Many staining techniques have been used to study the anatomy of Onuf's nucleus. The Nissl method was commonly used as well as myelin sheath stains and silver stains. Use of the K-B staining method showed that Onuf's nucleus appears clear due to the presence of many vertically arranged unmyelinated fibers. The sizes of the cells in Onuf's nucleus are small in comparison to other lateral group cells. The neurons in Onuf's nucleus are motoneurons, and like most motoneurons they are characterized by their mulipolarity and large Nissl bodies.