What structure connects the two lobes of the thalamus?

• A. Massa intermedia
• B. Pineal gland
• C. Hypothalamus
• D. Cerebral aqueduct

Answer: (A)

The structure that bridges the two thalami is the massa intermedia, also called the interthalamic adhesion. It is a thin band of gray matter that sits in the roof of the third ventricle and spans the midline to connect the left and right thalamic lobes. Its presence varies among individuals; some people have a prominent adhesion, while others have it reduced or absent.

The other options don’t fit because the pineal gland sits near the midline but is a secretory structure, not a bridge between the thalami. The hypothalamus lies below the thalamus as part of the diencephalon but does not connect the two thalami. The cerebral aqueduct runs between the third and fourth ventricles, serving as a CSF conduit rather than a connecting bridge between the thalami.