pedunculi

Pedunculus (plural pedunculi) is a Latin term used in anatomy and botany to denote a stalk-like structure that attaches a part to the rest of an organism or supports an inflorescence. In botany, the peduncle is the stalk bearing a flower or an inflorescence; the stalk of an individual flower is a pedicel. In human anatomy and zoology, the term is used for slender stalks that connect organs or brain structures.

In the nervous system, pedunculi refer to major fiber tracts that link regions of the brain. The cerebral peduncles (pedunculi cerebri) are prominent bundles on the ventral midbrain that connect the cerebrum to the brainstem and carry descending motor fibers, including corticospinal and corticobulbar tracts. The two pedunculi form part of the pathway conveying voluntary motor signals from the cortex to the brainstem and spinal cord.

The cerebellar peduncles (pedunculi cerebellares) connect the cerebellum with the brainstem. The superior cerebellar peduncle primarily carries information from the cerebellum to the midbrain, the middle peduncle communicates with the pons, and the inferior peduncle links the cerebellum with the medulla and spinal cord. Together they transmit afferent and efferent signals that coordinate balance and fine motor control.

Etymology and usage: the term derives from Latin pedunculus, a diminutive of pes, meaning “little foot.” The classical plural is pedunculi, though English usage often favors peduncle(s).