EOM Flashcards
Muscle cone
Superior
inferior
lateral
medial rectus
all originate from common annulus of zinn
Spiral of Tillaux
The rests muscles pass through the tenons capsule and insert into the sclera
Distance from edge of the cornea to the insertion of the muscle
Tenons Capsule
Tough membrane envelope in which the eyeball moves
fuses posteriorly with the optic nerve sheath and anteriorly with the inter muscular septum
Thin and flexible
Medial rectus
short and strong
Starts on the upper and lower limb of the common tendous ring and the optic nerve sheath
Runs forward, along a vertical line and inserts on the inside of the eye
Innervated by CN III
adducts
Cranial nerve III
From the back of the brain, through the superior orbital fissure along the underside of the muscle and inserts inside the muscle cone.
Lateral Rectus
Starts on the upper and lower limb of the common tendous ring and a process of the greater wing of the sphenoid bone. Innervated by cranial nerve 6 which enters the muscle on the medial surface.
abducts
Superior rectus
originates from the superior limb of the tendons ring and optic nerve sheath.
It passes forward underneath the elevator, the two sheath are connected resulting in coordinated movements. The lavatory. muscle sits on top which moves the lid.
frontal nerve sits on top of the sup r and lev.
the nasocillary nerve and ophthalmic artery run below.
Innervated by CN III
Inferior rectus
Originates from the lower region of common tendons ring
innervated by the lower division of CN III
Superior oblique
originates from the lesser wing of the sphenoid bone
Longest and thinnest EOM
INNERVATION by CN 4, the trochlear nerve posterior to the orbit
has a direct connection with the orbital wall.
oblique pushes the eye
Action of the Sup oblique
depression ,abduction and intorsion
Inferior Oblique
Originates behind lacrimal fossa
Only EOM originating from the front of the orbit
Extortion, elevation , and abduction
Lower CN III
Herrings Law
the eyes need to move equally and simultaneously
Sherringtons Law
as one muscle contracts,
its opposite muscle must relax
CN VI
innervates the lat rectus muscle
CN III
Innervates the leaver palpable, sup. rectus, med. rectus, inferior rectus and inferior oblique muscles.
