Some causes of head tremors in humans are multiple sclerosis, stroke, brain injuries and neurodegenerative diseases, notes National Institute of Neurological Disorders and Stroke. Tremors are characterized by involuntary muscle movement; they are usually caused by neurological disorders in the brain.
Multiple sclerosis is a condition that affects the central nervous system which results in tremors, as well as numbness and blurred vision, states WebMD. Stroke occurs when blood flow to the brain is cut off, and tremors result from the trauma. Brain injuries from traumatic events, such as car accidents and injuries resulting from brain damage, are common causes of tremors due to resulting nerve damage. Neurodegenerative diseases result in the gradual degeneration of nerve cells. These diseases include Alzheimer's, Parkinson's and Huntington's disease.