Orbital Contents Flashcards Preview

Neuro Block 2 > Orbital Contents > Flashcards

Flashcards in Orbital Contents Deck (52):

How does the location of the ciliary glands and the tarsal glands differ?


Why does blood pool in the eyelid with injury to the area?

There is a loose connective tissue layer just under the skin which allows for accumulation of blood as in a black eye


What is the function of the orbicularis oculi muscle?

it surrounds the orbit as a sphincter and is a facial muscle under voluntary control of the facial nerve.

It helps close the eyelid


What are the tarsal plates?

The tarsi are thin plates of fibrous CT in each lid

the upper is larger


they are attached to the palpebral ligaments laterally and medially and to the orbital septum


What is the orbital septum?

palpebral fascia

it's fibrous membrane that attaches to the margins of the bony orbit

for the upper lid, it joins the tendon of the leavot palpebrae muscle and attaches to the superior tarsus

In the lower lid it also attaches to the tarsus

Ultimately, it forms a barrier between the inside and outside contents of the orbit


Define palpaebral and bulbar conjunctiva/conjuncitval sac

the conjunctiva in general is a mucous membrane deep to the tarsi and septum that lines the eyelids

the palpebral portion is thick, red and lines the insdie of the eyelids

the bulbar portion is over the sclera - it's thin and transparent (over the cornea only the epithelial part is present)

the conjunctival sac is a space lined with conjuncitva that lies in front of the eye when the lids are closed


Where does the levator palpebrae muscle originate and insert?

It originates from bone above the optic foramen

inserts via a broad aponeurosis onto the anterior surface of the superior tarsus muscle, whose tendon penetrates the the orbital septum


What two types of muscles are associated with the levator palpebrae muscle?

the levator palpebrae superioris is a skeletal muscle

the superior tarsal muscle (muller's muscle) is smooth muscle


How is the levator palpebrae innervated?

the levator palpebraae is innervated by the occulomotor nerve


What is Horner's syndrome?

Horner's syndrome is  an interruption of sympathetic nerves inducing ptosis, pupillary constriction, flushin of the face and anhidrosis


How does the sensory innervation of the upper and lower eyelids differ?

sensory innervation is from the palpebral branches of the supraorbital, supratrochlear, infratrochlear and lacrimal branches of V1 (trigeminal) and palpebral branche sof the infraorbital of V2


What is the major blood supply and lymphatics to the eyelids?

arteries: lacrimal and ophthalmic arteries both have palpebral branches (veins similar to arteries)

lympnatics; lymph from the upper lid drains to the superficial parotid and superficial cervical nodes; lower lid tends to drain to the submandibular nodes


What glands are infected in a sty?

It's a suppurative inflammation of the ciliary (sebaceous) glands or a meibomina (tarsal) gland


What is conjunctivitis?

Inflammation of the bulbar and palpebral conjunctiva - may be caused by bacteria, viruses, irritating fumes, or allergies

more common in children


Injury to what two nerves may produce ptosis?

lesion of the oculomotor nerve or sympathetic nerves innervating the smooth muscle of the superior tarsus muscle (Muller's muscle)


What nerves are involved in the blink reflex?

facial nerve and trigeminal nerve (V1)


Where is the lacrimal gland located?

In the lacrimal fossa on the sueprior lateral aspect of the roof of the orbit

(separated form the eyeball by the levator palebrae and lateral rectus muscles)


What sensory nerve fibers reach the lacrimal gland?

the sensory supply is via the lactrimal nerve of the trigeminal V1


How do the autonomic secretory fibers reach the lacrimal gland?

the secretomotor fibers from the facial nerve (via the greater petrosal nerve)

the facial nerve carries preganglionic fibers to the pterygopalatine ganglion

postganglionic fibers leave thorugh the ygomatic branch of the maxillary (V2) to the communicating branch leading to the alcrimal nerve that leads to the lacrimal gland



What are the lacrimal canaliculi?

they are the lacrimal ducts

they are located at the medial end of each lid - both terminate in the lacrimal sac


Where is the lacrimal sac located and where does the nasolacrimal duct being and end?

the lacrimal sac is in the lacrimal groove formed by the lacrimal bone and the forntal process of the maxillary bone

the sac empties into the nasolacrimal duct, which terminates in the inferior meatus of the lateral nasal cavity


WHat nerves are involved in the tearing reflex?

the sensory root of the trigeminal enrve or the ophthalmic nerve (V1)


What is the shape of the orbit and how do the medial and lateral walls compare?

The orbit is pear-shaped with the apex posteirorly and the base anteriorly

the orbit slopes inferiorly from medial to lateral


What sinus is located below the floor of the orbit and hwhat type of fracture involves the orbit contents sinking into it?

The maxillary sinus

"blow-out" fractures


What cranial foss ia located above the roof of the orbit?

the anterior cranial fossa


WHat sinus is associated with the roof of the orbit?

frontal sinus


How is the orbital septum formed and what is its relationship to the tarsal plates?

