Question

Identify the marked structure in the image.

• A. Cerebrum
• B. Brain stem
• C. Corpus callosum
• D. Cerebellum

Hint:

Posterior cranial fossa, below the tentorium - the little brain.

Answer 1

The Correct Option is D

Step 1: The marked structure is the cerebellum, literally the "little brain". It is a central nervous system structure with a key role in motor control and coordination; cerebellar lesions present with motor signs such as ataxia.
Step 2: Location confirms the identity. The cerebellum lies at the back of the brain, immediately inferior to the occipital and temporal lobes, within the posterior cranial fossa.
Step 3: It is separated from the overlying occipital lobe by the tentorium cerebelli, a tough fold of dura mater. It lies posterior to the pons, separated from it by the fourth ventricle.
Step 4: These features make option (d) cerebellum correct. The cerebrum (a) is the large supratentorial mass, the brain stem (b) is anterior, and the corpus callosum (c) is the midline commissure connecting the hemispheres - none match the marked posterior-fossa structure.