Anatomy Flashcards
What bones are involved in the orbit of the eye?
Orbital plate of frontal bone Orbital plate of ethmoid bone Lacrimal Maxilla Zygoma Sphenoid
What protects the eye from trauma?
orbital margins / orbital rim
What parts of the orbit are thinnest and affected by orbital blowout fractures?
Medial wall and orbital floor
What are the two parts of the orbicularis oculi muscle?
Orbital part
Palpebral part
What is the function of levator palpebrae superioris?
retracting the upper eyelid
What does the conjunctiva cover in the eye?
Lower eyelid and upper eyelid
Also covers sclera and cornea
What part of the eye does the cornea cover?
iris and pupil
What is the function of the conjunctiva?
defensive barrier to foreign bodies penetrating deep to it into the orbit
What apparatus is used in the production of tears?
Lacrimal Apparatus
Explain how tears are produced and collected in the eye
Lacrimal gland produces lacrimal fluid (tears)
Pushed over eye towards medial angle by eyelashes
Drains through lacrimal puncta
What are the 2 parts which make up the fibrous outer layer of the eye?
sclera
cornea
What is the name of the vascular layer in the eye?
UVEA
What are the 3 components of the uvea (vascular layer in the eye)?
3 part:
- iris
- ciliary body
- choroid
What is the main function of the choroid in the vascular layer?
nutrition and gas exchange
What type of fluid is found in the anterior segment?
Aqueous humour
What type of fluid is found in the posterior segment?
Vitreous Humour
Where are the anterior or posterior segments found?
Anterior segment = in front of lens
Posterior segment = behind lens
What is the main artery which supplies the eye?
Ophthalmic artery
The ophthalmic artery branches from the external carotid. TRUE/FALSE?
FALSE
Internal Carotid
What artery supplies the retina and where can it be found?
The central artery of the retina (end artery found within optic nerve)
What is the danger triangle?
Area of the face where infection can potentially track back up venous system to the eye
What is the area of most acute vision called and where is it located in the eye?
Fovea
found in the centre of the macula
Why is the optic disc thought of as the blind spot?
There are no photoreceptors in the disc
How many extraocular muscles do we have and what type of muscle fibre are they made up of?
7 skeletal muscles
4x Rectus, 2x Obliques, Levator Palpebrae Superioris
Name the 4 rectus extraocular muscles?
superior rectus
inferior rectus
medial rectus
lateral rectus
Where do the rectus muscles originate and insert?
origin = common tendinous ring
insertion = sclera
What are the two oblique extraocular muscles?
superior oblique
inferior oblique
What cranial nerve supplies the lateral rectus muscle?
Lateral Rectus ABDUCTS eye
=> CN VI ABDUCENS
What cranial nerve supplies the superior oblique muscle?
Superior oblique passes through TROCHLEAR pullley before inserting onto sclera
=> CN IV TROCHLEAR
What cranial nerve supplies the rest of the extraocular muscles?
CN III
Oculomotor
What parts of the face have sensory innervation from CN V1?
upper eyelid
cornea
conjunctiva
skin of middle of nose
Where does the maxillary division of the trigeminal nerve give sensory innervation?
skin of the lower eyelid
skin over the maxilla
skin over nostrils
skin/mucosa of the upper lip