The nervous system has two distinct parts: the central nervous system (the brain and spinal cord) and the peripheral nervous system (the nerves outside the brain and spinal cord). The nervous system is an extraordinarily complex communication system that can send and receive voluminous amounts of information simultaneously. However, the system is vulnerable to diseases and injuries. From the brain come all thoughts, beliefs, memories, behaviors, and moods. The brain is the site of thinking and the control center for the rest of the body.
The peripheral nervous system consists of more than 100 billion nerve cells that run throughout the body like strings, making connections with the brain, other parts of the body, and often with each other. Peripheral nerves consist of bundles of nerve fibers. Nerves conduct impulses at different speeds depending on their diameter.
The spinal cord is a long, fragile tubelike structure that begins at the end of the brain stem and continues down almost to the bottom of the spine (spinal column). The spinal cord consists of nerves that carry both incoming and outgoing messages between the brain and the rest of the body. The spinal cord and meninges are contained in the spinal canal, which runs through the center of the spine. In most adults, the spine is composed of 26 vertebrae, which are the individual bones of the back. Just as the skull protects the brain, vertebrae protect the spinal cord.
A neurologic examination can detect disorders of the brain, spinal cord, and nerves. This examination can also help detect muscle disorders because muscle contraction depends on stimulation by a nerve. The two main components of a neurologic examination are the medical history and the physical examination (including mental status evaluation). If necessary, diagnostic procedures are performed to confirm the diagnosis or exclude other possible disorders.
A neurologic examination differs from a psychiatric examination, which focuses on a person's behavior. However, the two examinations overlap somewhat because abnormal behavior often provides clues about the brain's physical condition.
Common Neurological Disorders
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