Generation of a long process of a CNS neuron, that carries efferent (outgoing) action potentials from the cell body in the dorsal root ganglion towards target cells in the medulla. This axonal process is a member of those that make up the cuneatus tract, a group of axons that are from neurons involved in proprioception from the upper trunk and upper limb. [ http://purl.obolibrary.org/obo/go/references/0000021 GOC:cls GOC:dgh GOC:dph GOC:jid http://www.ncbi.nlm.nih.gov/pubmed/12867698 ]