preganglionic nerves
nucleus of Edinger-Westphal, travel with the oculomotor nerve (III) to the ciliary ganglion
Ciliary muscle ganglion
:ciliary ganglion (comprised of cell bodies of parasympathetic postganglionic neurons which innervate the ciliary muscle and sphincter pupillae muscle)
Ciliary muscle postganglionic nerves
short ciliary nerves
Sphincter pupillae muscle
1. Action: constricts the pupil
2. Innervation: parasympathetic
3. Preganglionic nerves: nucleus of Edinger-Westphal, travel with the oculomotor nerve (III) to the ciliary ganglion
4. Ganglion: ciliary ganglion (comprised of cell bodies of parasympathetic postganglionic neurons which innervate the ciliary muscle and sphincter pupillae muscle)
5. Postganglionic nerves: short ciliary nerves
Action of sphincter pupillae muscle
constricts the pupil
Innervation of sphincter pupillae muscle
parasympathetic
Preganglionic nerves of Sphincter pupillae m.
nucleus of Edinger-Westphal, travel with the oculomotor nerve (III) to the ciliary ganglion
Ganglion of sphincter pupillae m.
ciliary ganglion (comprised of cell bodies of parasympathetic postganglionic neurons which innervate the ciliary muscle and sphincter pupillae muscle)
Sphincter pupillae m. postganglionic nerves
short ciliary nerves
Dilator pupillae muscle
1. Action: enlarges the pupil
2. Innervation: sympathetic
3. Preganglionic nerves: intermediolateral cell column of upper thoracic levels
4. Ganglion: superior cervical ganglion
5. Postganglionic nerves: pass through the ciliary ganglion (without synapsing) and travel to the eye via the short ciliary nerves
Note: The superior tarsal muscle in the upper eyelid is also innervated by sympathetic nerves.
Action of dilator pupillae muscle
enlarges the pupil
Innervation of dilator pupillae muscle
sympathetic
Preganglionic nerves of dilator pupillae m.
intermediolateral cell column of upper thoracic levels
Ganglion of dilator pupillae m.
superior cervical ganglion
Postganglionic nerves of dilator pupillae m.
pass through the ciliary ganglion (without synapsing) and travel to the eye via the short ciliary nerves
Note: The superior tarsal muscle in the upper eyelid is also innervated by sympathetic nerves.
The ciliary ganglion will have sensory fibers from nasociliary branches (V1), postganglionic sympathetic fibers from the ____, and preganglionic parasympathetic fibers from the ____. ONLY THE PREGANGLIONIC PARASYMPATHETIC FIBERS SYNAPSE IN THE CILIARY GANGLION.
carotid plexus; oculomotor nerve
Pupillary Light Reflex
1. Light enters one eye and both pupils constrict because each retina sends fibers to the optic tract on both sides of the eye
2. One of the first signs of compression of the ophthalmic nerve is ipsilateral slowness of the papillary response to light
Horner Syndrome
interruption of the cervical sympathetic trunk resulting in absence of sympathetic functions on the ipsilateral side of the head.
Signs include:
-constriction of the pupil
-ptosis
-redness of skin and increased temperature of skin
-absence of sweating
What part of the orbit allows accumulation of fluid (edema or 'black eye')
tela subcutanea
what is the major support for the eyelid?
tarsal plate