Question:easy
According to the ISNT rule, what is the thinnest part of the neuro-retinal rim?
According to the ISNT rule, what is the thinnest part of the neuro-retinal rim?
Show Hint
ISNT goes thickest to thinnest; the last letter is the answer.
Updated On: Jun 24, 2026
- Inferior
- Superficial
- Temporal
- Medial
Show Solution
The Correct Option is C
Solution and Explanation
Step 1: Spell out the mnemonic. ISNT stands for Inferior, Superior, Nasal, Temporal, listed from the thickest to the thinnest segment of the normal neuro-retinal rim.
Step 2: Read off the answer. Because Temporal is the last letter, the rim is thinnest on the temporal side and thickest on the inferior side.
Step 3: Note the disease correlation. Glaucomatous damage disturbs this sequence, producing preferential thinning at the inferior and superior poles and a violation of the ISNT rule that helps diagnosis.
Step 4: Dismiss the wrong options. Inferior is the thickest region, and superficial and medial are not even part of the ISNT terminology, leaving temporal as the correct thinnest part.
\[\boxed{\text{Temporal}}\]
Step 2: Read off the answer. Because Temporal is the last letter, the rim is thinnest on the temporal side and thickest on the inferior side.
Step 3: Note the disease correlation. Glaucomatous damage disturbs this sequence, producing preferential thinning at the inferior and superior poles and a violation of the ISNT rule that helps diagnosis.
Step 4: Dismiss the wrong options. Inferior is the thickest region, and superficial and medial are not even part of the ISNT terminology, leaving temporal as the correct thinnest part.
\[\boxed{\text{Temporal}}\]
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