8.2.2 Anatomical Actions of Extra-Ocular Eye Muscles Flashcards
What is the insertion of superior rectus?
Inserts obliquely into superior anterolateral surface of globe
What is the action of the superior rectus?
Elevation (most powerful elevator when eye is positioned laterally)
Slightly adducts
Slightly intorts
What is the insertion of the inferior rectus?
Inserts obliquely into anteroinferior surface of globe
What is the action of inferior rectus?
Depress (most powerful depressor when eye is positioned laterally)
Slightly adducts
Slight extorts
What is the insertion of the superior oblique?
Arises from apex of orbit, passes through trochlea pulley, inserts into superior-posterior aspect of globe
What is the action of superior oblique?
Intort
Depress (most powerful depressor when eye is positioned medially)
Slightly abducts
What is the insertion of inferior oblique?
Arises from anteromedial surface of floor of orbit, inserts into infero-posterior aspect of globe
What is the action of inferior oblique?
Extort
Elevate (more powerful when eye is positioned medially)
Slightly abducts
Which EO muscles elevate the eye?
Superior rectus
Inferior oblique
Which EO muscles depress the eye?
Inferior rectus
Superior oblique
Which EO muscles are stronger elevators and depressors when the eye is adducted?
Elevator- inferior oblique
Depressor- superior oblique
Role is to abduct, therefore more tension when complete opposite direction
Which EO muscles are stronger elevators and depressors of the eye in the abducted position?
Superior rectus
Inferior rectus
How can we use resting gaze to determine muscle weakness?
Gaze should be forward and central, if the eye is pulled in one direction it is not be balanced by its antagonist properly, so there must be a weakness in the antagonist muscle
What is it called when a muscle is no longer antagonised?
Strabismus (squint) due to actions of remaining working muscles
