Medical/Neurosurgical Glossary
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Sacroiliac Joint – A synovial joint formed between the medial surface of the ilium and the lateral aspect of the upper sacral vertebrae; a fibrous joint, comprising and surrounded by very strong ligamentous structures; major function is to transmit body weight, but also has some movement.

Sacro-Occipital Technique – Chiropractic diagnostic and treatment method said to involve analysis and correction of sacral and cranial distortions to improve circulation of cerebrospinal fluid. The degree of alleged correction obtained is monitored by checking leg length.

Sacrum – The lower portion of the spine which is below the low back and above the tail bone or the coccyx.  The sacrum attaches to the pelvis. It contains some of the lowest spinal nerves.  It is one of the bones most frequently fused by spinal surgeons.

Sagittal – Refers to an imaginary plane that makes a lengthwise cut and divides the body into right and left portions.

Saint Anthony’s Fire – A painful strep infection of the skin which can occur anywhere but is most common in the face.

Saline Solution -- This solution contains sodium chloride which mimics the plasma of the blood.

Sanctions - monetary fines imposed when a party violates the law; applies only to the California state system.

Scalenus Anticus Syndrome – Pain over the shoulder from compression of the nerves under this muscle.

Scapula – Commonly known as the shoulder blade.

Sciatica – An old word which means leg pain from a pinched nerve.  This is usually distinguished from lumbago, another old word which refers to back pain.

Scoliosis – A curvature of the spine which may be congenital (a birth defect) or acquired (degenerative, arthritic, or traumatic). 

Second opinion – there are several types of second opinions.  An employee may ask for a second opinion if he or she has questions regarding care.  A doctor may ask for a second opinion.  The insurance company can ask for second opinions at any time.  For spine problems a special second opinion system has been set up.  A state assigned doctor may be required to authorize certain spine operations before they can be scheduled.

Selective Block, Selective Nerve Block – This refers to an injection into the neck or back, like an epidural block, where the medication is delivered very precisely or selectively to just one or several damaged nerve roots.  X-ray machines are used to “see” the nerve roots.

Sepsis – A widespread infection of multiple parts of the body.  This usually begins in one place and spreads.  It is particularly common in very young people, very old people, people with AIDS, people with diabetes, or those on cancer chemotherapy treatments. 

Serious and Willful - applies to an injury caused by an employer’s failure to follow the law; applies only to the California state system.

Short-Lever Manipulation – A method of chiropractic manipulation in which contact is made on a vertebral process to move a single vertebra.

Shy-Drager Syndrome – Similar to some aspects of Parkinson’s disease this involves poor control of sympathetic functions.

Skeleton – The rigid framework of bones that gives form to the body.  It protects and supports the soft organs and tissues. It provides attachments for muscles.

Slight - under California law describes the severity of a pain as causing some hindrance in performing an activity; of "minimal," "slight," "moderate," and "severe."

Slipped disc – This is the same as a disc herniation or rupture.  It is a common term.  The disc usually does not actually “slip,” however.  Instead a portion of the disc breaks off or bulges into the spinal canal.  The broken disc may cause pain by pinching a nerve root.

Social Security - a Federal safety-net system which provides disability payments in addition to retirement benefits.

Spasm – A condition in which a muscle or group of muscles involuntarily contract or tighten up.

Special Report - a report submitted to the insurance company by the doctor when requested by the insurance company or required by law; describes the current complaints, examination findings, treatment advice, etc., or answers specific questions; applies only to the California state system.

Spinal Adjustment – This is a chiropractic term that is used to describe method(s) to correct spinal problems, whether by hand or with an instrument. Some equate the terms "adjustment" and "manipulation."

Spinal Alignment – The healthy, normal spine has a number of gentle curves which are normal.  When the shape of the spine is not normal, it is said to be out of alignment.

Spinal Anesthetic – This is a numbing medicine or an anesthetic which is injected into the spinal canal fluid for surgery in the lower abdomen, pelvis, rectum, or other lower extremities.

