Week 3 Wet Flashcards
(43 cards)
List the 7 bones that make up the orbit of the eye
- Lacrima
- Ethmoid
- Frontal
- Spenoid (Lesser and greater wing)
- Maxilla
- Zygomaticus
What are the various openings in the orbit of the eye?
Optic Foramen
Inferior and Superior Orbital Fissures
What passes through the optic foramen?
The optic nerve
Opthalmic artery
What passes through the inferior orbital fissure
Maxillary Nerve (V2)
What passes through the superior orbital fissure?
Oculomotor Nerve III
Trochlear Nerve IV
Opthalmic Nerve (V1)
Abducens Nerve (VI)
Opthalmic Veins
Why is the floor of the orbit weaker than the rest?
It contains the Inferior orbital groove
What are the contents of the orbit?
- Eye
- Opthalmic artery + branches
- Optic Nerve
- Extrinsic eye muscles
- Ligaments of the eye
- Lacrimal apparatus
- Orbital fat
What are the 3 layers of the eye and their constituent parts
Outer fibrous — Sclera & Cornea
Middle Vascular — Choroid, Ciliary body and Iris
Inner Sensory —- Retina
How is the eye divided into segments and chambers?
Lens divides it into the ant & post segments
The iris divides the anterior segment into ant/post chambers
What is found in the anterior and posterior segments?
Ant - Aqueous Humor
Post - Vitreous Humour
What produces aqueous humor and what are the functions of it and vitreous humor?
Aqueous humor - Ciliary Body. It maintians intraocular pressure
Vitreous humor - Cushions the retina
What do we call the part of the retina with maximum visual acuity?
Macula or Fovea Centralis
What forms the end of the retina anteriorly?
Ora Serrata
Just ant to the equator of the eye
List the intrinsic muscles of the eye?
Ciliaris
Constricter Pupillae
Dilator Pupillae
What are the locations, actions and innervation’s of the intrinsic muscles of the eye?
Ciliaris:
- Ciliary Body
- Accommodation
- Parasympathetic via III
Constrictor Pupillae:
- Pupillary border of the iris (Circular)
- Constricting pupil
- Parasympathetic via III
Dilator Pupillae:
- Iris (Radial)
- Dilates Pupil
- Sympathetic
List the extrinsic muscles of the eye?
Recti - Lateral, medial, sup & inf
Obliques - Sup & Inf
LPS - Levator Palpabrae Superioris
List the 6 main movements of the eye
Adduction (medial) Abduction (Lateral) Depression (Down) Elevation (Up) Intorsion (rotates towards midline) Extorsion (Rotates away from midline)
Describe the innervation of the extrinsic eye muscles
Most are by the III cranial nerve
Sup oblique is by the IV, its the only one with a trochlea hence the name of the nerve
Lateral Rectus by the VI, its the main abducter hence the name of the nerve.
RADSIN, mnemonic for extrinsic eye muscle actions
Recti ADduct Superiors INtort
- All the recti adduct (except obviousbly the lateral)
- Superior Oblique Intorts & Inferior oblique extorts
The opposite is also true:
- Both obliques abduct
What movements are performed by each extrinsic eye muscle
MEdial REctus - Adducts
Lateral Rectus - Abducts
Sup Rectus - Elevates, adducts and intorts
Inf Rectus - Depresses, Adducts and extorts
Sup Oblique - depresses, Intorts, Abducts
Inf Oblique - Elevates, Extorts, Abducts
Which extrinsic eye muscle is the only one not arise from the posterior aspect of the orbit
Inf Oblique
What ligaments prevent your eye from over abducting/adducting?
Medial & Lateral Palpebral Ligaments
What does the suspensory ligament do?
Supports and prevents downward displacement of the eye
Describe the blood supply of the orbit and eye
OPthalmic artery through Optic canal
Opthalmic veins which pass through Sup orbital fissure to reach the Cavernous sinus beyond