37 Questions
What is the primary action of the Superior Rectus muscle?
elevation
What is the tertiary action of the Inferior Rectus muscle?
adduction
In which direction do the Superior and Inferior Rectus muscles lie in the primary position?
At a 23-degree angle relative to the visual axis
What is the primary action of the Superior Oblique muscle?
intortion
Which muscles are responsible for elevation and depression when the eye is in adduction?
SO and IO
What is the secondary action of the Oblique muscles?
vertical movement
What happens to the Superior Rectus muscle when the eye is fully abducted?
It becomes a pure elevator
What is the tertiary action of the Superior Oblique muscle?
abduction
What occurs during binocular movements, like head tilt to the right?
Equal and simultaneous innervation to the yoke muscles
What is the name of the law that states that increased contraction of an agonist muscle is associated with diminished contractile activity of its antagonist muscle?
Sherrington's Law of Reciprocal Innervation
What is the name of the nerve that innervates the superior oblique muscle?
Trochlear nerve
Which muscle is responsible for adduction and is the largest and strongest of the oculomotor muscles?
Medial rectus
During convergence, which muscles experience increased activity?
RMR and LMR
What is the vascular supply of the medial and inferior rectus muscles?
Inferior muscular artery branch of the ophthalmic artery
What is the result of head tilt to the right on the muscle groups?
Muscle group for incyclotorsion of the OD and excyclotorsion of the OS contract, while the muscle group for excyclotorsion of the OD and incyclotorsion of the OS relax
What is the speed range for following objects during the recording of SAFE or FESA?
up to 400 degrees/sec
When the eye is fully adducted, which muscle is responsible for elevating the eye?
Inferior oblique
What is the angle of the plane in which the SO and IO lie relative to the primary gaze?
51 degrees
What is the purpose of the Saccades Test?
To test for voluntary saccadic movement
What is the purpose of the Broad H Test?
To assess the patient's ability to perform conjugate eye movements
What is the distance between the two targets in the Saccades Test?
20 cm
What is the direction of the circles moved during the Pursuits Test?
Two clockwise and two counterclockwise circles
Which type of eye movement is mediated by the parieto-occipital junction (area 19)?
Pursuits
What is the term for the field in which a certain muscle has the greatest action?
Field of action
What is a symptom of Isolated 3rd Cranial Nerve Palsy?
Diplopia with both eyes open, disappears closing one eye
What is a sign of Isolated 3rd Cranial Nerve Palsy?
Binocular horizontal diplopia
Which muscle is responsible for depressing the eye when it is fully adducted?
Superior oblique
What is a possible outcome if the target is taken to the extreme limits during the SAFE or FESA test?
Endpoint nystagmus
What is the term for the ability of the eyes to move together in the same direction?
Conjugate movement
What is the term for fast eye movements?
Saccades
Which of the following symptoms is NOT associated with an aneurysm affecting the Posterior Communicating Artery?
Pain in the arm
What is the characteristic head tilt in a patient with a 4th Cranial Nerve Palsy?
Towards the contralateral shoulder
What is the primary reason for a patient with a 4th Cranial Nerve Palsy to experience diplopia?
Binocular vertical diplopia
Which of the following causes of 4th Cranial Nerve Palsy has a long course through the cranial vault?
Tumor
What is the characteristic change in hypertropia in a patient with a 4th Cranial Nerve Palsy?
Increases when looking towards the direction of the uninvolved eye
What is the primary reason for immediate medical evaluation in a patient with an aneurysm affecting the Posterior Communicating Artery?
Localized headache
Which of the following is a common vasculopathic cause of 4th Cranial Nerve Palsy?
Diabetes Mellitus
Test your understanding of oculogyric centers and their role in binocular movements, including simultaneous innervation and muscle contractions. Learn about Sherrington's Law of Reciprocal Innervation and how it applies to eye movements.
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