Registered Practical Nurse (RPN) Practice Test

Which anatomical structure separates the left and right hemispheres of the brain?

1. The corpus callosum

2. The longitudinal fissure

3. The central sulcus

4. The lateral sulcus

The correct answer is: The longitudinal fissure

The anatomical structure that separates the left and right hemispheres of the brain is the longitudinal fissure. This deep groove runs along the midline of the brain and divides it into the two hemispheres. The longitudinal fissure is significant not only because it creates a physical separation between the two hemispheres, but it also plays a crucial role in their functional specialization. Each hemisphere is responsible for different cognitive and motor functions, and the longitudinal fissure helps to delineate these areas. In contrast, the corpus callosum serves as the major neural pathway connecting the two hemispheres, allowing for communication and coordination between them, rather than separating them. The central sulcus is a prominent landmark that separates the frontal and parietal lobes of the brain, while the lateral sulcus separates the frontal and temporal lobes. Thus, while these structures are all important in brain anatomy, it is the longitudinal fissure that is responsible for dividing the left and right hemispheres.