Where it is
Inside the orbit, from the back of the orbit (common tendinous ring) to the sclera.
What it does
The lateral rectus is controlled by cranial nerve VI (abducens), the superior oblique by cranial nerve IV (trochlear) and the others by cranial nerve III (oculomotor). Mnemonic: LR6 SO4, the rest are 3.
Clinical relevance
- Damage to cranial nerve III causes a down-and-out eye, a dilated pupil and ptosis.
- Nystagmus or double vision can signal brainstem, cerebellar or drug-related problems.
Nursing focus
- Test the six cardinal fields of gaze by having the client follow your finger in an H pattern.