S - Glossary of Terms

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S - Glossary of Terms

sac	(sak) Soft walled bag or pouch; any bladder like organ.
saccadic eye movements	(sa-kad´ik) Very rapid eye movements that occur constantly and that change the focus on the retina from one point to another.
sacculated	(sak'u-lat''ed). Having form of q sac or sacs; characterised by a series of pouched expansions or saccules.
saccule	(sak´yool) A sac like cavity in the membranous labyrinth inside the vestibule of the inner ear that contains a vestibular organ for equilibrium.
saccharide	A carbohydrate.
sacral	(sa´kral) Pertaining to the sacrum.
sacral plexus	(plek´sus) A network of nerve fibers that arises from spinal nerves L4 through S3. Nerves arising from the sacral plexus merge with those from the lumbar plexus to form the lumbosacral plexus and supply the lower extremity.
sacralisation	(sa"kral-i-sa'shun) Overdevlopment of one or both of transverse processes of last lumbar segment, with encroachment on or fusion with first sacral segment.
saddle joint	A synovial joint in which the articular surfaces of both bones are concave in one plane and convex or saddle shaped, in the other plane, such as in the distal carpometacarpal joint of the thumb.
safe industry	An industry that has an associated annual fatality accident rate of no more than 1 per 10,000 workers.
safelight	An incandescent lamp with a color filter that provides sufficient illumination in the darkroom while ensuring that the film remains unexposed.
sagittal	(saj'i-tal) Of or pertaining to sagittal suture of cranium pertaining to any plane parallel with median sagittal plane
sagittal plane	(saj´i-tal) Any anterior-posterior plane parallel to the long axis of the body.
sal	(sal) Latin for salt.
saline	(salin) Consisting of or containing a salt or salts; salty; saline solution, especially a physiologic, or so-called normal, salt solution.
salpingo-	(sal-ping'go-) Prefix denoting some relation to an oviduct.
salpinx	(sal'pingks) Oviduct.
salivary gland	(sal´i-ver-e) An accessory digestive gland that secretes saliva into the oral cavity.
sarcoma	(sar-ko'mah) Malignant tumor derived from tissue developed from mesoderm (connective and lymphoid tissue, bone, cartilage, muscle, and part of urogenital organs) and characterised by a fleshy consistency.
saturation current	A filament current that has risen to its maximum value because all of the available electrons have been used.
scala tympani	(ska´la tim´pa-ne) The lower channel of the cochlea that is filled with perilymph.
scala vestibuli	(ve-stib´yuu-le) The upper channel of the cochlea that is filled with perilymph.
scalar	Scalar Referring to a quantity or a measurement that has only magnitude.
scanned projection radiography (SPR)	Generalized method of making a digital radiograph; used in computed tomography for precision localisation.
scatter	Pertaining to radiography, scatter refers to radiation that enters a patient and is deflected from its initial course but may still contact and expose the X-ray film. Scatter radiation contributes to the patient radiation dose and degrades the radiographic image. See also scatter radiation.
scatter radiation	A type of secondary radiation composed of photons of lower energy than the incident photons which created them and which travel in a different direction. Scattered radiation is a product of the Compton effect and to a lesser degree coherent scatter. See also scatter.
scheduled maintenance	Maintenance procedures performed on a routine basis.
scientific notation	Exponential form.
scintillation detector	An instrument used in the detector arrays of many computed tomographic scanners.
sclera	(skler´ua) The outer white layer of fibrous connective tissue that forms the protective covering of the eyeball.
scleral venous sinus	(ve´nus) A circular venous drainage for the aqueous humor from the anterior chamber; located at the junction of the sclera and the cornea; also called the canal of Schlemm.
sclero-	(skler'o-) Prefix meaning hard, indurated, fibrous: also denotes relation to sclera of eye.
sclerosis	(skle-ro'sis) Hardening, or induration, of tissue, especially of interstitial connective tissue.
scoliosis	(sko"Ii-o'sis) Abnormal lateral curvature of the spinal column.
screen	see intensifying screen.
screen-film	Film made with thin emulsions (single- or double-sided) that is sensitive to either the blue or green light of fluorescent screens. Film should be matched to screen emissions.
screening mammography	An imaging examination performed on the breasts of asymptomatic women using a two-view protocol to detect unsuspected cancer.
