A cisternal puncture is performed to obtain CSF when lumbar puncture fails. The needle is introduced between the atlas and the occipital bone into the largest subarachnoid cistern, which lies between:

• A The two frontal lobes above the optic chiasm
• B The cerebellar hemispheres below the vermis
• C The cerebral peduncles and the floor of the third ventricle
• D The posteroinferior surface of the cerebellum and the dorsal surface of the medulla ✓

Explanation

The cerebellomedullary cistern (cisterna magna) is the largest of the subarachnoid cisterns, lying between the posteroinferior cerebellar surface and the dorsal medulla, continuous below with the spinal subarachnoid space. It receives CSF from the fourth ventricle via the median aperture (foramen of Magendie). The interpeduncular cistern lies between the cerebral peduncles, and the quadrigeminal cistern lies behind the colliculi.

Reference: Gray's Anatomy, 42nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.