Neurosurgery is a clinical specialty that diagnoses and treats illnesses that occur in the nervous system using surgical and medical methods. The nervous system is divided into the central nervous system and the peripheral nervous system, and while the central nervous system is composed of the brain and spinal cord surrounded by the spine, the peripheral nervous system includes all nerves that start out from the brain and spinal cord and head toward each organ, the muscles, skin etc. Clinically, neurosurgery deals largely with the brain and spinal cord. It deals with the treatment of disorders such as brain cancer, cerebrovascular disorders, facial spasms and trigeminal neuralgia, head trauma, epilepsy, congenital and developmental deformations. Meanwhile, spinal neurosurgery is a specialty that deals with treatment for illnesses such as spinal cancer, degenerative spinal diseases, lumbar disk hernia, cervical disk hernia, spinal injury, hand tremor and intractable pain.