Orbit Flashcards
What are the 7 bones of the orbit
SFLMEPZ
- Sphenoid
- Frontal
- Lacrimal
- Maxillary
- Ethmoid
- Palatine
- Zygomatic
What is a blow out fracture
Floor of the orbit is broken and the globe recedes inward, usually to blunt/penetrating trauma
What is the orbital septum…where is it located and what is its significance
A fibrous membrane that becomes continuous with the periosteum of the orbital margins. It is crucial in preventing the spread of infection into the orbit.
The nasolacrimal sac conveys lacrimal fluid from the _____ to the _______
lacrimal sac to the inferior nasal meatus
What is the origin, insertion, and innervation of the levator palpebrae superioris
Origin: lesser wing of sphenoid
Insertion: Superior tarsus and skin of upper eyelid
Innervation: Superior division of CN III
What is the primary action of the levator palpebrae superioris
Elevates upper lid
What is the origin, insertion, and innervation of the superior rectus
Origin: Common tendinous ring.
Insertion: Antero superior half of eye
Innervation: Superior division of CN III
What is the primary, secondary, and tertiary action of the superior rectus
Primary: Elevation
Secondary: Intorsion
Tertiary: Adduction
What is the origin, insertion, and innervation of inferior rectus
Origin: Common tendinous ring
Insertion: Antero inferior half of eye
Innervation: Inferior division of CN III
What is the primary, secondary, and tertiary action of inferior rectus
Primary: Depression
Secondary: Extorsion
Tertiary: Adduction
What is the origin, insertion, and innervation of medial rectus
Origin: common tendinous ring
Insertion: Anterio medial half of eye
Innervation: Inferior division of CN III
What is the primary action of medial rectus
adduction
What is the origin, insertion, and innervation of lateral rectus
Origin: Common tendinous ring
Insertion: antero lateral half of eye
Innervation: CN VI (abducens)
What is the action of the lateral rectus
abduction
What is the origin, insertion, and innervation of superior oblique
Origin: Body of sphenoid
Insertion; sclera deep to superior rectus
Innervation: CN 4 (trochlear)
What is the primary, secondary and tertiary action of the superior oblique
Primary: Intorsion
Secondary: Depression
Tertiary: Abduction
What is the origin, insertion, and innervation of the inferior oblique
Origin: Antero medial floor of orbit
Insertion; sclera deep to lateral rectus
Innervation: Inferior division of CN III
What is the primary, secondary and tertiary action of inferior oblique
Primary: Extorsion
Secondary: Elevation
Teriary: Abduction
SO, IO, and Lateral rectus hold the eye ____
abducted
H test for the SO and IO muscles:
- Patient directs eye ______
- Patient looks ________ to test the IO
- Patient looks _______ to test the SO
- medially
- UP
- Down
Superior, inferior, and medial recti hold the muscles
adducted
H test for the SR and IR muscles:
- Patient directs eye in question _______
- Patient looks ____ to test the SR
- Patient looks _____ to test the IR
- laterally
- UP
- Down
RAD SIN stands for?
Recti adduct, superiors intort
When eye is adducted, SO _____eye and IO ___ the eye
depresses the eye and IO raises the eye
When eye is abducted, SR ____ the eye and IR _____ the eye
raises, depresses
What type of deviation do you get with a CN III palsy and what is the common etiology
Eye is down and out with dilated pupil and complete ptosis - suspect aneurysm in PCA
What type of deviation do you get with a CN IV palsy and what is the common etiology
Eye is hyper, can see head tilt to opposite side of palsy - congenital or traumatic
What type of deviation do you get with a CN VI palsy and what is the common etiology
Eye is deviated towards nose. Usually traumatic, elevated ICP, ischemia from DM.
