Damage to the corticospinal system after brain injury interferes with activities of daily living, mobility, and communication. The chief cause of this interference has to do with impairment to produce and regulate voluntary movement accompanied by the presence of spasticity. This review advocates that the evaluation of spasticity should focus on 3 issues: (1) identifying the clinical pattern of motor dysfunction and its source; (2) identifying the patient's ability to control muscles involved in the clinical pattern; and (3) the differential role of muscle stiffness and contracture as it relates to the functional problem. We have identified and described 6 clinical patterns of motor dysfunction affecting the lower limbs during gait, found in patients with traumatic brain injury and residual from upper motor neuron lesions. We have presented the use of dynamic electromyography to identify the voluntary and spastic characteristics of individual muscles in gait and the use of anesthetic nerve blocks to identify properties of stiffness and contracture in particular muscle groups. Treatment algorithms for these problems include identification of the muscles that contribute to the deformity across a joint; the stage of patient recovery; and most important, the clinical goals applicable to the patient. The treatment strategies based on the algorithm included in this article were focused on the use of chemodenervation of targeted muscles, neuro-orthopedic surgery, and other therapeutic strategies.