screen lag	The phosphorescence in an intensifying screen.
screen speed	A relative number used to identify the efficiency of conversion of X-rays into usable light. Second (s) The standard unit of time.
screen unsharpness	The image unsharpness due to the size of the fluorescent crystals comprising the screens, the thickness of the screens, and/or the closeness of contact between the film and the screens.
scrotum	(skro´tum) A pouch of skin that contains the testes and their accessory organs.
sebaceous gland	(se-ba´shus) An exocrine gland of the skin that secretes sebum.
sebum	(se´bum) An oily, waterproofing secretion of the sebaceous glands.
secondary coil	The coil in which the induced current in an electromagnet flows.
secondary electron	The ejected electron from the outer shell of an atom.
secondary memory	Data stored on tape drives, diskettes, and hard disk drives.
secondary protective barrier	Barriers designed to shield areas from secondary radiation.
secondary radiation	Any radiation in the beam that is generated as a result of interactions of the primary beam with matter. At diagnostic energies, it is primarily composed of scattered photons, Compton electrons, characteristic radiation, and photoelectrons.
Second-generation computed tomographic scanner	A unit that incorporates the natural extension of the single-detector to a multiple-detector assembly intercepting a fan-shaped rather than a pencil-shaped X-ray beam.
secreta	(se-kre-tah) Any product of secretion: the secretions.
secrete	(se-kret') To separate substances from blood and emit as a secretion.
secretion	(se-kre-shun) Process of secreting; also, material secreted.
section thickness	The thickness of tissue that will not be blurred by tomography. The section thickness decreases as tomographic angle increases.
sedative	(sed'ah-tiv) Medication that has a calming effect.
selectivity	The ratio of primary radiation to scattered radiation transmitted through grid.
self-induction	The magnetic field produced in a coil of wire that opposes the alternating current being conducted.
self-rectified circuit	The X-ray tube itself serves as a rectifier where only the positive portion of the AC cycle is used; therefore, it is a type of half-wave rectified circuit. Electrons are only able to flow from the filament (cathode) to the target (anode) and not the reverse. In this sense it behaves like a diode.
semen	(se´men) The thick, whitish secretion of the reproductive organs of the male, consisting of spermatozoa and additives from the prostate and seminal vesicles.
semi-	(sem'i-) Prefix meaning partly; half or approximately half; as semiflexion, semiprone, semicoma.
semicircular canals	(Tubule channels within the inner ear that contain receptors for equilibrium.
semiconductor	Material that can serve both as a conductor and as an insulator of electricity.
semilunar valve	(sem´´e-loo´nar) Crescent- or half-moon-shaped heart valves positioned at the entrances to the aorta and the pulmonary trunk
seminal vesicles	(sem´i-nal ves´i-k'lz) A pair of accessory male reproductive organs lying posterior and inferior to the urinary bladder that secrete additives to spermatozoa into the ejaculatory ducts.
seminiferous tubules	(sem´´i-nif´er-us too´byoolz) Numerous small ducts in the testes, where spermatozoa are produced.
semipermeable membrane	(sem´´e-per´me-a-b'l) A membrane with pores of a size that permits the passage of solvent and some solute molecules while restricting the passage of other solute molecules.
senescence	(se-nes´ens) The process of aging.
sensitivity	The ability of an image receptor to respond to X-rays.
sensitivity center	The physical imperfections in the lattice of the emulsion layer that occur during the film manufacturing process.
sensitivity profile	The slice thickness.
sensitising agent	An agent that enhances the effect of radiation.
sensitometer	An optical step wedge that is used to construct a characteristic curve.
sensitometry	The study of the response of an image receptor to X-rays.
sensory area	A region of the cerebral cortex that receives and interprets sensory nerve impulses.
sensory neuron	(noor´on) A nerve cell that conducts an impulse from a receptor organ to the central nervous system; also called an afferent neuron.
sepsis	(sep'sis) Poisoning caused by absorption of pathogenic bacteria and their products from a putrefactive process.
septal line	A generic term for fine linear opacities of varied distribution produced by the interstitium between pulmonary lobules when the interstitium is thickened by fluid, dust deposition, cellular material etc. See also Kerley’s lines.
