Eye. and Eye movements Flashcards
what are the bones in the bony. orbit
- Frontal bone
- Sphenoidal bone
- Zygomatic bone
- Maxillary bone
- Ethmoid bone
- Lacrimal bone
The optic canal carries
- optic nerve (CN II)
2. opthalmic artery.
superior orbital fissure carries
CN III, IV, V1, 6,
ophthalmic veins.
inferior orbital fissure
maxillary nerve (as it changes into infraorbital N), infraorbital artery, zygomatic nerve (branch of V2)
Sinus and location
- Frontal sinus: superior and medial to the orbit
- Ethmoid sinus: medial to orbit
- Maxillary sinus: inferior to orbit
- Sphenoid sinus: medial to orbit, but posterior
what is a blow out fracture and what. bone is usually “blown out”?
the medial and inferior walls of the orbit are THIN AS FUCC.
a punch to the eye can cause things to prolapse through the broken maxillary bone (inferior wall) and protrude into the maxillary sinus. this can also send blood into the ethmoid sinus, located behind the zygomatic bone.
blow out fracture can cause what
diplopia (eyes not lining up)
globe ptosis (eyeball fall thru sinus)
exopthalmos (protrusion of eyeball)
What does the LPS do?
lift up eyelids
what. is the position of our eyeballs?
medial walls of orbit are parallel, however, the lateral walls are approximately at a right angle.
thus, the axes of the orbit diverge at 45 degrees, while the optical axes (axis of gaze) are parell
what are the movement of the pupil and what. is their axis
abduction, adduction in vertical axis.
Elevate or depress. in horizontal axis.
Intorsion (medial rotation) or extorsion (lateral rotation) in the AP axis
Levator palpebrae M.
Action:
I:
Levator palpebrae opens the EYELID and is innervated by oculomotor (CN III).
Medial rectus M.
I
Oculomotor N (CNIII)
lateral rectus M.
I
Abducens (CNVI)
superior rectus m
action
I
look up and medially Oculomotor N (CNIII)
inferior rectus m
action
I
look down and medially Oculomotor N (CNIII)
Superior oblique M.
action
I:
down and out and intorsion (medially rotate)
Trochlear N (CNIV)
inferior oblique m.
action
I:
Up and out and lateral rotates (extortion)
Oculomotor N
The obliques are abductors (LOOK OUT) due to their
insertion on the posterior surface of the eye.
what m muscles help us look to the left
Lateral rectus of left eye
Medial rectus of right eye
what m help us look straight down
superior oblique and inferior rectus both eyes
what muscles help us look straigt up
superior rectus and inferior oblique of both eyes
what m help us look to your left upper corner
L eye: inferior oblique
R: superior rectus
can m perform function when visual gaze is perpendicular. to the direction of the m fiber
no. they are trapped
how. do we. test. superior rectus m?
look up. and out
how do we test inferior oblique
look up and in
how do we test super oblique
look down and in
YOU ARE. JUST Changing THE LAST PART:
M WILL CONTINUE TO MOVE UP AND DOWN AS BEFORE
How to test lateral rectus
look out
what are the branches of CN V1: ophthalmic N
- Lacrimal N
- Frontal N.
Supratrochlear N
Supraorbital N - Nasociliary
A. Infratrochlear N (not on list)
B. Long ciliary N (NOL)
C. Anterior ethmoidal N (NOL)
D. Posterior ethmoidal N
E. Sensory root of the ciliary ganglion
Also associated with the visceral motor
component of the oculomotor nerve. Short ciliary N will then come off ciliary ganglion
What does the short ciliary N do?
- afferent fibers to cornea
2. parasympathetics to the iris and ciliary body
Lacrimal gland innervations
Lacrimal N does GENERAL sensation to the lacrimal gland.
Facial N: parasympathetics
Innvervation to the extra ocular m is done by?
- Oculomotor (CN3)
- Trochlear (CN4)
- Abducens (CN6)
path of oculomotor N
Comes from the midbrain and carries parasympathetic fibers.
Travels next to the diaphragma sellae in the cavernous sinus before it travels through the superior orbital fissure.
path of trochlear N
Comes out from the midbrain as well, but on the dorsal aspect - causing it to have a really long cranial path.
This enters the dura near the tentorium cerebelli.
Also goes lateral to cavernous sinus and the superior orbital fissure.
Trochlear nerve innervates SO m.
Path of abducens
- Nucleus: in pons.
- Leaves pontine medullary junction
- Enters the dura near the clivus, then runs THROUGH the cavernous sinus next to the internal carotid artery.
- superior orbital fissure.
Branches of oculomotor N
- Superior division of the oculomotor N: innervates LPS, SR
2. Inferior division of oculomotor N: innervates IO, IR, MR
What does NOT go through the common tendinous ring?
- Frontal N. (CN V1)
- Lacrimal N (CN V1)
- Trochlear N (CN 4)
4 and 5 STAY OUTSIDE