Ocular Adnexa Flashcards
What hairs are the first to develop embryologically?
the eyebrows
Where are the eyebrows located?
across the supraorbital margin at the junction of the forehead and the upper eyelid
What nerve innervates the muscles of the eyebrow?
cranial nerve 7: facial nerve
what are the 4 muscles involved in moving the eyebrows?
frontalis, procerus, orbicularis oculi, and the corrugator supercilli muscle
Which two arteries supply blood to the eyebrows?
supraorbital and supratrochlear branches of the ophthalmic artery
What veins drain the eyebrows?
Drain anteriorly into the angular vein and then into the facial drain
Which nerves supply sensory innervation to the eyebrows?
centrally: supraorbital nerve
medially: supratrochlear nerve
Both branches of the ophthalmic division of the trigeminal nerve
What is another name for eyelids?
Palpebrae
Functions of the palpebrae
cover and protect the surface of the globe and distribute the tear film
What is the horizontal furrow called in the superior palpebrae?
superior palpebral sulcus
What do the superior and inferior palpebral sulci do?
spit the lid into orbital and tarsal parts
How is the superior palpebral sulci formed?
by the insertion of the fibers of the aponeurosis of the levator palebrae superioris into the tarsal plate
Which part of the eyelid is closer to the eyebrow, the orbital or tarsal part?
orbital
what are the corners of the eye called where the superior and inferior palpebrum meet?
medial and lateral canthus
What is the space where the globe is visible or eye opening called?
palpebral fissure
Which canthi lies directly on the globe?
the lateral canthus
What separates the superior and inferior palpebrae at the medial canthus?
lacus lacrimalis
what two structures are located in the lacus lacrimalis?
plica semilunaris and lacrimal caruncle
What is the overlapping piece of skin called in the medial angle?
epicanthus: can look like pseudoesotropia
What is the small mound called located on the medial portion of the palpebrae?
papilla lacrimalis
What is the small hole called on top of the papilla lacrimalis?
punctum lacrimalis for drainage of tears into the lacrimal canaliculi
How often are eyelashes replaced?
about 100-150 days
What is distichiasis?
an accessory row of lashes arising from the meibomian glands
What is trichiasis?
misdirected lash(s)
Where are the orifices of the meibomian glands located?
posterior to the cilia (inferior and superior)
Where is the mucocutaneous junction?
between the posterior edge of the orifices and the skin of the palpebral conjunctivia
Where is the gray line?
between the eyelashes and the orifices of the meibomian glands (divides the anterior and posterior portion of the eyelid)
How is the upper eyelid innervated?
Lateral to medial: lacrimal, supraorbital, and supratrochlear branches of the ophthalmic division of the trigeminal nerve
How is the lower eyelid innervated?
Lateral to medial: infraorbital and infratrochlear of the ophthalmic division of the trigeminal nerve
where does the infraorbital branch from?
the maxillary division of the trigeminal nerve
where does the infratrochlear branch from?
the nasociliary nerve of the ophthalmic division of the trigeminal nerve
What are the two main arteries supplying to the eyelids
lacrimal and ophthalmic arteries
what does the lateral lacrimal artery branch into?
superior and inferior lateral palpebral atery
what does the medial ophthalmic artery branch into?
superior and inferior medial palpebral artery
what do the superior and inferior medial palpebral artery branch into?
marginal and peripheral arteries
what do the superior and inferior lateral palpebral artery branch into?
marginal and peripheral arteries
what veins drain the medial portion of the eyelid
the angular and ophthalmic veins
what veins drain the lateral portion of the eyelid
superficial temporal vein
Where does the lateral 2/3 of the upper and lower eyelid lymph drain into?
preauricular nodes
where does the medial lymph of the eyelids drain into?
the submandibular nodes
what type of muscle is the orbicularis oculi
striated muscle fibers
where is the orbicularis oculi muscle located
encircling the eye elliptically around the orbital margin
what are the four parts of the orbicularis oculi muscle
1.orbital 2. palpebral 3. lacrimal 4. ciliary
where is the orbital portion of the orbicularis oculi muscle?