Blood supply to the eye is from the ____ artery which branches from the ____artery
Opthalmic, internal carotid
What are the 10 arteries of the orbit
A P C D M L L S S S
- Anterior Ethmoidal
- Posterior Ethmoidal
- Central retinal artery
- Dorsal nasal
- Medial palpebral arteries
- Lacrimal
- Long posterior ciliary arteries
- Short posterior ciliary arteries
- Supra orbital a
- Supra trochlear
what structures do the arteries of the orbit supply
- anterior ethmoidal: ethmoidal air cells, frontal sinus, nasal cavity, external nose
- Posterior ethmoidal: ethmoidal sinuses and nasal cavity
- Central retinal artery: Pierces CN II, and perfuses retina
- Dorsal nasal: Terminal branch to root of nose and lacrimal sac
- Medial palpebral: Central to arcades in upper and lower eyelids
- Lacrimal: Lacrimal gland
- Long posterior ciliary a.: ciliary body and iris
- Short posterior ciliary a: choroid
- Supra orbital: forehead and anterior scalp
10: Supra trochlear:forehead and anterior scalp
Venous drainage of the eyes is via the ___ and ___, which drain into the _____
inferior and superior opthalmic veins, cavernous sinus
Aqueous humor is secreted in the ____chamber by the _______. It enters the ______chamber through the ______ and drains through the ________ into the ______
posterior chamber, ciliary processes.
anterior chamber, pupil, trabecular meshwork, scleral venous channels
Dilator pupillae fibers are oriented in a ____ manner. This muscle is a ____ muscle that is innervated by the ______ system whose contraction causes pupillary _______
radial.
smooth, sympathetic, dilation
Sphincter pupillae fibers are oriented in a ______ pattern around the ____. this muscle is innervated by _______fibers. Its contraction causes pupillary _______
circumferential, pupillary margin.
post ganglionic parasympathetic.
Meiosis
The intraocular lens is composed of ____ and _____. Cataracts are result of the breakdown of the _____
water and proteins.
lens proteins
The vitreous is mainly composed of ____ and ____. It does not contain any _____
water and collagen fibers.
blood vessels
The anterior chamber is located between the _____ and the ____
iris and the cornea
Central retinal vein drains _____, leaves through _____, drains into _____
retina, CN II, superior opthalmic vein.
Vorticose veins, usually ____ in number, one from each quadrant of the _____. They pierce the sclera and drain into the ____ and _____
4, choroid.
superior and inferior opthalmic veins
What is the pathway of the efferent stimulation of the lacrimal gland
General visceral efferent fibers travel from CN VII –> greater petrosal nerve –>nerve of pterygoid canal –>pterygopalatine ganglion –>”hitchhike” with V2 branch (zygomatic) –>infraorbital fissure –> lacrimal nerve (V1) –> lacrimal gland
What are the three types of tears and the purpose of each
- Basal: Lubrication, cleaning, removal of bacteria (normal PS stimulation)
- Reflex: From irritation, wash irritants from the cornea
- Emotional: From emotional stress
Affarent = ____
Efferent =_______
trigeminal, fascial
Contraction of the ciliary muscle ______ the size of the ciliary body, which ___ the zonular fibers, causing the IOL to ____ for accomodation
decreases, loosens, thicken
V lesions
Reflex lacrimation is lost, but emotional and basal lacrimation are retained
VII lesions
Proximal to the geniculate ganglion; all lacrimation is lost, but tarsal, sebaceous, and conjunctival glands can sometimes keep eye lubricated.
The floor of the temporal fossa is formed by parts of the four bones that form the pterion:
frontal, temporal, parietal, and greater wing of sphenoid.
What are the soft tissue structures found in the infratemporal fossa
- Artery: Maxillary artery
- Venous plexus: Pterygoid plexus
- Nerves: Mandibular, inferior alveolar, lingual, buccal, and chorda tympani nerves
- ganglion: otic
What is the TMJ?
A synovial joint that allows gliding, rotation, flexion (elevation), and extension (depression) of the mandible.
