Also known as Goll's nucleus, the gracile nucleus is a massive cluster of nerve cells situated in the posterior or dorsal part of the medulla oblongata. It is grey in color and is surrounded by white matter. The gracile nucleus receives sensitive information (fine touch) from the middle thoracic and lower limbs, via the dorsal root ganglia neurons. Its nerve cells axons run up into the thalamus to establish connection there.
Below: Goll's nucleus (image taken from wikipedia)