Eye Movements
Vergence of both eyes moving away from the midline?
Divergence
Forms the oculomotor foramen?
Common tendinous ring (annulus of zinn)
Largest EOM?
Medial rectus
Origin: anatomic - sphenoid bone (lesser wing), physiologic - trochlea
Insertion: superior, posterior, lateral globe
Action: primary - intorsion, secondary - depression and abduction
Innervation: CN IV
What EOMs have more than one directions of movement from primary position?
Vertical recti and obliques
Primary position?
Head erect, eyes straight, focused toward infinity
Line connecting the insertion points of rectus muscles?
Medial rectus origin, insertion, action, and innervation
Insertion: anterior part of the globe
Action: adduction
innervation: CN III
Inferior oblique origin, insertion, action (primary and secondary), and innervation
Origin: maxillary bone
Insertion: inferior, posterior, lateral globe
Action: primary - extorsion, secondary - elevation and abduction
Innervation: CN III
What position can you isolate single actions of EOMs?
Secondary position
Secondary position?
Rotations around the horizontal (z-axis) or vertical (x-axis) axis
True or False: all insertion points of rectus muscles are anterior to the equator
True
Lateral rectus origin, insertion, action, and innervation?
Origin: tendinous ring and sphenoid (greater wing)
Insertion: anterior part of globe
Action: abduction
Innervation: CN VI
Join rectus muscles to orbital walls and Tenon's capsule?
Connective tissue sleeves/pulleys
What two muscles are isolated in the adducted position?
Superior oblique and Inferior oblique
Tertiary position?
Rotations around both horizontal (z-axis) and vertical (x-axis) axes
Medial rectus
Superior rectus origin, insertion, action (primary and secondary), innervation
Origin: tendinous ring and ON sheath
Insertion: anterior part of globe
Action: primary - elevation, secondary - adduction, intorsion
Innervation: CN III
Helps refine position, coordination of binocular eye movements?
Sleeves with smooth muscle attachments
Superior rectus and Inferior rectus
What are the four rectus muscles?
Superior
Inferior
Lateral
Medial
What two muscle origins are also attached to the dural sheath of the optic nerve?
Medial rectus and superior rectus
Inferior rectus origin, insertion, action (primary and secondary), and innervation
Origin: tendinous ring
Insertion: anterior part of globe
Action: primary - depression, secondary - adduction, extorsion
Innervation: CN III
During a clinical assessment, what is the name for eye movements?
Ocular motilities
What describes reciprocal innervation, contraction of one muscle occurs with equal relaxation of it antagoni?
Sherrington's law