What are the 6 components of the TMJ
- Mandibular condyles
- Articular surfaces of the temporal bone
- Capsule: Dense fibrous membrane that surrounds the joint.
- Articular disc: Fibrocartilgenous tissue separating the 2 bones of the TMJ
- Ligaments: 3; define farthest extensions of the mandible
- Lateral pterygoid muscle: Pull mandible forward (protractor)
The bony articular surfaces of the TMJ are the _______ of the temporal bone and head of thee ____
mandibular fossa, mandible
The orientation of the jaw for each action
- Depression _____
- Elevation ____
- Protrusion ________
- Retraction _________
- Opening
- Closing
- Mandible moves anteriorly
- Mandible moves posteriorly
What are the true muscles of mastication and their function and innervation
- Temporalis: Elevator, retractor - motor root of CN V3 (deep temporal branches)
- Masseter: Elevator, retractor - motor root of CN V3, (masseteric n)
- Medial pterygoid: Elevator, protractor, motor root of CN V3 (medial pterygoid n)
- Lateral pterygoid: Depressor, protractor, motor root of CN V3 (lateral pterygoid n)
What are the accessory muscles of mastication and their innervation
- Digastric muscle: Anterior belly inn. by V3, posterior belly inn. by V2
- Buccinator: CN VII
- Tongue: CN IX
- Orbicularis oris: CN VII
List all the nerves found in the infratemporal fossa
- Buccal
- Muscular branches of V3
- Inferior alveolar nerve
- Nerve to mylohyoid
- Lingual nerve
- Chorday tympani
- Auricotemporal nerve
Identify all the branches of the maxillary artery
- buccal
- masseteric
- Middle meningeal
- infraorbital
- mental
What is the name of the groove that runs from the mandibular foramen down toward the bottom of the mandible?
Mylohyoid groove
What is the soft tissue structures associated with this groove
Nerve to the mylohyoid which is a branch off the inferior alveolar nerve from V3.
List the 9 branches of the mandibular division of CN V
- Buccal
- Lingual
- Inferior alveolar
- Auriculotemporal
- masseteric
- meningeal branch
- Nerve to medial petrygoid
- Nerve to lateral pterygoid
- Deep temporal nerves
What are the following answers pertaining to in regards to the parotid gland
- Location
- Blood supply
- General afferent innervation
- Preganglionic parasympathetic
- Ganglion
- Postganglionic parasympathetic
- Sympathetic
- Side of face
- External carotid artery, superficial temporal artery
- Auriculotemporal nerve, great auricular nerve
- tympanic nerve and lesser petrosal nerve
- Otic
- Auriculotemporal nerve
- external carotid a plexus
What are the following answers pertaining to in regards to the submandibular gland
- Location
- blood supply
- General affarent innervation
- preganglionic parasympathetic
- ganglion
- postganglionic parasympathetic
- sympathetic
- sublingual and submandibular spaces
- submental branch of fascial artery
- Lingual nerve (V3)
- Chorda tympani (V2)
- SUbmandibular
- Lingual nerve (V3)
- External carotid a plexus
What does the frontal sinus do
These spaces fill up with mucus, which then drain into the nose. The draining process can be hindered by blockages, which often causes an inflammation of the frontal sinus. As mucus accumulates, this can cause infections.
What does the ethmoid sinus do
is located between the nose and eyes. It is very small at birth and becomes walnut-sized during puberty. The primary function of the ethmoid sinus, like all the sinus cavities in the skull, is to provide lubrication (mucus) to the inner nose
What does the sphenoid sinus do
The pituitary gland is housed in the sphenoid bone in the median section. This is also housed in the sella turcica.
What does the maxillary sinuses do
The largest of the paranasal sinuses and located below the cheeks. Maxillary sinusitis or an infection of the maxillary sinus can have the following symptoms: Fever Pain or pressure in face near the cheek bones Toothache Runny nose Sinusitis is the most common of maxillary sinus illnesses and is usually treated with prescription antibiotics. .