it encircles the palpebral portion
where is the palpebral portion of the orbicularis oculi muscle
it sweeps laterally and concentrically from the medial palpebral ligament and medial orbital margin to the lateral palpebral raphe
what is another name for the lacrimal portion of the orbicularis oculi muscle
muscle of horner
where is the lacrimal portion of the orbicularis oculi muscle located
it encircles the lacrimal canaliculi within the lids to aid in the excretion of tears
what is another name for the ciliary portion of the orbicularis oculi muscle
muscle of Riolan
where is the ciliary portion of the orbicularis oculi muscle located
it is a group of fine fibers located at the lid margin
what is the ciliary portion of the orbicularis oculi muscles function
keep the ciliary margin of the eyelid apposed to the eye
What is the action of the orbicularis oculi orbital portion
contacts like a pursestring drawing the lids toward the medial canthis and closing the fissure
what is the antagonist of the orbital portion of the orbicularis oculi muscle
the frontalis muscle
what does the palpebral portion of the orbicularis oculi do
voluntary wink or reflex blink
what is the antagonist of the palpebral portion of the orbicularis oculi
the levator palpebrae superioris- relaxes the lids
what does the lacrimal portion of the orbicularis oculi do
dilates the lacrimal sac
what innervates the orbicularis oculi muscle
the facial nerve (7)
what does the levator palpebrae superioris muscle do?
it is the elevator of the upper lid
where is the levator palpebrae superioris muscle located?
superior to the superior rectus muscle (their facial sheaths blend together)
What is the levator aponeurosis?
as the levator enters the upper lid it becomes a fan-shaped tendinous expansion
where do the fibers of the aponeurosis penetrate?
in the orbital septum
what two parts do the levator aponeurosis split into?
medial and lateral horns
what does the lateral horn of the levator aponeurosis spilt in half?
it divides the lacrimal gland into orbital and palpebral parts and holds the gland in place in the fossa
what does the lateral horn of the levator aponeurosis attach to
the lateral palpebral ligament
what does the medial horn of the levator aponeurosis attach to
the medial palpebral ligament and the medial orbital margin
what do the medial and lateral palpebral ligaments prevent?
keep the levator aponeurosis from pulling the lid up too far
What muscle relaxes as the levator palpebrae superioris is elevating the lid?
orbicularis oculi
what innervates the levator palpebrae superioris muscle
superior division of the oculomotor nerve (CN 3)
what is the superior tarsal muscle also called
muscle of muller
what type of muscle is the superior tarsal muscle
smooth muscle
where do the fibers originate for the superior tarsal muscle
levator muscle
what is the action of the superior tarsal muscle
helps to keep the lid up once the levator has lifted it
what innervates the superior tarsal muscle
postganglionic sympathetic fibers from the sympathetic plexus- from the superior cervical ganglion
what type of muscle is the inferior tarsal muscle
smooth muscle
what innervates the inferior tarsal muscle
postganglionic sympathetic fibers from the sympathetic plexus- superior cervical ganglion
where is the capsulopalpebral fascia located
in the lower lid (lower lid aponeurosis)
what is the function of the capsulopalpebral fascia
it retracts the lower lid and move it in tandem with the globe
what is the orbital septum
a tarsus/fibrous membranous sheet that is continuous with the periorbita at the orbital margin
what does the orbital septum separate
the contents of the eyelid from the orbital cavity, acts as a barrier
what perforates the orbital septum
the aponeurosis of the levator palpebrae superioris muscle
what are the tarsal plates made of
composed of dense fibrous connective tissue
what is the purpose of the tarsal plates
maintain the firmness and shape of the eyelids
what is housed inside the tarsal plates
meibomian glands or tarsal glands
where are the palpebral ligaments located
they attach the tarsi to the orbital margins
what are the palpebral ligaments made of
dense connective tissue
what is the purpose of the palpebral ligaments
to keep the lids apposed to the globe during ocular movement
what type of glands are the meibomian glands
sebaceous glands
how many rows of meibomian glands are on each lid
a single row with their orifices on the surface of the lid margin
what type of glands are the glands of zeiss
modified sebaceous glands
what is the purpose of the glands of zeiss
secrete sebum into the hair follicle of the cilia to keep moist
what type of glands are the glands of moll
modified sweat glands
what is the purpose of the glands of moll
secrete via ducts into the hair follicle or the ciliary margin of the lid
what are the 6 layers of the eyelid?
skin, subcutaneous tissue, striated muscle fibers (orbicularis oculi), orbital septum and tarsal plates, smooth muscle, and palpebral conjunctiva
what type of tissue is the skin
keratinized stratified squamous epithelium
what separates the palpebral conjunctiva and the skin
mucocutaneous junction
what type of tissue is the subcutaneous tissue
loose and rich in elastic fibers
