Orbit, Eye, & Vision Part 2 - Herring Flashcards
Muscles work _____ & work in _____
together ; teams
** think about it, you look to the left and the left eye uses a muscle to look laterally and the right eye uses a muscle to look medially **
Vertical axis movements of the eye = what directions?
medially or laterally (left and right)
Transverse axis movements of the eye = what directions?
Superior or inferior (up and down)
Anteroposterior axis movements of the eye = what directions?
Medial rotation (intorsion) or lateral rotation (extorsion)
(In and out aka towards the nose or not)
Anatomical movements of the eye ALWAYS starts from eye looking directly _______
forward
Isolation of Muscles or “Clinical” testing = ________ the muscle and starts from either eye in the ______ or _______ position
isolates ; medial ; lateral
What muscles of the eye are responsible for movements of eyeball or raising upper eyelid
Extrinsic (extra-ocular)
What muscles of the eye are responsible for controlling shape of lens & size of the pupil
Intrinsic
Why do Anatomical Movements ALWAYS start from eye looking directly forward (primary position; eye at rest)
Due to angled approach from origin to insertion, some muscles will have complex actions
Rectus Muscles originate as a group from
common tendinous ring
What muscles = fibrous cuff that surrounds optic canal & part of superior orbital fissure
rectus muscles
Rectus Muscles - Structures traveling through the common tendinous ring:
CN II
ophthalmic artery
nasociliary nerve
CN VI
superior & inferior division of CN III
The rectus muscles attach to _____ ½ of eyeball (same aspect as the pupil)
anterior
Anatomical Movements - Medial Rectus
Adducts the pupil which brings the pupil in medially (toward the nose)
Anatomical Movements - Lateral Rectus
Abducts the pupil
Brings the pupil out laterally (away from the nose)
Apex of orbit medial to axis of eyeball is the origin of what muscles
** they also pass laterally to attach to the eyeball **
Superior & Inferior Rectus
Anatomical Movements - Superior Rectus
Elevates pupil with adduction
Brings the pupil “up & in”
Anatomical Movements - Inferior Rectus
Depresses the pupil with adduction
Brings the pupil “down & in”
What muscles do NOT originate from common tendinous ring and angle to insertion
Oblique muscles
What muscles attach to the posterior 1/2 of the eyeball on the side opposite the pupil
Oblique muscles
Anatomical Movements - Superior Oblique
** also, where does it attach to on the eyeball?
Depresses the pupil with abduction
Brings the pupil “down & out”
Attaches to posterolateral half of the eyeball
Anatomical Movements - Inferior Oblique
Elevates the pupil with abduction
Brings the pupil “up & out”
Isolation of Muscles or “Clinical” testing - Starting position for elevation/depression movements is with the pupil in the _______ or _______ position (not looking straight ahead)
medial or lateral
To isolate lateral & medial rectus
Keep in horizontal plane (not any different than anatomical movements)
*** just asking them to look medially and laterally **
To isolate superior rectus, have patient:
Bring eye lateral (using lateral rectus)
Then UP
To isolate inferior rectus, have patient:
Bring eye lateral (using lateral rectus)
Then DOWN
To isolate superior oblique, have patient
Bring eye medial (using medial rectus)
Then DOWN
To isolate inferior oblique, have patient
Bring eye medially (using medial rectus)
Then UP
Eye misalignment
One eye is turned in a different direction than the other eye
Strabismus
Eye points downward
Hypotropia
Eye points outward
Exotropia
Eye points upward
Hypertropia
Eye points inward
Esotropia
Reduced vision in one eye due to abnormal visual development early in life (lazy eye)
Amblyopia
Oculomotor nerve (CN III) has ________ innervation
somatic motor
Superior division of CN III innervates what 2 muscles
Levator palpebrae superioris, superior rectus
Inferior division of CN III innervates
Medial rectus, inferior rectus, inferior oblique
PS pathway of CN III
has what kind of fibers
PreGPS fibers
PS pathway of CN III
The preGPS fibers synapse on what ganglion
Ciliary
the ciliary ganglion of CN III is composed of ________ cell bodies
PostGPS
PostGPS fibers of CN III hitch a ride on ____ ciliary nerves
short
PS pathway of CN III innervates what 2 muscles
sphincter pupillae and ciliary muscles
When CN III is lesioned, we can expect what 3 signs/symptoms
Dilated pupil
Ptosis (droopiness) of
upper eyelid
Pupil is directed “down &
out” at rest
CN VI has _________ innervation
Somatic motor
Lesion to the right CN VI when following your finger to the left:
Normal function of right medial rectus
(Both eyes look to the left normally)
Lesion to the right CN VI when following your finger to the right:
Abnormal function of right lateral rectus
(Right eye looks straight ahead while left eye looks right)
Lesion to the right CN VI
When the eyes are at rest (looking straight ahead)
Right eye in medial position due to unopposed action of medial rectus
(Right eye is inward a bit and left eye is looking straight ahead)
CN IV has __________ innervation to the _________ muscle
somatic motor ; superior oblique muscle
Lesion to the right CN IV
right pupil at rest (looking straight ahead) demonstrates slight
elevation
Lesion to the right CN IV
Right pupil demonstrates decreased depression from the ______ position
medial
Lesion to the right CN IV
Patient also presented with a mild head tilt to the ______
left (opposite side)
some muscles take an _________ approach because their origin is near the apex of the orbit
angled
Pull insertion towards the
origin
What are the extrinsic (extra-ocular) muscles
Levator palpebrae superioris, rectus mm, & oblique mm
What are the intrinsic eye muscles
Ciliary muscle, sphincter pupillae, dilator pupillae
Where is the common tendinous ring
apex of orbit
What is the only extraocular muscle with an anterior starting point
inferior oblique
What muscles elevate the pupil when looking straight ahead
superior rectus
inferior oblique
What muscles depress the pull when looking straight ahead
inferior rectus
superior oblique
once CN III is in the orbit, it divides into what 2 divisions
superior division
inferior division
The parasympathetic pathway of CN III only travels as part of the __________ division
inferior
