EXTRAOCULAR MUSCLES

Question 1

WHAT ARE THE EXTRAOCULAR MUSCLES

Answer 1

VOLUNTARY
4 recti- superior, inferior, medial &lateral
2 oblique- superior, inferior
Levator palpebrae superioris
INVOLUNTARY- 
superior tarsal
inferior tarsal 
orbitalis

Question 2

WHAT ARE THE EXTRAOCULAR MUSCLES

Answer 2

VOLUNTARY
4 recti- superior, inferior, medial &lateral
2 oblique- superior, inferior
Levator palpebrae superioris
INVOLUNTARY- 
superior tarsal
inferior tarsal 
orbitalis

Question 3

ORIGIN AND INSERTION

Answer 3

ORIGIN- all recti muscles originate from corresponding margins of Annulus of Zinn/ common tendinous ring
INSERTION- into the sclera in front of the equator of the eyeball, distance of the insertion from limbus-
SR-8mm
LR-7mm
IR-6mm
MR-5mm

SO- origin- from the body of the sphenoid bone(orbital surface)
IO- from the floor of orbit( orbital part of maxilla)
INSERTION- into sclera behing equator of eyeball

Question 4

NERVE SUPPLY

Answer 4

SO- trochlear .N
LR- Abducent.N
LPS, SR- Superior division of occulomotor
IR, MR, IO- inferior division of occulomotor

Question 5

ACTION

Answer 5

Elevation- SR, IO
depression- IR, SO
Adduction-MR
Abduction-LR
Intorsion- SR, SO
Extorsion-IR, IO

Question 6

APPLIED

Answer 6

1. Ptosis
2. Medial squint
3. lateral squint
4. Injury to occulomotor nerve

Question 7

LEVATOR PALPEBRAE SUPERIORIS

Answer 7

ORIGIN- From lesser body of sphenoid
Insertion- into upper eyelid
Nerve supply- occulomotor nerve
Action- elevation of upper eyelid
APPLIED
Ptosis- injury to occulomotor nerve, paralysis of LPS, Drooping of eyelid due to inability to elevate
Partial ptosis- lesion of cervical sympathetic chain affects only smooth muscle part.