(sownd )

[Middle English soun, ult. fr. L. sonus, sound]

1. Auditory sensations produced by vibrations; noise. It is measured in decibels (dB), which is the logarithm of the intensity of sound; thus 20 dB represents not twice 10 dB but 10 times as much. Repeated exposure to excessively loud noises, esp. in certain frequencies, will cause permanent injury to the hearing.
SEE: decibel; SEE: noise
2. A form of vibrational energy that gives rise to auditory sensations.
SEE: cochlea; SEE: ear; SEE: organ of Corti
3. Heart sounds.
SEE: diastole; SEE: systole

absent breath sounds

The lack of perceptible sounds of airflow during auscultation of the patient's chest.

ETIOLOGY
Absent breath sounds can be caused by a lack of breathing (apnea) or by lung disorders that block the transmission of the sounds to the surface of the chest, e.g., pneumothorax, pleural effusion.

adventitious breath sounds

Abnormal lung sounds heard when listening to the chest as the person breathes. These may be wheezes, crackles (rales), or stridor. They do not include sounds produced by muscular activity in the chest wall or friction of the stethoscope on the chest.

adventitious lung sounds

Crackles and wheezes superimposed on the normal breath sounds; indicative of respiratory disease. Most adventitious lung sounds can be divided into continuous (wheezing) and discontinuous (crackles) according to acoustical characteristics.

anasarcous sound

An obsolete term for a moist sound heard on auscultation when the skin is edematous.

audible sound

Sound containing frequency components between 15 and 15,000 Hz (cycles per second).

blowing sound

An organic murmur as of air from an aperture expelled with moderate force.

bottle sound

A noise such as fluid in a bottle.
SEE: amphoric

bowel sounds

Any of the normal sounds associated with movement of the intestinal contents through the alimentary tract. Auscultation of the abdomen for bowel sounds may provide valuable diagnostic information. Absent or diminished sounds are possible indications of paralytic ileus or peritonitis. High-pitched tinkling sounds are associated with intestinal obstruction.

breath sounds

Any of the respiratory sounds heard on auscultation of the chest. In a normal chest, they are classified as vesicular, tracheal, and bronchovesicular.

bronchial sounds

Any of the sounds not heard in the normal lung but occurring in pulmonary disease, indicating infiltration and solidification of the lung.
SEE: bronchial breathing

bronchovesicular sounds

A mixture of bronchial and vesicular sounds.

coarse breath sound

A vesicular lung sound that is lower pitched and louder than normal.

ETIOLOGY
Pneumonia, atelectasis, pulmonary edema, and other conditions may cause this type of breath sound.

cracked-pot sound

A tympanic resonance heard over air cavities. This percussion sound resembles that made by striking a cracked pot.

diminished breath sound

A soft, decreased, or distant vesicular lung sound as heard through a stethoscope.

ETIOLOGY
Diminished breath sounds are common in patients with poor respiratory effort, splinting, emphysema, and other lung conditions.

ejection sound

Any noise made during cardiac systole by the valves of the heart or the root of the aorta.

fetal heart sound

The sound made by the fetal heart.

friction sound

A leathery or rasping sound produced when two inflamed surfaces rub against each other.

heart sounds

The two sounds “lubb” and “dupp” heard when listening to the heart with a stethoscope. They arise from valve closure and muscular structures in the heart and are technically called S₁ and S₂. Third and fourth heart sounds may be present in some heart diseases.

physiological sound

A sound perceived when the auditory canals are closed. The sound is produced by the blood flowing through adjacent vessels.

respiratory sound

Any sound heard over the lungs, bronchi, or trachea.

split heart sound

An abnormal auscultatory finding during a cardiac examination, in which a heart sound that usually has a single component is heard as two distinct noises. It is suggestive of a deep inspiration (which draws more blood than normal into the chest) or a bundle branch block.

succussion sound

A splashing sound heard over a cavity with fluid in it.

to-and-fro sound

Rasping friction sounds of pericarditis.

tracheal sound

A sound normally heard over the trachea or larynx.

tubular sound

A sound heard over the trachea or large bronchi.

vesicular sound

A normal breath sound heard over the entire lung during breathing.

white sound

A sound made up of all audible frequencies.