Adnexa and Skull Flashcards
telecanthus
an abnormally increased distance between the medial canthi of the eyelids
poliosis
whitening of the eyelashes
madarosis
loss of eyelashes
trichiasis
turning inward of the eyelashes, often secondary to entropion
phthiriasis palpebrarum
infection of the eyelashes caused by Phthirus pubis
epicanthus
vertical fold of skin at inner corner, may give appearance of crossed eyes
exophthalmos/proptosis
protrusion of the globe, can be caused by inflammation, tumours, edema, injuries, thyroid ophthalmopathy (Graves disease)
enophthalmos
sinking in of the globe, after trauma, reconstruction surgery x10% risk
the eyelid is vascularized by?
facial artery and infraorbital (external carotid) and also internal carotid through the ophthalmic a -> medial palpebral and then lacrimal a -> lateral palpebral artery with medial palpebral form palpebral arcades
lagophthalmos
incomplete closure of the eyelids
periorbita
dense connective tissue covering the bones of the orbit, attachment site, projects anteriorly to become the orbital septum and posteriorly to fuse with the dura of the optic nerve
orbital fat
in upper lid: large and central and medial fat pad separated by trochlea
in lower lid: 3 compartments
orbital septum
thin, membranous sheet that acts as the anterior boundary of the orbit, strong, prevents facial infections from entering the orbit, holds orbital fat in its place
continuous with the periorbita and periosteum of the skull, attaches medially to the posterior lacrimal crest (lacrimal sac is anterior to the septum therefore the septum does not protect the lacrimal sac from infection), superior orbital septum also serves as the insertion site for the levator aponeurosis
tenon’s capsule (fascia bulbi)
thin, sheet of dense connective tissue that encases the globe, protects and supports, muscles go through it
suspensory ligament (of Lockwood)
part of bulbar sheath, “hammock” that runs below globe, keeps the eye from displacing downward
palpebral ligaments
dense bands, connect tarsal plate to the orbital rim
medial ligament attaches to the lacrimal crest and the lateral ligament attaches to the lateral orbital tubercle
what are the main forehead muscles involved in facial expression?
corrugator supercilli muscles (two heads), frontalis muscle, and procerus muscle
Horner muscle (a.k.a. pars lacrimalis)
branch of the pretarsal palpebral portion of the orbicularis oculi, encircles canaliculi and helps with tear drainage into the lacrimal sac
What are the two main portions of the orbicularis oculi?
orbital portion - attaches to the orbital margins and extends outward, used for forced closure of the eyelids
palpebral portion - used for spontaneous and reflex blinking, includes the muscles of Riolan and Horner
muscle of Riolan (a.k.a. pars ciliaris, or gray line)
terminal extension of orbicularis oculi, keeps the lid margin tightly on the globe, may contribute to rotating the eyelashes towards the eye on eyelid closure. the gray line is between the eyelash insertions and the meibomian glands, dividing the lid into anterior and posterior and is used as a landmark during sx
ectropion
lower lid droops away from the globe, can be caused by the paralysis of the orbicularis muscle
Meibomian glands
large sebaceous glands, embedded in tarsal plate posterior to the eyelash follicles, make lipid layer of the tears
glands of Zeis
modified sebaceous glands, secrete sebum into hair follicle of eyelashes
glands of Moll
modified apocrine sweat glands located near lid margin, empty contents onto eyelash follicles, Zeis glands, and the lid margin
accessory lacrimal glands of Krause and Wolfring
produce tears (aqueous layer), located in the fornices of the conjunctiva (Krause) and in the tarsal conjunctiva (Wolfring)
plica semilunaris
fold of conjunctiva in nasal corner of eye
papilla (of eyelid)
raised area on nasal lid containing the punctum, responsible for keeping the puncta open
margin reflex distance
measured from corneal light reflex to the lid, MRD1 is the top part and MRD2 is the bottom half, together makeup the interpalpebral fissure (IPF) which is on average 9-12mm
superior levator palpebral muscle (LPS - levator palpebrae superioris)
main retractor of the upper lid, originates from the lesser wing of the sphenoid, innervated by CNIII, joins to Whitnall’s ligament anteriorly and then to fibrous levator aponeurosis (fan-shaped tendon) which becomes contiguous with orbital septum and reaches to the tarsal plate (also forms the superior palpebral furrow)
Whitnall’s ligament
superior transverse ligament on the zygomatic bone that serves as a fulcrum and changes the course of the LPS muscle from anterior-posterior to superior-inferior
levator aponeurosis
ligament of the LPS, fan-shaped, extends into the eyelid anteriorly through the orbital septum to attach to the anterior surface of the tarsal plate (forms the superior palpebral furrow), lateral horn of aponeurosis travels across the lacrimal gland and attaches to Whitnall’s ligament, the medial horn merges with the medial palpebral ligament.
