Head and Neck 5 Flashcards
Name the bones forming the roof of the orbit.
Mainly orbital plate of frontal bone
Lesser wing of sphenoid
Name the bones forming the medial wall of the orbit.
Ethmoid with contributions from maxilla, lacrimal and sphenoid
Anteriorly indented by lacrimal groove
What forms the floor of the orbit?
Maxilla
Some of zygomatic bone
What partly separates the floor and lateral wall of the orbit?
Inferior orbital fissure
What makes up the lateral wall of the orbit?
Zygomatic
Greater wing of sphenoid
Where does the superior orbital fissure lie?
Between greater wing and lesser wing of sphenoid
Where is the apex of the orbit located?
Apex is at the optic canal, medial to superior orbital fissure
What are the eyelids (palpebrae) covered by?
Thin skin
Internally covered by conjunctiva
What strengthens the eyelids?
Tarsal plates (dense fibrous bands)
What are the tarsal glands called?
Meibomian glnads
What is the function of the tarsal (Meibomian glands)
Secretion lubricates eyelids and prevents them from sticking together
Medial Palpebral Ligament
Connects eyelids to medial margin of orbit
Lateral palpebral ligament
Connects eyelids to lateral margin of orbit
What are the function of the medial and lateral palpebral ligaments?
Keep the covering of the eye stable
Where is the lacrimal gland found?
Fossa in lateral part of roof of orbit
Upper outer quadrant
What is the function of the lacrimal gland?
Produces tears
Which nerve is responsible for tear secretion?
Branch of facial nerve
Greater petrosal nerve
Which side do tears drain?
Medial side
What connects the palpebral fissure to the lacrimal sac?
Canaliculi (openings on median side)
What is the space between two eyelids called?
Palpebral fissure
Where is the lacrimal sac found and what is its function?
Lodged within the lacrimal groove
Collects extra tears
What is the lacrimal sac continuous with?
Nasolacrimal duct (this opens into inferior meatus of nose)
What is the puncta?
Small openings which push tears into lacrimal sac
Where is the levator palpebrae superioris found?
In roof of orbit, close to apex to tarsal plates and skin of eyelid
What is the function and innervation of levator palpebrae superioris?
Innervation = oculomotor nerve III
Elevates upper eyelid
What is Horner’s Syndrome?
Autonomic nerves (sympathetic) are trapped with damaged oculomotor nerve - partial ptosis, dilated pupil
Where does the superior rectus run?
Below levator palpebrae superioris
From common tendinous ring at apex of orbit to superior surface of eye
What is the function of the superior rectus?
Elevates the eye
Where is the inferior rectus found and what is its action?
Common tendinous ring to inferior surface of eye
Depresses eyeball
Where is the medial rectus found?
From common tendinous ring at apex of orbit to medial surface of eyeball
Below superior oblique
What is the action of medial rectus?
Adducts the eye
Where is the lateral rectus found, what is its action and innervation?
Lateral rectus from common tendinous ring to lateral surface of eye.
Abducts eyeball
Abducens Nerve (6)
Where does the superior oblique muscle lie?
From body of sphenoid, tendon passes through a fibrous ring (trochlea) at supero-medial angle of orbital wall, changes direction and inserts into slcera deep to superior rectus muscle
What is the action and innervation of the superior oblique muscle?
Trochlear nerve (4) Depresses eye, abducts eye (down and out)
Where does the inferior oblique muscle lie?
From anterior part of floor of orbit to sclera deep to lateral rectus
What is the function of the inferior oblique?
Elevates and abducts eye
Which eye muscles produce movement that is straight up?
Inferior oblique (up and out), superior rectus (up and In) - in and out movements cancel each other out
Which eye muscles produce vertically down eye movement?
Inferior rectus (down and in), superior oblique (down and out). In and out cancel
What is the nasociliary nerve a branch of?
V1
What branches does the nasociliary nerve give off?
Long ciliary Nerves
Posterior and Anterior Ethmoidal Nerves
Infratrochlear Nerve
What do the long ciliary nerves carry?
Sensory innervation to cornea
Sympathetic (postganglionic sympathetic fibres from superior cervical ganglion) to dilator pupillae muscles = dilates pupils
What does the anterior ethmoidal nerve become and when?
Becomes the external nasal nerve when it enters the face via the nose
What does the infratrochlear nerve supply?
Skin on medial side of lip and along external nose
Where is the ciliary ganglion situated?
Behind the eyeball, lateral to optic nerve and superior to arteries
What is the function of the ciliary ganglion?
Relay centre for parasympathetic fibres brought in by oculomotor nerve
What does the short ciliary nerves do?
Carry postganglionic (ciliary ganglion) parasympathetic fibres to the sphincter pupillae and ciliary muscles = constrict pupil
Which cranial nerves have parasympathetic axons?
3, 7, 9 and 10
Where does the ophthalmic artery come from?
ICA as it emerges from the cavernous sinus
Where does the ophthalmic artery travel?
Accompanies optic nerve into the orbit through the optic canal
What supplies the retina?
Central artery of the retina
What do the ophthalmic veins connect with?
Cavernous sinus and facial vein (as well as the pterygoid plexus of veins)
What supplies the auricle of the external ear?
V3 (sensory supply) - auriculotemporal nerve
What is the ear canal made of??
Lateral third is cartilaginous
Medial 2/3rds is bony (petrous temporal bone)
Which glands produce cerumen (ear wax)?
Ceruminous and sebaceous glands
What is the tympanic membrane covered by?
Simple squamous externally
Columnar epithelium internally
What is the middle ear and what does it contain?
Tympanic cavity directly internal to the membrane
Contains auditory ossicles linking tympanic membrane to oval window of inner ear
Name the bones found in the middle ear.
Malleus, incus and stapes
Which bone connects the inner ear to the oval window?
Stapes
Name the two small muscles in the middle ear.
Tensor tympani (handle of malleus - V3) = tenses tympanic membrane Stapedius (stapes - VIII) - dampen excessive movement on loud noises
What does the auditory tube open into?
Opens into tympanic cavity on lateral end and nasopharynx on medial end
What is the central part of the inner ear?
Vestibule
What lies anterior and posterior to vestibule?
Anterior is the cochlear
Posterior is the semicircular canals
What nerve supplies the inner ear?
VIII
Where does VIII divide?
Lateral end of internal auditory meatus
Into vestibular and cochlear portions
