Extraocular Muscles Flashcards
list extraocular muscles
medial/lateral rectus, superior/inferior rectus, superior/inferior oblique
lateral rectus action
abduction
lateral rectus innervation
abducens (VI)
medial rectus action
adduction
medial rectus innervation
oculomotor (III)
superior rectus action
elevation and adduction
superior rectus innervation
oculomotor (III)
inferior rectus action
depression and adduction
inferior rectus innervation
oculomotor (III)
superior oblique action
depression and abduction
superior oblique innervation
trochlear (IV)
inferior oblique action
elevation and abduction
inferior oblique innervation
oculomotor (III)
action to test lateral rectus
look lateral
action to test medial rectus
look medial
action to test superior rectus
look lateral, then up
action to test inferior rectus
look lateral, then down
action to test inferior oblique
look medial, then up
action to test superior oblique
look medial, then down
oculomotor nerve injury characteristics
affected eye will be “down and out,” ptosis, mydriasis
explain oculomotor nerve injury characteristics
only trochlear (superior oblique) and abducens (abduction) will be functioning, causing the eye to drift inferiorly and laterally
trochlear nerve injury characteristics
affected eye will drift upward, mild adduction, with worsening symptoms on looking down. Looking down and out causes diplopia, and pt tilts head to unaffected side
explain trochlear nerve injury characteristics
the superior oblique will not work, so the ability of the eye to look downward will be diminished
abducens nerve injury characteristics
affected eye will drift medially
explain abducens nerve injury characteristics
the lateral rectus will not work, so eye cannot abduct and will adduct instead
eyelid muscle innervated by CN III
levator palpebrae superioris
esotropia
adducted eye at rest
strabismus
weakness of eye muscle(s)
