S's Flashcards
scalloping
Refers to the shape of a border which appearsas a series of curved indentations. Used to describe lungmargins during pleural effusion or cranial edge of caudallydisplaced diaphragm during severe pulmonary overinflation(latter is also called tenting of the diaphragm).
scatter radiation
(1) X-rays that are deflected from their path by interactions with patient or other material between the source of x-rays and the detector, and (2) secondary,lower energy x-rays created by interactions with a material. Scatter radiation does not provide useful radiographic information, decreases image quality, and exposes patient and nearby personnel to unnecessary radiation. Scattered x-rays can be minimized using collimation, grid, or air gap.
scintigraphy
A radiologic procedure involving the use ofradioisotopes to provide functional information about anorgan or body part. Scintigraphy is very sensitive in the detection of disease but not very specific as to etiology.
serial radiographs
Images made in sequence either during a single study (e.g., gastrointestinal series, excretory urography) or over longer intervals of time (e.g., days or weeks) as follow-up evaluations to monitor progress and response to therapy of a disease or disorder.
sequestrum
A fragment of bone that has lost its blood supply and is no longer viable. A sequestrum may be located in a less opaque area of bone called an involucrum
sialography
A radiographic contrast study of the salivary ducts and glands.
skyline radiograph
Primary x-ray beam is tangential to area of interest. Frequently involves flexion or extension of a body part.
source-to–image detector distance (SID)
Distance between focal spot (source of x-rays) and the detector. In film radiography it is the focal-film distance.
signet ring sign
(1) End-on visualization of a bronchus and adjacent pulmonary artery or (2) a paragonimus lesion in which gas is present in a cyst along with a fluke. Appearregurgitation: Reflux of undigested food from esophagus into pharynx or nasal cavity.
sacrocaudal dysgenesis
Developmental anomaly consisting of absence of one or more sacral or caudal vertebrae.
sail sign
Refers to the normal thymus in an immature animal as seen on a ventrodorsal or dorsoventral radiograph; appears as a triangular-shaped soft tissue opacity structure in the cranial mediastinum, projecting toward the left. Sail sign is abnormal in adults.
sagittal
“Arrowlike”; associated with the long axis or ventrodorsal plane of the body, which extends from head to tail, dividing the body into right and left halves.
supinate
To rotate a limb outward so that the palmar or plantar surface faces upward or medial and the dorsal or cranial surface faces downward or lateral.
survey radiograph
A standard radiographic study of an area of the body (e.g., thorax, abdomen, head, extremity) made without the use of contrast medium.
syndactyly
Congenital anomaly in which two are more digits are fused.
synostosis
Fusion of normally separate bones. Other names: bony ankylosis.
synovial joint
A freely movable articulation with a joint cavity, joint capsule, synovial fluid, and articular cartilage. Other names: diarthrodial joint, diarthrosis.
synovial osteochondroma
benign nodular proliferation of synovial membrane (primary, uncommon) or damaged cartilage (secondary, common), which frequently results in free mineralized fragments in the joint.
systematic approach
An organized and deliberate method of examining a radiograph in order to avoid overlooking diagnostic information.
silhouette sign
See border effacement
source-to-object distance (SOD)
Distance between the focal spot (source of x-rays) and the object being radiographed (i.e., subject or patient). Other names: focal-object distance (FOD).
speed
A measure of the sensitivity of a film:screen system to x-rays and light.
spina bifida
Congenital anomaly in which failure of the lateral vertebral arches to fuse dorsally results in incomplete development of the dorsal spinal process(es).
spondylitis
Inflammation of a vertebral body, usually caused by infection (e.g., migrating foreign material).
spondylosis deformans
A noninflammatory degenerative disorder associated with the vertebral bodies and characterized by complete or incomplete bony bridging of ventral and lateral margins of vertebrae. NOT osteophytes.
static fog:
Radiographic artifact caused by static electricity; appears as blackened areas with irregularly branching patterns (resembles a picture of lightning) or as multiple foci (black dots) on a radiograph. Occurs more often in areas with low humidity (in some hospitals, antistatic strips are installed to discharge personnel prior to opening cassettes or handling film).
scoliosis
Lateral curvature of the spine
stenosing tenosynovitis involving the tendon of the abductor pollicis longus
A chronic inflammation caused by overuse and resulting in fibrosis, enthesophyte formation on the dorsomedial aspect of the distal radius, and restriction of tendon movement.
stress fracture
A break in bone caused by repetitive stress (micro-damage to bone occurs at a greater rate than can be offset by the reparative process).
stress radiography
Technique used to investigate joint instability or subluxation. The bones proximal and distal to a joint are stabilized and a medial-to-lateral, lateral-tomedial, or orthogonal force is applied to document abnormal widening of the joint space or displacement of bones.
string sign
(1) Appearance of barium in the narrowed lumen of the pylorus on a positive contrast study (e.g., gastrogram, upper GI study); a sign associated with pyloric stenosis. (2) Also used to describe the intestinal plication caused by adhesions or linear foreign material.
subluxation
Partial loss of contact between articular surfaces.
summation
Overlap of tissues in different planes which results in greater blockage of x-rays due to addition of attenuating characteristics of each tissue. Produces a whiter area on the radiograph at the site of overlap.
supinate
To rotate a limb outward so that the palmar or plantar surface faces upward or medial and the dorsal or cranial surface faces downward or lateral.
