Question 1: Identify the structure shown below. (Recent NEET Pattern 2019)
- A. Fornix (Correct Answer)
- B. Corpus callosum
- C. Pineal gland
- D. Splenium
- E. Septum pellucidum
Explanation: ***Fornix***
- The arrow points to a C-shaped bundle of **nerve fibers** in the brain that acts as the primary efferent (output) pathway of the **hippocampus**, a crucial structure for memory.
- It is located inferior to the corpus callosum and its position in the image is consistent with the anatomical location of the fornix.
*Corpus callosum*
- The corpus callosum is a large, **C-shaped nerve fiber bundle** located beneath the cerebral cortex in the longitudinal fissure, connecting the left and right cerebral hemispheres.
- While visible in the image, the arrow specifically indicates the structure immediately beneath it, which is the fornix, not the corpus callosum itself.
*Pineal gland*
- The **pineal gland** is a small endocrine gland located in the epithalamus, near the center of the brain, behind the thalamus.
- Its position is medial and inferior to the structure indicated by the arrow.
*Splenium*
- The **splenium** is the posterior, thicker part of the **corpus callosum**, forming its most caudal end.
- The arrow points to a more anterior and inferior structure than the splenium.
*Septum pellucidum*
- The **septum pellucidum** is a thin, vertical membrane separating the anterior horns of the left and right lateral ventricles.
- It is located superior and anterior to the fornix, positioned between the corpus callosum above and the fornix below, which is different from the structure indicated by the arrow.