Spinal Canal – The canal is bony channel formed by the vertebrae bones. The spinal cord and nerve roots lie within the canal and are protected by the bones.  The “spinal canal” is not the same as the “spine.”  The word “spine” describes only the bones and ligaments.

Spinal Column – This is the flexible column of bones extending from the base of the skull to the tailbone. It is made up of 33 vertebrae. The first 24 vertebrae are separated by discs, known as intervertebral discs, and bound together by ligaments and muscles. Five vertebrae are fused together to form the sacrum and 4 vertebrae are fused together to form the coccyx. The spine is also referred to as the vertebral column, the backbone, or simply the spine.

Spinal Cord – This is the main bundle of nerves that travels from the brain to the rest of the body.  It lies within the bony spinal canal.

Spinal Cord Monitoring – Used during surgery, this is a test to check the function of the spinal cord and make sure that there is no damage.

Spinal Disc – Intervertebral discs are soft tissue structures that are between the vertebral bones of the spine. They act as cushions but are easily damaged.

Spinal Fusion – A surgical procedure to permanently join vertebral bones, this is a major operation.  The surgeon permanently connects two or more bones to preventing movement.   This is the same as an arthrodesis. 

Spinal Instrumentation – The metal hardware used to secure the vertebral bones during a fusion operation is called instrumentation.

Spinal manipulation – A chiropractic and osteopathic technique.  This involves a forceful, high-velocity thrust that stretches a joint beyond its maximum range of movement in order to increase its mobility. Manipulation is usually accompanied by an audible pop or click. Because of the speed involved, the patient does not have control and the potential for injury is greater than exists with mobilization.

Spinal Stenosis – This is a reduction in the diameter of the spinal canal.  It may be congenital (a birth defect), the result of trauma or caused by arthritis.  It may result in pressure on the spinal cord or nerve roots.

Spine – The flexible column of bones extending from the base of the skull to the tailbone. It is made up of 33 vertebrae. The first 24 vertebrae are separated by discs, known as intervertebral discs, and bound together by ligaments and muscles. Five vertebrae are fused together to form the sacrum and 4 vertebrae are fused together to form the coccyx. The spine is also referred to as the vertebral column, the spinal column, or the backbone.

Spinous Process – This is the posterior bony strut that protrudes from the lamina of each vertebral bone.  It provides an attachment for the muscles.

Spondylitis – Inflammation of vertebral bones. Sometimes caused by infection and sometimes caused by medical diseases including certain types of arthritis.

Spondylolisthesis – A slippage of one vertebra over another.  This is a malalignment of the vertebral bones.  It is usually due to a break in the posterior portion of one of the vertebra.  It may be slight or severe.  It is generally graded from Grade 1 (the best) to Grade 5 (the worst).

Spondylolysis – A defect or crack in the posterior portion of one of the vertebral bones.  The broken part is called the pars interarticularis and is between the superior and inferior facet joints of the lamina.  It is usually due to a developmental defect but may be the result of a trauma.  It may cause instability or a slippage (a spondylolisthesis).

Spondylosis – Arthritis of the spine.  This may be due to degenerative disease or “wear and tear” of the vertebral bones.

Stage -- The measurement of the extent of a cancer or other disease.  This is one way to measure severity or spread.

Stainless Steel – An iron–based metal containing chromium, that is highly resistant to stain, rust, and corrosion. Stainless steel is commonly used to make surgical implants and instruments.

State Compensation Insurance Fund (SCIF) - a California state program which provides coverage for individuals disabled from work due to problems other than work injuries.

Stenosis – Latin for a narrowing.  A narrowing of the spine would be called a spinal stenosis.

Sterile – Free from living organisms. Something which is sterile contains no living bacteria, virus or fungus.

Sterilization – The method used to render a material free from living organisms. Usual methods include steam under pressure, poisonous gas, and ionizing radiation.

Stevens-Johnson syndrome (Johnson-Stevens Syndrome) – An allergic loss of much of the skin.  Often this is fatal if not treated early.