reflex blinking
responds to somatosensory (CNV), sound (CNVIII), light (CNII)
superior palpebral furrow/sulcus
formed by the insertion of the levator aponeurosis into the skin of the upper eyelid
inferior palpebral furrow/sulcus
formed by the indirect attachment of the inferior rectus muscle into the skin of the lower eyelid, separates the tarsal and orbital portions of the eyelid
muscle of Muller (a.k.a. superior tarsal muscle)
widens the palpebral fissure by providing 1-3mm of upper eyelid lift (minor retractor), smooth muscle (a2 receptor/sympathetic NS - reason for ptosis in Horner’s syndrome), originates on the levator and extends into the tarsal plate
inferior tarsal muscle
originates from the facial sheath of the inferior rectus and extends into the tarsal plate, provides minor lower lid retraction, innervated by sympathetic NS
which nerves lead to the opening and then the closing of the eye?
CNIII opens the eye, CNVII closes the eye
tarsal plate
dense irregular connective tissue that provides rigidity to the eyelids, composed of horizontal and vertical collagen fibrils that surround the meibomian glands
palpebral conjunctiva
contains goblet cells, stroma (substantia propria/submucosa) contains a superficial lymphoid layer and a deep fibrous layer
what does the superficial lymphoid layer of the palpebral conjunctiva contain?
very immunologically active layer, contains IgA, macrophages, mast cells, PMNs, and eosinophils
goblet cells
in the conjunctiva, (temporal bulbar and inferonasal fornix most predominant location), produces the mucin layer of the tear film
Which glands in the eyelid are holocrine, apocrine, or merocrine?
holocrine - meibomian glands, glands of Zeis
apocrine - glands of Moll and goblet cells
merocrine - accessory lacrimal glands
Which vitamin deficiency is associated with a loss of goblet cells?
Vitamin A deficiency involves loss of goblet cells and keratinization of the conjunctiva
palisades of Vogt
fibrovascular ridges perpendicular to the corneal margin more prominent on top and bottom, contain corneal stem cells, undulations increase surface area, melanocytes protect limbal stem cells from UV damage
What are the nerves of the eyelid, voluntary motor, involuntary motor, and sensory?
voluntary motor - zygomatic branch of CNVII, innervates the orbicularis oculi
involuntary motor - sympathetic NS innervates the muscle of Muller
sensory - different branches of CNV: upper lid is from the frontal (supraorbital and supratrochlear) and lacrimal branches of V1, and the lower lid is from the infraorbital and zygomaticofacial branches of V2
what artery supplies the bulbar conjunctiva and ciliary body?
anterior ciliary arteries (affected in uveitis -> circumlimbal injection), make up MACI, two for each recti muscle except LR (makes LR more susceptible to ischemia)
where does conjunctival lymphatics drain to?
