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Anatomy · Head and neck: extraocular muscles
Sample itemA man has a complete right oculomotor nerve palsy from a posterior communicating artery aneurysm. Which extraocular muscles of the right eye still function?
Original practice item, not a recalled exam question. Nothing here is recorded.
The answer and the reasoning
A. Lateral rectus and superior oblique
Lateral rectus is supplied by the abducens nerve (LR6) and superior oblique by the trochlear nerve (SO4); all remaining extraocular muscles are supplied by the oculomotor nerve. With a complete oculomotor palsy the eye lies down and out, with ptosis and a dilated pupil, but abduction and intorsion on downward gaze remain.
Option by option
A. Lateral rectus and superior oblique (correct)
Correct. These two are not supplied by the oculomotor nerve.
B. Superior rectus and lateral rectus
Superior rectus is supplied by the oculomotor nerve and is paralysed.
C. Lateral rectus and medial rectus
Medial rectus is supplied by the oculomotor nerve and is paralysed.
D. Superior oblique and inferior oblique
Inferior oblique is supplied by the oculomotor nerve and is paralysed.
Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.
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