Disorders that affect the brain, spinal cord, and nerves are called neurologic disorders.
Neurologic symptoms—symptoms caused by a disorder that affects part or all of the nervous system—can vary greatly because the nervous system controls so many different body functions. Symptoms can include all forms of pain, including headache Overview of Headache A headache is pain in any part of the head, including the scalp, upper neck, face, and interior of the head. Headaches are one of the most common reasons people visit a doctor. Headaches interfere... read more and back pain Low Back Pain Low back pain and neck pain are among the most common reasons for health care visits. The pain usually results from problems with the musculoskeletal system—most notably the spine, including... read more . Muscles, skin sensation, the special senses (vision, taste, smell, and hearing), and other senses depend on nerves to function normally. Thus, neurologic symptoms can include muscle weakness or lack of coordination, abnormal sensations in the skin, and disturbances of vision, taste, smell, and hearing.
Neurologic disorders can interfere with sleep, making a person anxious or excited at bedtime and thus tired and sleepy during the day.
Neurologic symptoms may be minor (such as a foot that has fallen asleep) or life threatening (such as coma due to stroke).
The characteristics and pattern of symptoms help doctors diagnose the neurologic disorder. Doctors also do a neurologic examination Neurologic Examination When a neurologic disorder is suspected, doctors usually evaluate all of the body systems during the physical examination, but they focus on the nervous system. Examination of the nervous system—the... read more , which can detect disorders of the brain, spinal cord, and nerves in other parts of the body (peripheral nerves).
Peripheral nerves Overview of the Peripheral Nervous System The peripheral nervous system refers to the parts of the nervous system that are outside the central nervous system, that is, those outside the brain and spinal cord. Thus, the peripheral nervous... read more include
The nerves that connect the head, face, eyes, nose, muscles, and ears to the brain (cranial nerves Overview of the Cranial Nerves Twelve pairs of nerves—the cranial nerves—lead directly from the brain to various parts of the head, neck, and trunk. Some of the cranial nerves are involved in the special senses (such as seeing... read more )
The nerves that connect the spinal cord to the rest of the body: 31 pairs of spinal nerves
Nerves that run throughout the body
Some peripheral nerves (sensory nerves) carry sensory information (about such things as pain, temperature, vibration, smells, and sounds) to the spinal cord and then to the brain. Others (motor nerves) carry impulses that control muscle movement from the brain through the spinal cord to the muscles. Still others (called the autonomic nerves Overview of the Autonomic Nervous System The autonomic nervous system regulates certain body processes, such as blood pressure and the rate of breathing. This system works automatically (autonomously), without a person’s conscious... read more ) carry information about the body and external environment to the internal organs, such as the blood vessels, stomach, intestine, liver, kidneys, and bladder. In response to this information, autonomic nerves stimulate or inhibit the organs they supply. These nerves work automatically (autonomously), without a person’s conscious effort.
If motor nerves are damaged, muscles may weaken or become paralyzed. If sensory nerves are damaged, abnormal sensations may be felt or sensation, sight, or another sense may be impaired or lost. If autonomic nerves are damaged, the organ they regulate may malfunction. For example, blood pressure may not increase as it normally does when a person stands, and the person may feel light-headed Dizziness or Light-Headedness When Standing Up In some people, particularly older people, blood pressure drops excessively when they sit or stand up (a condition called orthostatic or postural hypotension). Symptoms of faintness, light-headedness... read more .