septic	(sep'tik) Putrefactive; produced by or caused by pathogenic bacteria.
septum	(sep´tum) A membranous or fleshy wall dividing two cavities.
sequestering-agent	An agents introduced in the developer to form stable complexes with metallic ions and salts.
sequestrum	(se-kwes'trum) Piece of dead bone that has become detached as a result of trauma or necrosis.
serosa	Outer layer of a viscus (especially in the alimentary tract).
serous membrane	(ser´us) An epithelial and connective tissue membrane that lines body cavities and covers visceral organs within these cavities; also called serosa.
serum	(ser´um) Blood plasma with the clotting elements removed.
sesamoid bone	(ses´a-moid) A membranous bone formed in a tendon in response to joint stress (e.g., the patella).
shaded surface display (SSD)	A computer-aided technique that identifies a narrow range of values as belonging to the object to be imaged and displays that range.
shadow dose equivalent (HS)	The dose of radiation to which the external skin or an extremity is exposed.
shadowgram	(shad'o-gram) Radiograph: a roentgenogram.
shadowgraph	(shad'o-graf) Radiograph: a roentgenogram.
shadow shield	A shields that is suspended over the region of interest and that casts a shadow over the patient's reproductive organs.
shape distortion	A kind of distortion caused by elongation or foreshortening.
sharpness	see resolution.
shells	The orbital energy levels surrounding the nucleus of an atom.
shell-type transformer	A transformer that confines more of the magnet field lines of the primary winding because there are essentially two closed cores.
shock	As it relates to the cardiovascular system, this term refers to a rapid, uncontrolled fall in blood pressure, which in some cases becomes irreversible and leads to death.
short gray scale	A high-contrast radiograph that exhibits black to white in just a few apparent steps.
shoulder	The region of the body where the humerus articulates with the scapula.
SID	Acronym for source to image receptor distance. The distance from the x-ray tube to the image receptor.
sialaden	(si-al'ad-en) Salivary gland.
sialography	(si"al-og'ra-fe) Radiographic examination of a salivary gland or duct after injection of radiopaque contrast medium.
sievert (Sv)	Special name for the SI unit of dose equivalent and effective dose. 1 Sv = 1 Jkg-' = 100 rem.
sight development	A manual method of film processing where the development time is determined visually; it is therefore subjective and variable.
sigmoid colon	(sig´moid ko´lon) The S-shaped portion of the large intestine between the descending colon and the rectum.
sigmoid-type (S-type) dose-response relationship	Sigmoid-type (S-type) dose-response relationship
silhouette (cardiac)	Outer border of the heart, seen against the radiolucent lungs.
silhouette sign	The effacement of an anatomic soft tissue border by consolidation of the adjacent lung or accumulation of fluid in the contiguous pleural space. This is a sign of conformity, and, hence, of the probable adjacency of a pathologic opacity to a known structure. The silhouette sign is useful for detecting and localising consolidation along the axis of the x-ray beam.
silicosis	(sil''i-ko'sis) Condition of lungs caused by prolonged inhalation of dust particles of stone or silica; a type of pneumonoconiosis.
silver bromide	The material that makes up 98% of the silver halide crystals in a typical emulsion.
silver halide crystals	The active ingredient of the radiographic emulsion. It is instrumental in creating a latent image on the radiograph.
silver iodide	The material that makes up 2% of the silver halide crystals in a typical emulsion.
Sim's position	(simz) Position in which body is semiprone, lying on left side, with right knee drawn up.
similar triangles	Two triangles in which corresponding angles are equal. A useful principle for calculating magnification factor.
sinciput	(sin'si-put) Forehead; anterior part of cranium.
sine	(si'ne) Latin for without; symbols.
sine wave	The variation of movement of photons in electrical and magnetic fields
single-target hit model	A model of radiation dose-response relationships for enzymes, viruses, and bacteria.
sinistrad	(sin'is-trad) Directed toward left; opposite of dextrad.
sinistro-	(sin'is-tro-) Prefix meaning left, as in sinistrocardia, sinistrocerebral.
sinoatrial node	(sin´´no-a´tre-al) A mass of specialized cardiac tissue in the wall of the right atrium that initiates the cardiac cycle; the SA node; also called the pacemaker.
sinus	(si´nus) A cavity or hollow space within a body organ, such as a bone.
sinusoid	(si´nu-soid) A small, blood-filled space in certain organs, such as the spleen or liver.
sinusoidal	Simple motion; a sine wave.
skeletal muscle	A specialized type of multinucleated muscle tissue that occurs in bundles, has crossbands of proteins, and contracts in either a voluntary or involuntary fashion.
skiagraph	(ski'ah-graf) Old term for radiograph or roentgenogram.
skiagram	(ski'ah-gram) Old term for radiograph or roentgenogram.
