Glossary

Antagonist: The antagonist muscle relaxes or lengthens while the agonist muscle contracts and is responsible for returning the body part to its anatomic position.

Antibody: Antibodies are proteins produced by the body’s immune system to fight foreign invaders, such as bacteria, allergens, or even transplanted tissue.

Botulinum toxin (BTX): Botulinum toxin is a substance produced by the bacterium Clostridium botulinum. Used in tiny doses, injections of botulinum toxin block the release of a chemical called acetylcholine at a neuromuscular junction. By interfering with nerve impulses, it causes paralysis of muscles.

Bronchospasm: Bronchospasm results when the bands of muscles around the airway (the bronchus) tighten, and limit the flow of air into and out of the lungs.

Carpal tunnel syndrome: Carpal tunnel syndrome occurs when pressure on the median nerve (which runs from the forearm into the hand through a rigid “channel” at the wrist) causes burning, tingling, or itching numbness in the palm of the hand and the fingers, especially the thumb and the index and middle fingers.

Catheter: A catheter is a thin, flexible, silicone tube inserted into the body to transport fluids into or out of the body.

Cerebral palsy: Cerebral palsy is caused by a lack of oxygen to the brain before, during or after birth. People with cerebral palsy have a combination of spasticity, uncoordinated movements, and difficulty with balance.

Chemodenervation: Chemodenervation is an interruption of messages sent between nerves and muscles by administration of a chemical substance, such as botulinum toxin (BTX). For example, injections of BTX into muscles produce local relaxation of treated muscles by slowing down the release of acetylcholine, a neurotransmitter that is present at the junctions of nerve and muscle cells and that regulates the delivery of messages from nerve cells to muscle fibers.

Clasped knife phenomenon: The examiner who is passively moving a spastic limb quickly through its range of motion feels constant resistance to movement and suddenly the limb feels as if it “lets go.”

Clonus: Clonus is a particular form of spasticity that occurs in response to a rapid stretching of a muscle, most often in the knee or foot. The response is a rapid rhythmic movement that may continue as long as the muscle is stretched or may gradually lessen.

Co-contraction: Co-contraction occurs when both the agonist and the antagonist muscles contract at the same time.

Cortex: The cortex is the outer layer of the brain. It is contains areas that are responsible for controlling movement (the motor cortex) and sensations (sensory cortex).

Counterstimulant: A counterstimulant is a stimulus that acts to oppose an unpleasant stimulus. For example, in people with pain, a mild vibration may be used as a stimulation to counter the sensation of pain.

Cubital tunnel syndrome: Cubital tunnel syndrome occurs when pressure on the ulnar nerve (which lies in a “channel” behind the funny bone) causes numbness and tingling in the ring and small fingers of the hand.

Denervate: To denervate tissue is to deprive of it of its nerve supply.

Electrical stimulation: Electrical stimulation is a technique in which a small electrical charge is applied to a muscle to counteract spasticity or another stimulus. Electrical stimulation can also be used to test reflexes or muscle activity.

Electromyography: Electromyography is a test that records the electrical responses of skeletal muscles while at rest and during voluntary action and electrical stimulation. During this test, a small needle is inserted into a muscle or a sensor is used to record the level of activity.

Encephalitis: Encephalitis is an inflammation (or swelling) of the brain.

Equinovarus: Equino, meaning horse, and varus, meaning to turn inward, denotes a disorder in which contracture of the calf muscles pulls the foot downward to point the toes with the heel elevated and turned inward toward the body so that the person walks on the side of his or her foot with the toes pointed down and the heel elevated. This is also known as club foot.

Flaccid: A flaccid muscle is lacking in strength or firmness.

Heterotopic ossification: Heterotopic ossification is an abnormal formation of bone tissue within the soft tissues outside of the bones.

Lumbar puncture: In a lumbar puncture, a special needle is inserted into the lumbar (lower) region of the back between two vertebrae into the spinal column.

Meningitis: Meningitis is an inflammation (or swelling) of the membrane that covers the brain and spinal cord. This membrane is called the meninges and is made up of three layers of tissue.