laterally to the parotid (preauricular) lymph nodes and medially to the submandibular lymph nodes
frontalis
main elevator of the eyebrows and forehead, often used to compensate for a ptosis, innervated by CNVII
corrugator
medial depressor of the eybrow (look of concentration), innervated by CNVII
procerus
medial depressor of the eyebrow (look of menace/aggression), innervated by CNVII
orbicularis oculi
primary lateral depressor of the eyebrow, innervated by CNVII, has an orbital portion and a palpebral portion, closes eye (main protractor)
optic canal
located in the lesser wing of sphenoid and contains the optic nerve and ophthalmic artery
greater wing of sphenoid
connects with zygomatic bone to form the lateral wall of the orbit, also contains foramen rotundum, foramen ovale, and foramen spinosum
foramen rotundum
passage for the maxillary division (V2) of the trigeminal nerve
foramen ovale
passage for the mandibular division (V3) of the trigeminal nerve and the lesser superficial petrosal nerve
foramen spinosum
passage for the middle meningeal artery
superior orbital fissure
opening between the greater and lesser wings of the sphenoid bone - located between the posterior lateral wall and the superior wall of the orbit, common tendinous ring lies just anterior to the SOF
cavernous sinus
lies posterior to the SOF within each eye and travels on the sides of the sphenoid body
common tendinous ring (a.k.a. annulus of Zinn)
a circular band of connective tissue that lies just anterior to the SOF and serves as the origin of the recti muscles.
nasociliary nerve (branch of V1), oculomotor nerve (CNIII), abducens nerve (CNVI), and the sympathetic root of the ciliary ganglion (travels with nasociliary nerve) all go through the CTR and the SOF (acronym NOA)
which structures pass through the SOF but above the CTR?
superior ophthalmic vein, frontal nerve, lacrimal nerve, and the trochlear nerve
“LFT”
what goes through the optic canal (optic foramen)?
optic nerve (CNII) and ophthalmic artery
(optic canal goes through the lesser wing of sphenoid)
what goes through the carotid canal?
internal carotid artery and the sympathetic plexus
what goes through the supraorbital foramen?
supraorbital nerve (V1) and vessels (supra-orbital artery and vein)
what goes through the infraorbital foramen?
infraorbital nerve (V2) and vessels (infraorbital artery and vein)
what goes through the mandibular foramen?
inferior alveolar nerve and vessel
what goes through the stylomastoid foramen?
facial nerve (CNVII)
what bones make up the roof of the orbit?
2: frontal bone and lesser wing of sphenoid (Front-Less)
what bones make up the floor of the orbit?
3: maxillary, palatine, and zygomatic bones (My Pal gets his Zzzz’s on the floor)
what bones make up the lateral wall of the orbit
2: zygomatic and greater wing of sphenoid (the Great Z)
what bones make up the medial wall of the orbit
4: body of sphenoid, maxillary, ethmoid, lacrimal (SMEL)
which wall of the orbit is the weakest?
the floor
which wall of the orbit is the thinnest
medial wall
which wall of the orbit is the strongest?
lateral wall
caruncle
a hybrid of conjunctiva and skin that contains sebaceous glands, sweat glands, and goblet cells and is located on the medial side of the plica semilunaris
what innervation does the lacrimal gland receive?
parasympathetic innervation from the lacrimal nerve of the pterygopalatine ganglion of CNVII
what is the function of the lacrimal gland?
parasympathetic stimulation causes secretion of the aqueous layer of the tears
acute dacryoadenitis
an infection and/or inflammation of the lacrimal gland, can result in acute swelling and discomfort in the upper lateral eyelid
how long are the canaliculi?
10mm = runs 2mm vertically and then 8mm horizontally before joining into the common canaliculi that enters the lacrimal sac
the lacrimal sac
10-12mm long, lined with double epithelium with microvilli and goblet cells, continuous with the nasolacrimal duct
in between the posterior lacrimal crest of lacrimal bone and the anterior lacrimal crest of the maxilla
is the orbital septum anterior or posterior to the lacrimal sac?
posterior! the lacrimal sac is not protected by the orbital septum and so is more susceptible to infections
dacryocystitis
an infection of the lacrimal sac, usually occurs as a result of nasolacrimal duct obstruction (in kids)
how long is the nasolacrimal duct?
15mm, lies adjacent to the maxillary sinus
what is the name of the valve located at the end of the nasolacrimal duct?
Valve of Hasner
what are the two compartments for adipose tissue in the orbit relative to the EOMs?
intraconal - adipose tissue located WITHIN the muscle cone of the four recti muscles, serves to separate them from the optic nerve
extraconal - adipose tissue located OUTSIDE the muscle cone between the EOMs and the walls of the orbit
What goes through the cavernous sinus?
CN3, 4, 6, V1, V2
(V3, and CN7 DO NOT)
