The posterior thoracic nucleus, (Clarke's column, column of Clarke, dorsal nucleus, nucleus dorsalis of Clarke) is a group of interneurons found in the medial part of lamina VII, also known as the intermediate zone, of the spinal cord. It is mainly located from the cervical vertebra C8 to lumbar L3-L4 levels and is an important structure for proprioception of the lower limb.2° (Spinomesencephalic tract → Superior colliculus of Midbrain tectum) The posterior thoracic nucleus, (Clarke's column, column of Clarke, dorsal nucleus, nucleus dorsalis of Clarke) is a group of interneurons found in the medial part of lamina VII, also known as the intermediate zone, of the spinal cord. It is mainly located from the cervical vertebra C8 to lumbar L3-L4 levels and is an important structure for proprioception of the lower limb. It occupies the medial part of the base of the posterior grey column and appears on the transverse section as a well-defined oval area. It begins caudally 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 eight thoracic nerve its size diminishes, and the column ends opposite the last cervical or first thoracic nerve.