THe orbital septum is continuous  with the periorbita at the margins of the base of the orbit.

in the upper lid is joins tendons of the levator palpebrae muscle

in both lids it attaches to the plates


What is the vagina bulbi (tenon's capsule)?

It's the bulbar fascia - thing membrane that envelopes the eyeball from the optic nerve to the level of the ciliary muscle


How are the medial and lateral check ligaments and suspensory ligaments of the eyball formed?

They are extensions of the bulbar fascia (vagina bulbi) from the lateral and medial rectus muscles to the lacrimal and zygomatic bones

thought to check the aciton of their respective muscles


What is the periorbita?

periorbita is just a special term for periosteum that lines the orbit


Through what foramen does the optic nerve enter the orbit?

optic foramen


Through what opening does the ophthalmic nerve enter the orbit?

nerve travels along the lateral wall of the cavernous sinus and enters the orbit through the superior orbital fissure


What are the three branches of the ophthalmic nerve and what areas are supplied by each?

Lacrimal (to the lacrimal gland)

Frontal (runs over levaotor palpebreae to divide into supraorbital nerve for sensortion to upper lid, forehead and scalp and  supratrochlear nerve for sensory to the conjunctiva or uppe rlid and forehead)

nasociliary (passes below superior rectus and superior oblique muscles to the medial wall of the orbit - long ciliary for sensory to eyeball, infratrochlear for sensory to the medial agnel fo the eye, and anterior and posterior ethmoidales for the forntal, ethmoid and sphenoid sinuses plus nasal cavity)


What is the function of the long ciliary nerve?

sensory to the eyeball, especialy the sclera and cornea


Why is the sympathetic root of the ciliary ganglion derived from the nasociliary nerve?


Where are each of the motor nerves in the cavernous sinus and where do the nerves enter the orbit?

Oculomotor in the lateral wall of cavernous sinus

trochlear in lateral wall of signus between CN3 and V1

abducens through the cavernous sinus between internal carotid and V1


Which extre-ocular eye muscle does not attach to the tendinous ring?

inferior oblique


WHat is the relationship of each of the CN innervating the extraocular ey emuscles to the common tenindous ring?


How do parasympathetic and sympathetic nerves reach the lacrimal gland?

parasympathetic: preganglion from cells in superior salivary nucleus with fibers running in the nervus infermedius of the facial nerve then to the ggrater petrosal nerve which synapses in the pterygopalatine ganglion. postganglionic fibers from the pterygopalatine ganglion pass through in the maxillary nerve V2 and then thorugh the zygomatic branch of tV2 to communicate with the lacrimal branch of the ophthalmic nerve V1 to reach the lacrimal gland

sympathetic: preganglionic fibers in intermediolateral gray column of upper thoracic cord enter the sympathetic trunk and ascend in cervical sympathetic turnk to synapse in superior cervical ganglion, after which the postganglionic fibers pass thorugh carotid plexu and continue rostrally in the deep petrosal nerve, passing throuhg tperygopalatin ganglion (w/o synapse) and then runw ith the parasympathetic postganglionic to synapse on lacrimal gland


How do the sympathetic and parasympathetic nerves reach the iris and ciliary muscles?

Iris: parasympathetic preganglionif fibers from the edinger westphal nucleus in the occulomotor nerve to the ciliary ganglion. postganglionic fibers travel to the constricto pupillae muscle of the iris int he short ciliary nerves

sympathetic - go to dilator pupillae muscles. preganglionis from intermediolateral gray colun to the superior cervical ganglion. postgnaglions to carotid and cavernous plexuses then through the nasociliary branch of V1.


How is an increase in ICP transmitted along the optic nerve?

The optic nerve is surrounded by a heavy external sheath which is continuous with the dura, arachnoid and pia f the cranial cavity. Between the pia and arachnoid is the intervainal space which is a continuation of the subarachnoid space where CSF pressure can increase and be transmitted to the back of the eye ball, resulting in swelling of the optic disc (papilledema)


How does the ophthalmic artery enter the orbit?

THrough the optic foramen, below and lateral to the optic nerve


How do the superior and inerior ophthalmic veins connect the face with the cavernous sinus?

they usually drain posteriorly into the cavernous sinus


What is the blind spot?

the area of the retina where the optic nerve fibers leave the eyeball and the retinal vessels disappear - no rods or cones there


What is a choked disk and how is it caused by ICP?

a choked disc is papilledema, resulting in swelling due to increased increacranial pressure


From what artery does the central artery originate?

the opgthalmic artery originates in the internal carotid artery


How does the middle cranial fossa connect with the orbit?

temporal? infratemporal?


What is diplopia and what can cause it?


WHat is exophthalmos?


What is the significant danger of thombophlevitis of the facial vein or facial infections in the area of the orbit?