Glossary of sonographic signs
Signs, artifacts, measurements, and core concepts — each cross-referenced to the modules where it appears. Search or filter to find a term.
26 terms
A-lines artifact
Horizontal reverberation artifacts parallel to and repeating below the pleural line. Indicate normal aeration or air (also seen in pneumothorax and COPD).
AAA threshold measurement
An infrarenal aortic diameter ≥ 3.0 cm (measured outer-wall to outer-wall) defines an abdominal aortic aneurysm.
Acoustic shadowing artifact
A dark band deep to a strongly reflecting/absorbing structure (e.g., a gallstone or bone). Clean shadowing helps confirm calculi.
Anisotropy artifact
The dominant MSK/nerve artifact: tendons and nerves appear falsely hypoechoic when the beam is not perpendicular to their fibers. Overcome by heel-toe angulation.
B-lines (lung rockets) artifact
Vertical, laser-like hyperechoic artifacts arising from the pleural line that erase A-lines and move with sliding. Three or more per field indicate interstitial syndrome (e.g., pulmonary edema).
See: Lung — Anterior (BLUE Protocol), RUSH — Rapid Ultrasound for Shock & Hypotension
Barcode / stratosphere sign sign
M-mode pattern of uniform horizontal lines with no granularity, indicating absent lung sliding — suggestive of pneumothorax.
See: Lung — Anterior (BLUE Protocol), eFAST — Right Upper Quadrant (Morison's Pouch)
Bat sign sign
Two adjacent rib shadows with the bright pleural line between them, resembling a bat. Confirms correct identification of the pleural line in lung ultrasound.
Cardiac tamponade concept
A pericardial effusion with diastolic collapse of the right ventricle or right atrium — a time-critical, obstructive cause of shock.
See: Cardiac — Subxiphoid (Subcostal) 4-Chamber, RUSH — Rapid Ultrasound for Shock & Hypotension
D-sign sign
Flattening of the interventricular septum on parasternal short axis, giving the LV a D-shape. Indicates right ventricular pressure or volume overload (e.g., massive PE).
See: RUSH — Rapid Ultrasound for Shock & Hypotension, Cardiac — Parasternal Long Axis (PLAX)
EPSS (E-point septal separation) measurement
The gap between the anterior mitral leaflet at peak opening and the interventricular septum. An increased EPSS correlates with reduced left-ventricular ejection fraction.
Exclamation-point sign sign
The main lobar fissure (a thin hyperechoic line) running from the gallbladder neck to the portal vein, confirming the gallbladder.
Lung point sign
The transition zone where sliding lung meets absent-sliding lung. Highly specific (near-pathognomonic) for pneumothorax and estimates its size.
See: Lung — Anterior (BLUE Protocol), eFAST — Right Upper Quadrant (Morison's Pouch)
Lung sliding sign
Shimmering movement of the visceral against the parietal pleura at the pleural line. Its presence rules out pneumothorax at that spot.
See: Lung — Anterior (BLUE Protocol), eFAST — Right Upper Quadrant (Morison's Pouch)
Mickey Mouse sign sign
At the portal triad, the portal vein (head) with the hepatic artery and common bile duct (ears). Also describes the common femoral vein/artery/great saphenous vein at the saphenofemoral junction.
See: RUQ / Biliary (Gallbladder), DVT — Common Femoral Vein (Compression)
Morison's pouch (hepatorenal recess) concept
The potential space between the liver and right kidney. The most sensitive site for free intraperitoneal fluid in a supine patient.
Optic nerve sheath diameter (ONSD) measurement
Measured 3 mm posterior to the globe; values greater than ~5–6 mm suggest raised intracranial pressure.
See: Ocular Ultrasound
Pericardial vs. pleural effusion concept
On PLAX, fluid anterior to the descending thoracic aorta is pericardial; fluid posterior to it is pleural.
See: Cardiac — Parasternal Long Axis (PLAX), Cardiac — Subxiphoid (Subcostal) 4-Chamber
Probe orientation convention concept
Radiology/abdominal: screen indicator on the left (marker to patient's right or head). Cardiology: indicator on the right — the same anatomy appears mirrored. State which you use.
See: Cardiac — Parasternal Long Axis (PLAX), Cardiac — Subxiphoid (Subcostal) 4-Chamber, Abdominal Aorta (AAA Screening), eFAST — Right Upper Quadrant (Morison's Pouch)
Quad sign sign
A pleural effusion bounded by the pleural line, two rib shadows, and the visceral 'lung line' — forming a quadrangular anechoic shape.
Retinal detachment sign
A hyperechoic membrane in the vitreous, tethered at the optic disc, that undulates with eye movement and does not cross the optic nerve.
See: Ocular Ultrasound
Seashore sign sign
M-mode pattern of motionless chest wall ('waves') over a granular 'sandy beach' from moving lung. Indicates lung sliding is present (normal).
See: Lung — Anterior (BLUE Protocol), eFAST — Right Upper Quadrant (Morison's Pouch)
Sinusoid sign sign
M-mode sinusoidal movement of the lung line toward and away from the pleural line with respiration, indicating a free-flowing pleural effusion.
Sonographic Murphy's sign sign
Maximal tenderness elicited when the centered gallbladder is compressed directly under the probe. The most sensitive sign of acute cholecystitis.
Spine sign sign
Visualization of the thoracic vertebral bodies above the diaphragm due to fluid (pleural effusion/hemothorax) transmitting sound, where normally aerated lung would obscure them.
See: eFAST — Right Upper Quadrant (Morison's Pouch), Lung — Anterior (BLUE Protocol)
Vein non-compressibility sign
Failure of a vein's walls to fully coapt under probe pressure — the key sign of deep vein thrombosis.
WES sign (wall-echo-shadow) sign
A gallbladder packed with stones: the wall, then the echogenic stone surface, then a clean posterior shadow.