Subacute combined degeneration of the spinal cord occurs in individuals deficient in vitamin B12. This deficiency predominantly affects the dorsal column pathways and the lateral corticospinal tracts. Clinically, the patients present with a subacute to chronic weakness, paresthesias, and ataxia. Over time, they can develop spasticity because of involvement of the corticospinal tracts, hence presenting as a myelopathy. As opposed to a typical myelopathy, the reflexes are often diminished or absent due to a coexisting peripheral neuropathy, but plantar responses are extensor. Overall, the most common neurological manifestation of B12 deficiency is a peripheral polyneuropathy.