Multiple sclerosis (MS): MS is a disease that affects the brain and spinal cord (the central nervous system) and the nerves of the eyes. A fatty tissue called myelin coats and protects the nerve fibers of the central nervous system. The myelin helps nerve fibers send and receive signals. When the myelin is destroyed, as happens in MS, scar tissue forms. This scar tissue is called sclerosis, literally meaning harden. As more and more sclerotic or hardened areas develop on the nerves, the nerves are less able to properly send signals, and the nerves themselves may be damaged or destroyed.

Myelogram: A myelogram is a procedure that creates a visual image of the spinal cord. A dye is injected into the spinal canal, and a traditional X-ray or computed tomography scan is used to capture the picture.

Phenol: Phenol, also known as carbolic acid, is a poisonous white soluble crystalline acid made from benzene; it is used in manufacturing and as a strong disinfectant and antiseptic.

Proprioception: Proprioception, or the sense of one’s own body in space, arises from nerve terminals in the muscles, joints, and tendons that send information to the brain about movement and the position of the body. This information allows the brain to know how much a muscle is stretching and how a joint is bending, as well as where the parts of the body are in relationship to each other.

Reciprocal inhibition: To create movement, a muscle contracts (the agonist). At the same time, its opposing muscle (the antagonist) is usually forced to relax. This is called reciprocal inhibition because the antagonist muscles are inhibited or prevented from contracting.

Reflex: A reflex is a movement that is performed involuntarily when a sensory nerve is stimulated, sending a signal to the spinal cord, which then signals a muscle to contract.

Rigidity: Rigid muscles are stiff or tense, making them difficult to move.

Selective dorsal rhizotomy (SDR): From the Greek words, rhizo, meaning root, and tome, meaning to cut, a rhizotomy is a surgical procedure in which cranial or spinal nerve roots are cut; the operation is performed to relieve intractable pain (anterior root rhizotomy) or to stop severe muscle spasms (posterior root rhizotomy).

Spastic catch: To the examiner who is passively moving a limb quickly through its range of motion, a spastic catch feels like a sudden resistance to movement.

Spinal column: The spinal column, also known as the vertebral column, is alternating layers of spongy tissue called discs and 33 bones called vertebrae, which encircle and protect the spinal cord and support the body and allow for movement.

Stroke: A stroke is a sudden loss of blood supply to an area of the brain because a blood vessel either breaks or becomes blocked. Other terms for stroke are brain attack and cerebrovascular accident.

Thalamus: The thalamus is an area of the brain consisting of two relatively large masses of gray matter. The thalamus relays information from most sensory organs to the outer region of the cerebrum or cerebral cortex; receives and processes messages from the body concerning heat, cold, pain, pressure, and touch; and influences motor activity of the cerebral cortex.

Thecal space: The thecal space is a thin, fluid-filled, multilayered membrane that covers the brain and spinal cord. The membrane, called the meninges, is made up of three layers of tissue called the dura, arachnoid and pia mater. Literally meaning hard mother, the dura mater is the outermost and toughest of the three membranes. The nerve roots and a clear fluid called the cerebrospinal fluid are also found within the thecal sac. This fluid protects the nerve roots and supplies nutrients to the spinal cord.

Tibial nerve: The tibial nerve is part of the sciatic nerve, which runs from the spinal cord to the calf and foot. The tibial nerve fibers begin in the lumbar and sacral parts of the spinal cord (L4 to S2). They send motor and sensory signals to parts of the calf and foot.

Traumatic brain injuries: A strong blow to the head or severe shaking of the head, particularly in babies, can cause traumatic brain injury. A closed head injury, meaning that the skull is not opened, happens when something hard hits the head or when the head hits something hard (for example, when a person’s head hits the pavement when he or she is thrown out of a car in an accident). In a penetrating closed head injury, the skull is opened and the object enters the skull and punctures the brain. A traumatic brain injury can cause a concussion, or bruising of the brain, or even coma or death.