Fremitus

Fremitus is a palpable vibration on the human body. In common medical usage, it usually refers to (tactile) vocal fremitus, although there are several other types.

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Bronchial fremitus

See rhonchal fremitus below.

Hepatic fremitus

Hepatic fremitus is a vibration felt over the patient's liver. It is thought to be caused by a severely inflamed and necrotic liver rubbing up against the peritoneum. The name 'Monash sign' has been suggested for this clinical sign, after the Monash Medical Centre in Melbourne, Australia (Nagappan et al, 2001).

Hydatid fremitus

Hydatid fremitus is a vibratory sensation felt on palpating a hydatid cyst.

Pectoral fremitus

See vocal fremitus below.

Pericardial fremitus

Pericardial fremitus is a vibration felt on the chest wall due to the friction of the surfaces of the pericardium over each other. See pericardial friction rub for the auditory analog of this sign.

Periodontal fremitus

Periodontal fremitus occurs in either of the alveolar bones when an individual sustains trauma from occlusion. It is a result of teeth exhibiting at least slight mobility rubbing against the adjacent walls of their sockets, the volume of which has been expanded ever so slightly by inflammatory responses, bone resorption or both. As a test to determine the severity of periodontal disease, a patient is told to close his or her mouth into maximum intercuspation and is asked to grind his or her teeth ever so slightly. Fingers placed in the labial vestibule against the alveolar bone can detect fremitus.^[1]

Pleural fremitus

Pleural fremitus is a palpable vibration of the wall of the thorax caused by friction between the parietal and visceral pleura of the lungs. See pleural friction rub for the auditory analog of this sign.

Rhonchal fremitus

Rhonchal fremitus, also known as bronchial fremitus, is a palpable vibration produced during breathing caused by partial airway obstruction. The obstruction can be due to mucus or other secretions in the airway, bronchial hyperreactivity, or tumors. See rhonchus (rhonchi) for the auditory analog of this sign.

Subjective fremitus

Subjective fremitus is a vibration felt by the patient on humming with the mouth closed.

Tactile fremitus

See vocal fremitus below.

Tussive fremitus

Tussive fremitus is a vibration felt on the chest when the patient coughs.

Vocal fremitus

Vocal Fremitus, also called pectoral fremitus, or tactile vocal fremitus, is a vibration felt on the patient's chest during low frequency vocalization. Commonly, the patient is asked to repeat the phrase 'boy oh boy' (or any other diphthong such as 'toy boat' and 'blue balloons') while the examiner attempts to detect vibrations on the chest wall. The phrase 'ninety-nine' is also commonly used. The German language equivalent neun und neunzig, is a diphthong, and is appropriate.

Vocal fremitus is normally more intense in the right second intercostal space, as well as in the interscapular region, as these areas are closest to the bronchial bifurcation. Vocal fremitus is pathologically increased over areas of consolidation and decreased or absent over areas of pleural effusion or pneumothorax (collapsed lung).

The reason for increased fremitus in a consolidated lung is the fact that the sound waves travel quicker through liquid (the consolidation) than air. Conversely, the reason for decreased fremitus in a pleural effusion (or any pathology separating the pleura), is that this increased space between the pleura acts as a barrier to the sound waves.

It has recently been suggested that the artifacts caused by eliciting vocal fremitus during breast ultrasonography can be used to differentiate between benign and malignant tumors (Sohn and Baudendistel, 1995).

References

• Nagappan R, Parkin G, Tsui A, Sievert W (2001). "Hepatic fremitus: 'Monash sign'". Intern Med J 31 (9): 567-8. PMID 11767877.

• Sohn C, Baudendistel A (1995). "Differential diagnosis of mammary tumors with vocal fremitus in sonography: preliminary report". Ultrasound Obstet Gynecol 6 (3): 205-7. PMID 8521071.

• (2005) in Venes D: Taber's Cyclopedic Medical Dictionary, 20th Edition, Philadelphia, PA: F. A. Davis Company.  ISBN 0-8036-1208-7

• (2003) in Dorland WAM: Dorland's Illustrated Medical Dictionary, 30th Edition, Philadelphia, PA: W.B. Saunders Company.  ISBN 0-7216-0146-4