EOMs Physiology Flashcards
the two groups EOMs can be divided into & what they consist of
responsible for eye movement in different gazes → recti & oblique muscles
responsible for superior eyelid elevation → LPS, Muller’s, frontalis
what forms the basis for eye movements that result from their contraction
shape, size, & orientation of EOMs from origin to insertion
what must occur for accurate positioning of the visual world on the fovea
activity of all EOMs must be tightly coordinated
what do the oblique muscles control
adjustments involved in counteracting head movement
ductions & torsions are what kind of ocular movement
monocular
versions & vergences are what kind of ocular movements
binocular
primary, secondary, & tertiary action of medial rectus
adduction only
primary, secondary, & tertiary action of lateral rectus
abduction only
primary, secondary, & tertiary action of superior rectus
elevation, incyclotorsion, adduction
primary, secondary, & tertiary action of inferior rectus
depression, excyclotorsion, adduction
primary, secondary, & tertiary action of superior oblique
incyclotorsion, depression, abduction
primary, secondary, & tertiary action of inferior oblique
excyclotorsion, elevation, abduction
what are the 3 factors involved in mechanisms of EOMs action
cross-sectional area of muscle, length of muscle, arc of contact
explain cross-sectional area of muscle
muscle exerts force in proportion to their cross-sectional area
explain length of muscle
a normal 45-50 degrees amplitude of rotation → a 1mm change in muscle length is required in each direction;
sacrificing muscle length during resection reduces amplitude of rotation
