Week 3 Wet Flashcards
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
What and where is the lacrimal gland?
A gland that produces the watery constituent of tears
Found in the upper lateral part of the orbit
Excess tears eventually drain through the lacrimal duct on the medial side into the inf nasal meatus
Describe the innervation of the lacrimal gland
Parasympathetic innervation via Cr N VII
What are the ossicles?
Small bones of the middle ear
Malleus
Incus
Stapes
What joint type connects the ossicles?
Synovial
What part of which ossicle contacts the tympanic membrane?
Handle of the malleus
Which ossicle contacts the oval window?
Stapes
What are the names and functions of muscles related to the ossicles?
Tensor Tympani - Dampens sound by tensing the malleus
Stapedius - Stabilizes the stapes
With what areas does the middle ear communicate?
- Mastoid air sinuses
- Eustachian tube to nasopharynx
Where are the middle and inner ear found?
Within the petrous part of the temporal bone
Whats the distinction between the bony and membranous labyrinths of the inner ear?
The inner ear is made up of the bony labyrinth which contains perilymph
The inner ear contains the membranous labyrinth which contains endolymph
What makes up the vestibular apparatus?
3 Semicircular canals (Ant, Post, Lateral)
Utricle
Saccule
Describe the orientation of the vestibular, cochlear and facial nerves within the Internal auditory foramen
Looking straight through the foramen it can be divided into 4 even segments:
- Sup Ant containing 7th cranial nerve
- Inf Ant containing the Cochlear nerve
- Sup Post containing the sup vestibular nerve
- Inf Post containing the inf vestibular nerve
Which nerve runs through the middle ear and how?
Facial nerves runs through the wall of the middle ear in the facial canal
This is where it gives off the chorda tympani
what nerve is given off within the middle ear cavity, from where and what does it do?
Facial nerve gives off the Chorda Tympani
It innervates the Ant 2/3rd of the tongue with taste sensation and secretomotor parasympathetic fibres to the submandibular/sublingual salivary glands
What does the sup oblique depress rather than elevate the eye (& vice versa for inf oblique)?
Because they connect to the posterior aspect of the eyeball itself
What are the terminal lymph nodes for most of the head and neck?
Deep Cervical Nodes
They are a linked chain around the IJV within the carotid sheath
What happens to lymph in the neck after the deep cervical nodes?
The nodes join to form the Jugular lymphatic trunk on either side which then drain into the Right Lymphatic duct or Thoracic Duct
What are the main regional lymph nodes of the head?
- Parotid Nodes (Over/in Parotid)
- Buccal Nodes (over buccinator)
- Submental
- Submandibular
- Mastoid
- Occipital
What are the main regional lymph nodes of the neck?
- Anterior Cervical chain (On ant jugular, draining ant neck)
- Superficial Cervical (On EJV, drain junction between head, scalp and neck)
- Retropharyngeal (Between pharynx & vertbra)
- Laryngeal
- Tracheal
