Dnb neurosurgery Q21-

Neuro 1-4


Q 21 Most common site of Optic nerve injury
A. Intra-orbital
B. Intra-canalicular
C. Intra-meatal
D. Intracranial

Q22. Le-forte fracture  is for
A. Facial skeleton
B. Lower limb bone
C. Spinal injury
D. Pelvis fracture

Q23. Best predictor in the GCS

A. Eye opening
B. Motor response
C. Verbal response
D. All


Ans. 21 B
Ref. Clinical Neurophthalmology, 431

Most common site is bony optic canal (intra canalicular( followed by intracranial optic nerve. Next is intra orbital.

The diagram below shows the parts of optic nerve

Entry of central retinal artery

Lesions anterior to central retinal artery insertion : Vision loss + Abnormalities in retinal circulation

Lesions post to central retinal artery insertion : mostly visual field changes

22.) A

Facial skeleton

Le fort classified these fractures  on the basis of pattern he got by applying force on cadavers. 

The question has been discussed here 

23) B, Motor response

Motor score is the best predictor of neurological outcome.

The m component of the GCS,  is not only linearly related to survival, but preserves almost all the predictive power of the GCS