Midterm 1: Kinematics 1 Flashcards
Term for monocular eye movement medially
Adduction
Term for monocular eye movement laterally
Abduction
Term for monocular eye movement up
Supraduction, elevation
Term for monocular eye movement down
Infraduction, depression
Term for monocular eye rotation 12:00 position medially
Intorsion, Incycloduction, Incyclorotation
Term for monocular eye rotation 12:00 position laterally
Extorsion, Excycloduction, Excyclorotation
Term for monocular eye movement anterior, out of orbit
Protrusion, proptosis, exophthamlos
Term for monocular eye movement posterior, into orbit
Retraction, Enophthalmos
Term for binocular eye movement right
dextroversion
Term for binocular eye movement left
Levoversion
Term for binocular eye movement up
Supraversion
Term for binocular eye movement down
Infraversion
Term for binocular eye movement up and right
dextroelevation
Term for binocular eye movement up and left
Levoelevation
Term for binocular eye movement down and right
dextrodepression
Term for binocular eye movement down and left
levodepression
Term for binocular eye movement adduction
convergence
Term for binocular eye movement abduction
divergence
Term for binocular eye movement extortion
excyclovergence
Term for binocular eye movement intortion
Incyclovergence
Term for binocular eye movement right rotation
dextrocycloversion
Term for binocular eye movement left rotation
levocycloversion
rotation of a single eye
duction
rotation of both eyes
version
Name the 6 extra ocular muscles and what they are innervated by
Medial rectus (MR) - CN 3 Lateral rectus (LR) - CN 3 Superior rectus (SR) - CN 3 Inferior rectus (IR) - CN 3 Superior oblique (SO) - CN 4 Inferior oblique (IO) - CN 6
Orienting movement’s larger than about ___ degrees are normally achieved by a combination of head and eye movements.
20
the branch of classical mechanics that describes the motion of points, bodies (objects), and systems of bodies (groups of objects) without consideration of the forces that cause it.
kinematics
Where the muscle attaches to bony orbit.
A fixed attachment
origin
What is insertion? example using recti and tendons
- Where the muscle attaches to globe
- Recti become tendons prior to insertion
- Tendons penetrate Tenon’s to attach to the sclera
Describe the muscle cone of the eye
Formed by the recti, origin at annulus of Zinn (tendinous ring in the orbital apex)
Describe optic neuritis
Inflammation of optic nerve.
- could have pain on EOM’s
- If behind the eye, presence of an APD and pain on eye movements may be the only clues
The primary position (primary gaze) is the reference position for ocular rotation. Lines of sight are ________. Lines of sight are __________ to the line between their centers of rotation
horizontal; perpendicular
The _________ position is any movement directly horizontal or vertical from primary gaze.
secondary
A movement other than directly horizontal or vertical from primary gaze is considered to be _____________.
tertiary position
What is the field of action?
The position of gaze in which a particular EOM is the primary muscle responsible for getting the eye to that position.
-where the EOM is being assessed on the physiology H
How many cardinal positions for physiological H?
9
What movements does the x-axis on Fick’s axes correspond with?
horizontal
rotation around x-axis gives elevation/depression
What movements does the Y-axis on Fick’s axes correspond with?
line of sight
rotation around the y-axis gives intorsion/extorsion
What movements does the Z-axis on Fick’s axes correspond with?
Vertical
rotation around the z-axis gives abduction/adduction
Inferior oblique innervation, origin, insertion, and angle with visual axis
Innervation: CN 3
Origin: Maxillary bone inferior to nasolacrimal fossa
Only EOM originating in the anterior orbit
Insertion: Lateral posterior globe, mostly inferior
Below the anterior-posterior horizontal plane
Angle: 51* angle with the visual axis
Superior rectus innervation, origin, insertion, and angle with visual axis
Innervation: CN 3
Origin: superior annulus of Zinn & dural ON sheath
Insertion: obliquely into lateral antero-superior sclera
Angle: 23* angle with Fick’s Y-axis
-coordinated movement with levator
Inferior rectus innervation, origin, insertion, and angle with visual axis
Innervation: CN 3
Origin: inferior annulus of Zinn
Insertion: Oblique arc onto lateral antero-inferior sclera
6.7 mm from limbus
Angle: 23* angle with Fick’s Y-axis
Medial rectus innervation, origin, insertion
Innervation: CN 3
Origin: Upper and lower annulus of Zinn. Dural optic nerve sheath
Insertion: Vertical line spanning horizontal plane of the eye
Antero-medial globe
5.5 mm from limbus
Lateral rectus innervation, origin, insertion
Innervation: CN 6
Origin: Upper & lower limb of annulus of Zinn
Process of greater sphenoid wing (spina recti lateralis)
Insertion: Parallel to medial rectus
Antero-lateral globe
6.9 mm from limbus
Superior oblique innervation, origin, insertion
Innervation: CN 4
Anatomical Origin: Lesser sphenoid wing
Functional Origin: Cartilaginous trochlea, superior medial orbital wall. Muscle ends BEFORE trochlea, 2.5mm tendon passes through trochlea
Insertion: Lateral posterior globe, superior
What is the tangential point?
- Where the center of the muscle or tendon first touches the globe.
- Tangent here indicates the direction of pull.
- Position changes when the muscle contracts or relaxes, and the eye moves.
What is arc of contact?
- The arc formed between the tangential point and the center of the insertion on the sclera.
- Varies in length as the muscle contracts.
What is the muscle plane determined by? What does it describe? What does it determine?
- Determined by a tangential point and the center of rotation.
- Describes direction of pull of the muscle.
- Determines the axis of rotation.
What is field of fixation? What do its limits depend on? Is it larger mono or binocular?
Area within which central fixation is possible by moving ONLY the eyes.
Limits depend on: -Configuration of structures around the eye
-Refraction of the globe
Practical ____ includes head movements and is much larger
Field of fixation
Primary action of medial rectus (MR)
Primary: Adduction
Primary action of superior rectus (SR)
Primary: Elevation
Primary action of inferior rectus (IR)
Primary: Depression
Primary action of inferior oblique (IO)
Primary: Extorsion
Primary, secondary, and tertiary actions of superior oblique (SO)
Primary: Intorsion
Secondary: Abduction
Tertiary: Depression
Primary action of lateral rectus (LR)
Primary: Abduction
Suspensory ligament of Lockwood
Fascia below both contribute to ligament & connects lid movement with eye movement
What is the medial check ligament? Where does it attach? What does it do?
- Fascial expansion from muscle sheath
- Attaches to medial orbital wall
- Helps to hold the globe in place
What muscle may be visible in some people?
Medial rectus on a lateral gaze. Attachment is the shortest distance to the limbus.
Where does Whitnall’s tubercle attach?
At lateral wall of orbit
angle of superior oblique tendon with the line of sight at primary gaze
54 degrees
Angle of superior oblique tendon with the line of sight at full adduction. What happens at this angle?
0 degrees / parallel. The eye depresses and turns downward
Angle of superior oblique tendon with the line of sight when abduction. What happens at this angle?
36 degrees. Eye has intorsion
Transposition surgery for Strabismus
taking body of muscle and moving it inferiorly or superiorly
Recession surgery for strabismus
When they cut the muscle and place it further back on the globe
Resection surgery for strabismus
Shortening the muscle and then reattaching to its original insertion to the globe
True or False:
Practical field of fixation is larger than binocular and monocular field of fixation
True