Skin erythema dose (SED)	A dose of radiation, usually about 200 rad or 2 Gy, that causes a redness of the skin.
slice thickness	The thickness of the tissue being imaged.
slice-acquisition rate (SAR)	A measure of the efficiency of a multislice spiral computed tomographic scanner.
slip ring technology	Technology that allows the gantry to rotate continuously without interruption, making spiral computed tomography possible.
sludge	Deposits on the film resulting from dirty or warped rollers, causing emulsion pick-off and gelatin buildup.
small intestine	The portion of the GI tract between the stomach and the cecum whose function is the absorption of food nutrients.
smooth muscle	A specialized type of nonstriated muscle tissue composed of fusiform, single-nucleated fibers. It contracts in an involuntary, rhythmic fashion within the walls of visceral organs.
sodium carbonate	An alkali compound contained in the developer.
sodium hydroxide	An alkali compound contained in the developer.
sodium sulfite	The preservative added to the developer that keeps it clear.
soft copy	The output on a display screen.
soft palate	(pal´at) The fleshy, posterior portion of the roof of the mouth, from the palatine bones to the uvula.
soft tissue radiograph	Radiography in which only muscle and fat structures are imaged.
software	The computer programs that tell the hardware what to do and how to store data.
soft x-ray	An X-ray that has low penetrability and therefore is of low quality.
solenoid	Helical winding of current-carrying wire that produces a magnetic field along the axis of the helix.
solid-state diode	A diode that passes electric current in only one direction.
solution	(so-lu'shun) A suspension of particles or molecules in a fluid.
solvent	A liquid into which various solids and powders can be dissolved.
somatic	(so-mat´ik) Pertaining to the nonvisceral parts of the body.
somatic cells	All the cells of the body except the oogonium and spermatogonium.
somatic effects	Effects of radiation, such as cancer and leukemia, limited to an exposed individual. See also genetic effect.
sounds of Korotkoff	(ko-rot´kof) The sounds heard when pressure measurements are taken. These sounds are produced by the turbulent flow of blood through an artery that has been partially constricted by a pressure cuff.
source-to-image receptor distance (SID)	The distance from the x-ray tube to the image receptor.
Source-to-skin distance (SSD)	The distance from the patient's skin to the fluoroscopic tube.
space charge	The electron cloud near the filament.
space-charge effect	The phenomenon of the space charge that makes it difficult for subsequent electrons to be emitted by the filament because of the electrostatic repulsion.
spasm	(spaz'm) Involuntary, convulsive contraction of a muscle or muscles.
spatial distortion	The misrepresentation in the image of the actual spatial relationships among objects.
spatial frequency	The measure of resolution; usually expressed in line pairs per millimeter (lp/mm).
spatial resolution	The ability to image small objects that have high subject contrast.
spatial uniformity	The constancy of pixel values in all regions of the reconstructed image.
special quantities	Additional quantities designed to support measurement in specialised areas of science and technology.
specific gravity	(spe-sif'ik grav'i-te) Relative density or weight of any volume of a substance compared with that of an equal volume of water at same temperature and pressure.
spectrum	The population of photons, usually plotted as intensity versus energy, see X-ray spectra.
spectrum matching	Use of rare earth screens only in conjunction with film emulsions that have light absorption characteristics matched to the light emission of the screen.
speed	Term used to loosely describe the sensitivity of film to X-rays, see film speed.
speed index	The step that has an average optical density closest to, but not less than, 1.2.
sperm	See spermatozoa.
spermatic cord	(sper-mat´ik) The structure of the male reproductive system composed of the ductus deferens, spermatic vessels, nerves, cremaster muscle, and connective tissue. The spermatic cord extends from a testis to the inguinal ring.
