Sacrum: The triangular shaped bone located just below the last Lumbar vertebra (L5). It is formed by five fused vertebra and creates the sacroilliac joints between the left and right portions of the pelvis called the iliums.
Sciatica: Pain along the course of the sciatic nerve, (the longest nerve in your body), usually caused by compression, inflammation, or reflex mechanisms. The sciatic nerve runs from your lower spine, through your buttocks, then into your leg and foot. There are actually two (2) sciatic nerves, one in each leg. When the sciatic nerve is inflamed, it can cause numbness, tingling, pain or weakness in your lower back, back of the thigh and lower leg.
Sclerotome/ Sclerotomal Pain: A sclerotome is an embryonic region which during fetal development differentiates into a variety of different body structures.
These parts may or may not be neurologically connected but are understood to have some physiological relationship. Many spinal structures such as the disk, cartilage, joint capsules and ligaments refer pain along sclerotomal distributions. Researchers have demonstrated these relationships repeatedly over the years and mapped out their referral distributions quite well. In fact, sclerotomal referral patterns have been published in many indexed medical journals beginning with the early work of Kellgren in 1939, Inman and Saunders 1944, Feinstein et al 1954, Bogduk in 1988. The below diagram illustrates scleratomal pain patterns on the left vs. dermatomal or radicular pain patterns on the right. Courtesy of the Spine Research Institute of San Diego.
Scoliosis: Scoliosis is an abnormal, curvature of the spine with a predilection for teenage girls. Usually seen at the time of puberty, it is a “C” or “S” shaped spinal configuration visualized from the back. In its milder form, it can often by reduced by manipulative treatments, braces or exercises. In its severe form, it can change the chest cavity shape, affecting heart and lung function and may require surgery to correct.
Scope of Practice: The legal definition of the activities that can be performed by a medical doctor, chiropractic physician, osteopathic physician, podiatrist, dentist, psychologist, counselor or therapist as regulated by each state board.
Sensory: The "feeling" portion of a nerve; as opposed to motor. Sends information from the body to the brain to be processed concerning touch, pressure, tickle, hot, cold, vibration, etc...
Somato-Visceral: Nerve pathways originating in the spinal cord and communicating with the internal organs.
sEMG: Surface electromyogram. A test that is used to record the electrical activity of muscles. When muscles are active, they produce an electrical current. This current is usually proportional to the level of the muscle activity. A sEMG is non-invasive and utilizes an instrument on the skin. Surface EMG can be used to detect abnormal muscle electrical activity that can occur in many diseases and conditions and is controversial as a diagnostic tool but provides good information concerning the documentation of continual muscle spasm activity.
Shear: Also known as shear strain; a deformation of a solid body, in which a plane in the body is displaced parallel to itself relative to parallel planes in the body; an example would be the C5 vertebra moving anteriorly while C6 vertebra remains stationary. Shear forces are often responsible for automobile trauma injuries and sports injuries to the ligament, cartilage and disk. Less frequently a shear force may result in the fracture of long bones such as the arms or legs.
SPECT: A form of imaging, a single-photon emission computerized tomography (SPECT) procedure lets your doctor analyze the function of your internal organs. A SPECT scan is a type of nuclear imaging test, which means it uses a radioactive substance and a special camera to create pictures of your organs. While imaging tests such as X-rays can show what the structures inside your body look like, a SPECT scan produces three-dimensional images that show how your organs work — for instance, how blood flows to your heart or what areas of your brain are more active or less active.
Spinal nerves: Spinal nerves supply movement, sensation and function of muscles in the upper and lower extremities as well as information to organ systems. When these nerves are pinched or irritated, loss of function of the organ systems as well as pain can be caused, radiating down the upper or lower extremities.
Spinous Process: A posterior protruding part of the vertebra that can be seen or felt when examining the spine.
Spondylolisthesis: Simply means that one vertebra has slipped forward of another.It generally results from a "break" in the bone section that helps the vertebra to stay connected to each other 
(known as the pars interarticularis), but can also result from degenerative changes in the joints holding the bones together. This condition may cause low back pain and lower extremity (buttocks, leg and calf) pain when the slipped vertebra compresses the nerve(s). most common at L5, spondylolisthesis is graded from I. to IV.; according to the amount of slippage. Grade I. indicates up to a 25% slippage, Grade IV indicates over 75% slippage. http://www.spineuniverse.com/displayarticle.php/article114.html
Stenosis: This is the term used to reflect narrowing of the spinal canal, the neuroforamen, or between the joints of the spine. This narrowing may cause compression or "pinching" of the spinal cord or nerve roots exiting the spinal canal. This is usually due to the process of spinal degeneration that occurs with aging. It can be caused by spinal disc herniation, osteoporosis, or tumor. Spinal stenosis may affect the cervical spine, the lumbar spine or both. Lumbar spinal stenosis results in low back pain as well as pain or abnormal sensations in the legs, and can even lead to the loss of bladder or bowel control. http://www.niams.nih.gov/hi/topics/spinalstenosis/spinal_sten.htm#spine_h
Stop codon (or termination codon): is a nucleotide triplet within messenger RNA that signals a termination of translation. Proteins are unique sequences of amino acids, and most codons in messenger RNA correspond to the addition of an amino acid to a growing protein chain — stop codons signal the termination of this process, releasing the amino acid chain. In the standard genetic code, there are three stop codons: UAG ("amber"), UAA ("ochre"), and UGA ("opal" or "umber"); several variations to this most common set are known.
Sub failure: A condition of ligaments or joints in which the normal architecture is preserved grossly but in which internal disruption of fibers has weakened the tissue to the point that dynamic loads are no longer tolerated; ligamentous instability.
Subluxation: Dorland’s medical dictionary defines this as less than a dislocation. In chiropractic, there have been varying degrees of how this word is defined, our interpretation follows: when a part the spine looses its proper position, motion or function in regards to the normal biomechanics of movement. This may or may not result in pain, but will lead to dysfunction.
Subluxation Complex: A description used to describe the five parts of a subluxation:
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movement dysfunction nerve dysfunction muscle dysfunction cellular dysfunction tissue dysfunction and degeneration |
(restriction, abnormal structure) (irritation or compression) (spasms, trigger points) (inflammation) (arthritis, cartilage breakdown) |
Symptom: A warning signal sent from the tissues, organs and muscles to the brain that damage has occurred, and still may be occurring. Often symptoms are the last signs of disease/dysfunction, and the first things to resolve as healing occurs. Common symptoms are pain, tingling, and numbness. Symptoms do not have to be present to indicate problems. (e.g. Heart disease and cancer are present long before the symptoms)
Sympathetic nervous system: A part of the nervous system that serves to accelerate the heart rate, constrict blood vessels, and raise blood pressure.