Extraocular muscles Flashcards
The muscles connect to the globe ( along w their stiff tendons) at sites called the _
Insertion
The distance of insertion of rectus muscles from the corneal limbus are as follows: medial retus _ mm inferior _ mm lateral retus _ mm superior retus _mm
5.5, 6.5, 7, 7.7
The _ muscle originates from the nasal orbital wall behind the rim, passes under the inferior rectus, curves around the eye, and inserts under the lateral rectus posterior on the eye
Inferior oblique ( IO)
The _ muscle originates from the annulus of Zinn, passes through the trochlea ( pulley) on the nasal orbital rim, then under the superior rectus tendon to insert into the the sclera
Superior oblique( SO)
If the eye looks towards the nose ( nasally) it is called
Adduction
If the eye looks towards the ear ( temporally) it is called
Abduction
If the eye looks up it is called
Elevation
If the eye looks up it is called
Depression
__ refers to nasal rotation from the 12 o clock position
Incycloduction ( intorsion)
__ refers to temporal rotation from the 12 o clock position
Excycloduction ( extorison)
Contraction of the MR primary ( and only) action
Adduction
Contraction of the LR primary ( and only) action
Abduction
Contraction of the SR Primary action, secondary action, tertiary action
Elevation , adduction, incycloduction ( intorsion)
Contraction of the IR primary action, secondary action, tertiary action
Depression, adduction, excycloduction
Contraction of the SO primary action, secondary action, tertiary action
Incycloduction, depression, abduction
Contraction of the IO primary action, secondary action, tertiary action
Excycloduction, elevation , abduction
__ is when both eye turn towards the nose to look near
Convergence
_ is when both eyes turn away from the nose to look distance
Divergence
_ is when both eyes move in the same direction
Version
The extraocular muscles nerve innervation is
LR6, SO4, R3
All of the extraocular muscles except for the inferior oblique originate in the
Annulus of Zinn
