ROUB key terms

A fluid-filled space behind the fetal neck measured by ultrasound between roughly 11 and 14 weeks of pregnancy; increased thickness raises the chance of chromosomal and structural abnormalities.

The longest measurable length of the embryo or fetus from head to rump, used to date early pregnancy and to confirm the correct gestational window for nuchal translucency measurement.

A risk calculation for chromosomal conditions combining maternal age, nuchal translucency, and maternal blood markers, usually performed between 11 and 14 weeks of pregnancy.

A maternal blood test that analyzes placental DNA fragments to estimate the chance of common chromosomal conditions; it is a screening test, not a diagnostic confirmation.

An abnormal number of chromosomes in a cell, such as an extra copy of chromosome 21; it is the target of most prenatal genetic screening and requires diagnostic testing for confirmation.

A diagnostic procedure in which a needle guided by ultrasound withdraws amniotic fluid for genetic or biochemical testing, typically performed after 15 weeks of pregnancy.

A diagnostic procedure that samples placental tissue, usually between 10 and 13 weeks, to test fetal chromosomes or genes earlier than amniocentesis allows.

A fetal wellbeing assessment combining ultrasound observation of fetal breathing, movement, tone, and amniotic fluid volume with a nonstress test score.

A semi-quantitative ultrasound estimate of amniotic fluid obtained by summing the deepest vertical pocket in each of four uterine quadrants.

Abnormally low amniotic fluid volume for gestational age, which can reflect membrane rupture, placental insufficiency, or fetal urinary tract problems.

Abnormally increased amniotic fluid volume, associated with maternal diabetes, fetal swallowing problems, and gastrointestinal or neurologic abnormalities.

A placenta that covers or lies very close to the internal cervical opening, which can cause painless third-trimester bleeding and usually requires cesarean delivery.

Assigning fetal age from the last menstrual period or, more accurately, from early ultrasound measurements such as crown-rump length, which guide later screening and growth assessment.

A calculated fetal weight derived from ultrasound measurements of head, abdomen, and femur length, used to detect growth restriction or macrosomia.

A fetus that fails to reach expected growth potential, often identified by estimated fetal weight below the tenth percentile with abnormal Doppler findings.

A waveform study of umbilical artery blood flow used in growth-restricted pregnancies; increased resistance signals placental insufficiency and rising fetal risk.

An imaging approach using a probe placed in the vagina to give high-resolution views of the uterus, ovaries, and early pregnancy structures.

The measured distance of the closed cervix, usually by transvaginal ultrasound; a short value predicts increased risk of spontaneous preterm birth.

An embryo implanted outside the uterine cavity, most often in a fallopian tube; it is a life-threatening emergency that ultrasound helps identify early.

A fluid collection inside the uterus that can mimic an early gestational sac in ectopic pregnancy, distinguished by its central location and absent yolk sac or embryo.

The first visible ultrasound sign of intrauterine pregnancy, a fluid-filled structure within the endometrium that later contains a yolk sac and embryo.

Persistent tendon pain with structural change, often from overuse; imaging shows tendon thickening, hypoechoic areas, and sometimes increased blood flow.

A partial or complete disruption of tendon fibers, seen on ultrasound as a gap, retraction, or focal defect, often after acute trauma or chronic degeneration.

The group of four shoulder muscles and their tendons that stabilize the humeral head; supraspinatus and other cuff tendons are common ultrasound targets for tears.

Inflammation of the bursa beneath the acromion, shown on ultrasound as fluid distending the bursa, often with painful shoulder abduction.

Real-time imaging during active or passive movement, used to detect tendon subluxation, impingement, or instability that static images may miss.

An ultrasound mode sensitive to slow blood flow, useful in musculoskeletal imaging to show hyperemia in inflamed tendons, bursae, or joints.

Abnormal fluid within a joint space, appearing as an anechoic collection on ultrasound and often indicating inflammation, infection, or trauma.

A joint infection that causes effusion, pain, and restricted motion; ultrasound can detect the effusion and guide fluid sampling for diagnosis.

Using real-time ultrasound to place a needle into a joint, bursa, or cyst to remove fluid for diagnosis or to relieve pressure.

A layer of connective tissue separating muscles or compartments; ultrasound can identify these planes for regional nerve blocks and fluid tracking.

A false darkening of a tendon or nerve when the ultrasound beam strikes it at an oblique angle; the artifact disappears when the probe is angled perpendicular.

A rapid bedside ultrasound examination of the abdomen, pelvis, and chest to detect free fluid or blood after trauma.

The potential space between the liver and right kidney, a dependent area where free fluid collects and a key FAST window.

Fluid in the sac around the heart, seen as an anechoic stripe on echocardiography; a large or rapidly accumulating effusion can cause cardiac tamponade.

Compression of the heart by pericardial fluid that impairs filling, producing hypotension and shock; ultrasound shows a large effusion and chamber collapse.

The shimmering motion of the pleural line during breathing on lung ultrasound; its absence suggests pneumothorax.

Vertical, laser-like artifacts arising from the pleural line on lung ultrasound; multiple B-lines indicate interstitial fluid or pulmonary edema.

Air in the pleural space that separates lung from chest wall; ultrasound shows absent lung sliding and absent B-lines at the affected area.

Measuring the diameter and respiratory variation of the inferior vena cava to estimate right atrial pressure and intravascular volume status.

A limited bedside echocardiogram performed by non-cardiologists to answer specific questions such as presence of effusion, global function, or chamber size.

A blood clot in a deep vein, usually of the leg; compression ultrasound showing a noncompressible vein is the primary bedside diagnostic finding.

A technique in which the probe presses on a vein; a normal vein collapses, whereas a thrombosed vein stays noncompressible.

The percentage of left ventricular volume ejected with each heartbeat, a key measure of systolic function estimated visually or by measurement on echocardiography.

The percentage change in left ventricular internal diameter between diastole and systole, a simple M-mode measure of systolic function.

A one-dimensional ultrasound display showing motion of structures along a single line over time, used for cardiac timing and chamber measurements.

A graphic display of blood velocity over time; its shape and direction help assess flow, stenosis, and venous patency in vascular studies.

A Doppler-derived ratio describing waveform variability, calculated from peak, trough, and mean velocities; it rises with increased downstream resistance.

A clot obstructing pulmonary arteries, often arising from leg veins; bedside echocardiography may show right heart strain but cannot exclude the diagnosis.

Signs that the right ventricle is overloaded, such as dilation or reduced function on echocardiography, often seen with acute pulmonary embolism.

A fetal monitoring test that records heart rate patterns in response to fetal movement; reactive accelerations suggest adequate oxygenation and wellbeing.

Continuous or intermittent recording of fetal heart rate and uterine activity to detect patterns that suggest hypoxia or distress during labor.

Fetal blood vessels running across or near the internal cervical opening, which can rupture during labor and cause rapid fetal blood loss.

Delivery before 37 completed weeks of gestation, a leading cause of neonatal illness; short cervical length is a major predictive risk factor.

Fluid accumulation in the lungs that impairs gas exchange; lung ultrasound shows multiple B-lines and a wet appearance of the lung fields.