The sulcus limitan marks the boundary between which plates?

The sulcus limitan marks the boundary between which plates?

• A. Basal and alar plates
• B. Ventral and dorsal plates
• C. Floor plate and root plate
• D. Dorsal columns and ventral columns

Answer: (A)

The sulcus limitans is a longitudinal groove in the developing neural tube that separates the dorsal sensory region from the ventral motor region. It marks the boundary between the alar plate on the back (dorsal) side, which gives rise to sensory structures, and the basal plate on the front (ventral) side, which gives rise to motor neurons. This division explains why the dorsal horns and associated sensory pathways come from the alar plate, while the ventral horns and motor outputs come from the basal plate. Other options don’t align with this boundary: the floor plate is a ventral midline structure involved in patterning signals, the root plate relates to motor nerve roots, and the dorsal vs ventral columns refer to white matter tracts rather than the plate boundaries.

The sulcus limitans is a longitudinal groove in the developing neural tube that separates the dorsal sensory region from the ventral motor region. It marks the boundary between the alar plate on the back (dorsal) side, which gives rise to sensory structures, and the basal plate on the front (ventral) side, which gives rise to motor neurons. This division explains why the dorsal horns and associated sensory pathways come from the alar plate, while the ventral horns and motor outputs come from the basal plate. Other options don’t align with this boundary: the floor plate is a ventral midline structure involved in patterning signals, the root plate relates to motor nerve roots, and the dorsal vs ventral columns refer to white matter tracts rather than the plate boundaries.