spermatocyte	A mature spermatogonia.
spermatogonium	The male germ cell.
spermatozoa	A functionally mature male germ cell.
sphincter	(sfingk´ter) A circular muscle that functions to constrict a body opening or the lumen of a tubular structure, as sphincter ani, sphincter of Oddi, pyloric sphincter.
sphincter of ampulla	The muscular constriction at the opening of the common bile and pancreatic ducts; also called the sphincter of Oddi.
sphincter of Oddi	(o´de) See sphincter of ampulla.
sphygmomanometer	(sfig´´mo-ma-nom´i-ter) A manometer (pressure transducer) used to measure the blood pressure.
spicule	(spik'ul) Minute, needlelike fragment, especially of bone.
spin density	A measure of the concentration of nuclei (number of the nuclei per given volume) contributing to the MR signal by release of energy following resonance. One of the major determinants of MR signal strength.
spina bifida	(spi'nah bifi-dah) Congenital malformation of vertebral arch in which there is a cleft in a lamina, with or without hernial protrusion of spinal cord and meninges.
spina bifida occulta	(spi'nah bifi-dah) Cleft in vertebral arch without herniation of spinal cord and meninges.
spinal cord	(spi´nal) The portion of the central nervous system that extends downward from the brain stem through the vertebral canal.
spinal ganglion	A cluster of nerve cell bodies on the posterior root of a spinal nerve.
spinal nerve	(One of the 31 pairs of nerves that arise from the spinal cord.
spindle fibers	The fibers that connect a centromere and two chromatids to the poles of the nucleus during mitosis.
spindles	The poles of the nucleus.
spinning top	A device used to check exposure timers.
spinous process	(spi´nus) A sharp projection of bone or a ridge of bone, such as on the scapula.
spiral / helical	The term given to computed tomography because it is the apparent motion of the x-ray tube during the scan.
spiral organ	The functional unit of hearing, consisting of a basilar membrane supporting receptor hair cells and a tectorial membrane within the endolymph of the cochlear duct; also known as the organ of Corti.
spiral pitch ratio	The relationship between the patient couch movement and x-ray beam collimation.
spirochete	Spiral type of bacterium of the genus Spirochaeta
spleen	(spl-en) A large, blood-filled, glandular organ located in the upper left quadrant of the abdomen and attached by mesenteries to the stomach.
spondylitis	(spon"di-li-tis) Inflammation of a vertebra or vertebrae.
spondylolisthesis	(spon"di-lo-lis-the'sis) Forward displacement of a lumbar vertebra. most frequently of last lumbar segment on sacrum.
spongy bone	(Bone tissue with a lattice like structure; also called cancellous bone.
spot film	Static image in small-format image receptor taken during fluoroscopy.
squamous	(skwa´mus) Flat or scalelike.
square law	The principle stating that one can compensate for a change in the source-to-object distance by changing the mAs by the factor SID squared.
staging	Determination of the amount of spread of a neoplasm, necessary to select appropriate therapy and to predict the future course of a disease.
stapes	(sta´p-ez) The innermost of the auditory ossicles that fits against the oval window of the inner ear; also called the stirrup.
starch	A plant polysaccharide.
stasis	(sta'sis) Defective circulation of blood: a slacking or stoppage of normal flow of contents of vessels or of any organ of body.
stationary anode	An X-ray tube design in which the anode is a single immobile structure. In medicine, this type is now limited almost entirely to dentistry. See rotating anode tube.
stator	Stationary coil windings located in the protective housing but outside the x-ray tube glass envelope. It is part of the electromagnetic induction motor.
stellate	(stel'at) Shaped or radiated like a star; as a stellate fracture of cranium.
stem cell	An immature or a precursor cell.
stenosis	(ste-no'sis) Stricture, or narrowing of lumen or orifice of a passage.
step-down transformer	A transformer in which the voltage is decreased from the primary side to the secondary side.
stepping	A computer-controlled capability on a patient table that allows imaging from the abdomen to the feet after a single injection of contrast media.
step-up transformer	A transformer in which the voltage is increased from the primary side to the secondary side.
step wedge	A filter used when radiographing a body part, such as the foot, that varies in thickness from one end to the other.
stereoradiography	The practice of making two radiographs of the same object and viewing through a device which allows each eye to view a different radiograph.
