Kinematics Flashcards
(43 cards)
Define
- Origin
- Insertion
- Muscle cone
- Origin is where the muscle attaches to the bony orbit
- Insertion is where the muscle attaches to the globe
- Formed by the recti muscles. Origin at the annulus of zinn.
Kinematics is
The branch of classical mechanics that describes the motion of points, bodies, and systems of bodies without consideration of the forces that cause it.
Optic Neuritis
Inflammation of the optic nerve. Pain on EOMs may be an early sign. Could also present as an APD.
Spiral of Tilleaux.
Trend of how far the recti muscles insert from the limbus
Medial rectus has the most anterior insertion and the SR has the most posterior insertion.
The SR has a connected sheath with
The levator muscle. Coordinated eye movements with eyelids.
Angle of attachment for the SR and IR
23 degree from the Y axis (Ficks. Line of sight)
The IR Is exactly parallel with which other muscle?
The SR, which is important for coordinated movements. They should always match each other.
The IR passes above or below the IO?
Above
Lateral rectus origin
Upper and lower limb of the annulus of zinn and the process of the greater wing of the sphenoid.
Role of the lateral and medial check ligaments
They are both fascicle expansions of the muscle sheathes from the medial and lateral recti muscles. The check ligaments prevent eye from rotating into orbit.
Attachment of lateral rectus at lateral wall of orbit
Whitnall’s Tubercle
Origin of the medial rectus
Upper and lower annulus of zinn along with the ON stealth. Would result in pain with ON inflammation.
SO is at which angle to the Y axis
54 degrees
Anatomical origin of the SO
Physiological origin
Lesser wing of the sphenoid
Catilaginous trochlea on the superior medial orbit wall.
The muscle ends before the trochlea. The tendon passes through the trochlea.
Insertion of the SO
Lateral posterior globe. Behind equator of the globe, which is important for the function.
Superior oblique primary, secondary, and tertiary functions
Intorsion, abduction, and depression.
Origin of the IO
Maxillary bone inferior to nasolacrimal fossa
Insertion of the IO
Posterior lateral globe. Mostly inferior.
The IO has what degree angle with the visual axis/Y axis?
51
Tangential point
Where the center of the muscle or tendon first touches the globe. Tangent here indicates the direction of pull.
Tangential point can move. Changes when the muscle contracts or relaxes
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.
Muscle plane
Determined by a tangential point and the center of rotation. Describes direction of pull of the muscle. Determines the axis of rotation.
Axis of rotation is determined by
The muscle plane, which is determined by the tangential point.
The axis of rotation is that around which the muscle would rotate if contracting in isolation.
Strabismus Surgery. Resection.
A section cut out (not including the point of insertion) to make a shorter muscle/stronger pull.
MR for exotrope and LR for esotrope
