Column of Clarke

The dorsal nucleus (column of Clarke, Clarke's columns, posterior thoracic nucleus) occupies the medial part of the base of the posterior column, and appears on the transverse section as a well-defined oval area.

It begins below at the level of the second or third lumbar nerve, and reaches its maximum size opposite the twelfth thoracic nerve.

Above the level of the ninth thoracic nerve its size diminishes, and the column ends opposite the last cervical or first thoracic nerve.

It is represented, however, in the other regions by scattered cells, which become aggregated to form a cervical nucleus opposite the third cervical nerve, and a sacral nucleus in the middle and lower part of the sacral region.

Its cells are of medium size, and of an oval or pyriform shape; their axons pass into the peripheral part of the lateral funiculus of the same side, and there ascend, probably in dorsal spinocerebellar (direct cerebellar) fasciculus.