sternal angle	(sternal anal) Angle formed by junction of manubrium and gladiolus or body, of sternum.
sthenic	(sthen'ik) Referring to a body habitus of a patient who is strong and active; the average body habitus. Opposed to asthenia.
sthenic habitus	(sthen'ik) Bodily type characterised by strong build; a modification of more massive hypersthenic type.
stochastic effects	The probability or frequency of the biologic response to radiation as a function of radiation dose. Disease incidence increases proportionally with dose, and there is no dose threshold.
stoma	(sto'mah). Minute. mouthlike aperture; surgically established opening into intestine through abdominal wall; opening established between two anastomosed portions of intestine.
stomach	A pouchlike digestive organ located between the esophagus and the duodenum.
storage memory	The main computer memory where the program and data files are stored.
straight-line portion	The portion of a sensitometric curve where the diagnostic or most useful range of density is produced.
strangulated	(strang'gu-lat"ed). Compressed or constricted to arrest or congest circulation in a part; as a strangulated hernia, one in which protruding viscus is so constricted as to stop circulation.
stratified	(strat´i-f-id) Arranged in layers, or strata.
stratum basale	(stra´tum ba-sa´le) The deepest epidermal layer, where mitotic activity occurs.
stratum corneum	(kor´ne-um) The outer, cornified layer of the epidermis of the skin.
stria	(stri'ah) A strip or line; a streak, distinguished by colour, elevation or texture.
stricture	(strik'tur) Circumscribed narrowing of a canal; a constriction.
strip density	In a radiographic grid, the number of lead strips per inch of grid.
stroma	(stro´ma) A connective tissue framework in an organ, gland, or other tissue.
stromal	Referring to part of an organ that is composed of connective tissue and vasculature that provides structure to the organ.
structured mottle	A type of radiographic mottle due to variations in the structure of the intensifying screen. A factor which is spatially fixed, reproducible, not statistically variable, and the same in every image produced with a particular cassette/grid combination. Grid lines visible in the image can be considered structured mottle.
sub-	(sub-) Prefix meaning below, under, beneath; as subnormal, sublillgual„subdiaphragmatic.
subacute	(sub'ah-kut) Between acute and chronic; having some acute symptoms.
subcutaneous	(sub"ku-ta'ne-us) Situated beneath skin.
subarachnoid space	(sub´´a-rak´noid) The space within the meninges between the arachnoid mater and pia mater, where cerebrospinal fluid flows.
subatomic particle	A particle smaller than the atom.
subchondral	Just beneath the articular margin.
subcostal plane	vertebral level L2/3. This is the plane marking the lowest point of the ribcage
subcutaneous	Beneath the skin
subdural space	a potential space (i.e. not normally present) between the closely adjacent arachnoid and dura mater. (see meninges, subarachnoid space)
subject contrast	The part of radiographic contrast determined by the size, shape, and X-ray attenuating characteristics of the subject being examined and the energy of the X-ray beam. See also image receptor contrast.
sublingual gland	(sub-ling´gwal) One of the three pairs of salivary glands. It is located below the tongue and its duct opens to the side of the lingual frenulum.
subluxation	Incomplete or partial dislocation.
submandibular gland	(sub´´man-dib´yuu-lar) One of the three pairs of salivary glands. It is located below the mandible and its duct opens to the side of the lingual frenulum.
submentovertex	(sub"men-to-ver'teks) Directed from below chin to vertex; pertaining to region beneath chin and vertex; submentovertical.
submucosa	(sub´´myoo-ko´sa) A layer of supportive connective tissue that underlies a mucous membrane.
submucosal plexus	(sub´´myoo-k=os´al plek´sus) A network of sympathetic and parasympathetic nerve fibers located in the submucosa tunic of the small intestine; also called the plexus of Meissner.
substance	Any drug, chemical, or biologic entity.
subtraction technique	A method of removing all unnecessary anatomic structures from an image and enhancing only those of interest.
sulcus	(sul´kus) A shallow impression or groove.
supercomputer	One of the fastest and highest-capacity computers, containing hundreds to thousands of microprocessors.
superconductivity	The property of some materials to exhibit no resistance below a critical temperature.
superficial	(soo´´per-fish´al) Toward or near the surface.