Straight Back Syndrome – A loss of the normal lumbar lordosis due to a poorly executed fusion, this results in difficulty walking.

Stinger – This term is commonly used by athletes and trainers to describe pain experienced with vigorous sports activity. A stinger describes a burning and sudden pain, most commonly in the low back, groin or neck area, it is often related to a muscle strain or an injured nerve root.

Straight Chiropractor – Chiropractors who believe the most traditional chiropractic's doctrines that most health problems are caused by misaligned spinal bones ("vertebral subluxations") and are correctable by manual manipulation of the spine.

Straight Leg Raise (SLR) –A technique for measuring sciatic nerve mobility and/or hamstring length.

Stress Fracture – A fracture caused by a non-traumatic, cumulative overload on a bone.  Many small insults or a number other factors, including overtraining, incorrect biomechanics, fatigue, hormonal imbalance, poor nutrition, and osteoporosis, can cause stress fractures.

Stressology – An intricate mathematical analysis used by some chiropractors and other alternative care providers to locate stress points in the spinal analysis.

Stroke Syndrome – The loss of neurologic function due to brain damage from a loss of the blood flow to an area of the brain.

Subacromial Joint -- A joint made up by the humoris, the acromion process of the clavicle, and the coracoid process of the scapula.  It is joined by the coracoacromial ligament and lined by the synovium of the subacromial bursa. It is part of the shoulder joint.

Subacromial Space – The region of the shoulder that is bordered by the subacromial joint.

Subchondral Tissue -- The smooth tissue at the ends of bones, which is covered with another type of tissue (called cartilage).

Subjectives - complaints or problems reported by the patient, one component of the disability rating; applies only to the California state system.

Substantia Nigra – A small area of the brain containing a cluster of black-pigmented nerve cells that produce dopamine which is then transmitted to the striatum.

Sublaminar Wires – Special metal wires that are used to attach hardware to the spinal lamina, and which go underneath and around the lamina, are called sublaminar wires.

Subluxation – The medical definition is an incomplete or partial dislocation or a condition, visible on x-ray films, in which the bony surfaces of a joint no longer face each other exactly but remain partially aligned. Chiropractors use the term many ways but in general "vertebral subluxations" mean treatable malpositioning of the spine bones.

Superficial – A structure that is above another, or further from the center of the body, is said to be more superficial.  This is the opposite of deep.

Superior – Situated above or directed upward toward the head of an individual. 

Supinate – To turn the palms up or the feet outward.  This is the opposite of pronate.

Surface electromyography (SEMG) – A that measures skin temperature and skin electrical activity.  Some chiropractors who use it claim that it provides evidence of nerve dysfunction associated with vertebral subluxations.

Surrogate testing – A method of diagnosing problems by testing the muscle strength of a person who is touching the patient. This is very controversial.  The doctor does not examine the patient.  Some chiropractors use this method to diagnose allergies, deficiencies, and other alleged problems in infants and small children.

Synapse – The tiny gap (or space) which forms the connection between the end of one nerve fibers and the beginning of another.  It is the areas across which nerve impulses pass travel one neuron to another.  At the synapse, an impulse causes the release of a neurotransmitter, which moves across the gap and triggers an electrical impulse in the next neuron.

Syncope – Light-headedness, or fainting, caused by insufficient blood supply to the brain.

Synovitis – The inflammation of the synovial membrane, the tissue that lines and protects the joint.

Synovium – The fibrous envelope that is inside most joints is like the oil filled spaces in a car motor.  It is composed of smooth, polished surfaces and it is filled with a lubricating fluid (synovial fluid) that acts like oil to help to reduce the friction and wear in a joint.

Sweat method – An atlas orthogonal technique used by chiropractors in which the atlas is adjusted using a special table and a solenoid stylus placed against the side of the neck just behind and below the ear.


If you are aware of any useful spine and neuromusculoskeletal terms which are not included in this list, or if you have suggestions for better definitions,  your help would be greatly appreciated.  Please send me any upgrades and I will update the web site appropriately.  Click here to send a comment.






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Last modified: 07/27/08