An upper motor neuron syndrome often leads to the development of stereotypical patterns of deformity secondary to agonist muscle weakness, antagonist muscle spasticity and changes in the rheologic (stiffness) properties of spastic muscles. Identification of the spastic muscles that contribute to deformity across a joint allows therapeutic denervation to be implemented with the maximum likelihood of success. Identifying responsible muscles can be complex, since many muscles may cross the joint involved, and not all muscles with the potential to cause deformity will be spastic. Strategies including polyelectromyography and diagnostic blocks with local anesthetics can be used to test hypotheses regarding the deformity, providing information for more long-term denervation. In this review, we discuss frequently observed patterns of deformity associated with problematic spasticity, paresis, contracture, and impaired voluntary motor control.