superficial fascia	(fash´e-a) A binding layer of connective tissue between the dermis of the skin and the underlying muscle.
superior	(Toward the upper part of a structure or toward the head; also called cephalic.
superior vena cava	A large systemic vein that collects blood from regions of the body superior to the heart and returns it to the right atrium.
subphrenic	(sub-fren'ik) Situated or occurring below diaphragm.
sulcus	(sul'kus) A furrow: a groove; a fissure; especially one of sulci on surface of brain.
super-	(su'per-) Prefix meaning over, above, in excess; as superimpose, supernumerary, supersaturate.
supero-	(su'per-o) Prefix meaning above; situated or directed from above.
superoinferior	(su"per-o-in-fer'i-er) Directed from above downward; craniocaudal.
supination	(soo´´pi-na´shun) Rotation of the arm so that the palm is directed forward or anteriorly; the opposite of pronation.
supine	(su-pin') Lying on back; opposite of prone.
supporting tissue	Tissue that binds tissues and organs together.
supra-	(su'prah-) Prefix meaning above, higher in position; as supraclavicular, suprarenal, supraorbital.
suppuration	(sup"u-ra'shun) Process of generating and discharging pus.
surface anatomy	The division of anatomy concerned with the structures that can be identified from the outside of the body.
suspensory ligament	(suu-spen´suo-re) Two meanings - 1.A portion of the peritoneum that extends laterally from the surface of the ovary to the wall of the pelvic cavity. 2. A ligament that supports an organ or body part, such as that supporting the lens of the eye.
sustentaculum tali	(latin = support of the talus) a process on the medial aspect of the calcaneum, palpable inferior to the head of the talus.
sutural bone	(soo´chur-al) A small bone positioned within a suture of certain cranial bones; also called a wormian bone.
suture	(soo´chur) A type of fibrous joint found between bones of the skull.
sweat gland	A skin gland that secretes a fluid substance for evaporative cooling.
sympathetic	(sim´´pa-thet´ik) Pertaining to the division of the autonomic nervous system concerned with activities that, in general, arouse the body for physical activity, it is active when we are alert, fearful or stressed, dilating the pupils (see mydriasis) and speeding the heart. It is also important in temparature regulation (goosebumps, blushing/blanching and sweating); also called the thoracolumbar division. (see parasympathetic)
symphysis	(sim´fi-sis) A type of cartilaginous joint characterized by a fibrocartilaginous pad between the articulating bones, which provides slight movement; as symphysis pubis, ,symphysis menti.
symphysis pubis	(pyoo´bis) A slightly movable joint located anteriorly between the two pubic bones of the pelvic girdle.
synapse	(sin´aps) A minute space between the axon terminal of a presynaptic neuron and a dendrite of a postsynaptic neuron.
synarthrosis	(sin´´ar-thro´sis) Immovable joint (such as a cranial suture) in which only fibrous connective tissue intervenes between bones.
synchondrosis	(sin´´kon-dro´sis) A cartilaginous joint in which the articulating bones are separated by hyaline cartilage.
syncope	(sing'ko-pe) Temporary suspension of respiration and circulation with loss of consciousness; fainting.
syndesmosis	(sin´´des-mo´sis) A type of fibrous joint in which two bones are united by an interosseous ligament.
synergist	(sin´er-jist) A muscle that assists the action of the prime mover.
synovial cavity	(si-no´ve-al) A space between the two bones of a synovial joint, filled with synovial fluid.
synovial joint	A freely movable joint in which there is a synovial cavity between the articulating bones; also called a diarthrotic joint.
synovial membrane	The inner membrane of a synovial capsule that secretes synovial fluid into the joint cavity.
synovium	Specialised connective tissue that secretes synovial fluid to lubricate the articular surfaces.
system	A group of body organs that function together.
systemic	(sis-tem´ik) Relating to the entire organism rather than to individual parts.
systemic anatomy	The division of anatomy concerned with the structure and function of the various systems
systemic circulation	The portion of the circulatory system concerned with blood flow from the left ventricle of the heart to the entire body and back to the heart via the right atrium (in contrast to the pulmonary system, which involves the lungs).
systole	(sis´to-le) The muscular contraction of a heart chamber during the cardiac cycle.