Orbit & Extraocular Muscle Anatomy – Hard MCQs
1. Which structure does NOT pass through the superior orbital fissure?
Oculomotor nerve
Trochlear nerve
Optic nerve
Abducens nerve
2. The weakest wall of the orbit is the:
Roof
Lateral wall
Medial wall
Posterior wall
3. Which muscle originates from the anterior part of the orbital floor?
Inferior rectus
Inferior oblique
Superior oblique
Medial rectus
4. The trochlea acts as a pulley for which muscle?
Inferior oblique
Superior rectus
Superior oblique
Lateral rectus
5. All rectus muscles originate from:
Lesser wing of sphenoid
Greater wing of sphenoid
Annulus of Zinn
Optic canal
6. Primary action of medial rectus muscle:
Abduction
Adduction
Elevation
Intorsion
7. Which nerve supplies the lateral rectus muscle?
Oculomotor
Trochlear
Trigeminal
Abducens
8. Levator palpebrae superioris is supplied by:
CN IV
CN VI
CN III
Sympathetic only
9. Inferior orbital fissure connects orbit to:
Middle cranial fossa
Anterior cranial fossa
Pterygopalatine fossa
Nasal cavity
10. Ophthalmic artery is a branch of:
External carotid
Internal carotid
Basilar artery
Vertebral artery
11. A patient cannot abduct his eye. Which muscle is paralyzed?
Medial rectus
Superior oblique
Lateral rectus
Inferior rectus
12. A blow-out fracture commonly traps which muscle?
Superior rectus
Inferior rectus
Medial rectus
Superior oblique
13. Vertical diplopia worse on looking down stairs suggests damage to:
Inferior oblique
Superior oblique
Inferior rectus
Medial rectus
14. Ptosis with dilated pupil indicates injury to:
CN IV
CN VI
Sympathetic nerve
CN III
15. Infection from ethmoid sinus spreads easily to orbit due to thin:
Orbital roof
Lamina papyracea
Zygomatic bone
Palatine bone
16. Eye deviated down and out with ptosis – nerve involved?
CN II
CN III
CN IV
CN VI
17. Loss of intorsion indicates paralysis of:
Inferior oblique
Superior oblique
Superior rectus
Inferior rectus
18. Cavernous sinus thrombosis most commonly affects which eye movement?
Elevation
Depression
Abduction
Adduction
19. Damage to inferior orbital fissure affects sensation over:
Upper eyelid
Forehead
Cheek
Scalp
20. Loss of eyelid elevation with preserved eye movements suggests injury to:
Müller’s muscle
Superior rectus
Inferior oblique
Lateral rectus
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