Tactile Fremitus

Tactile fremitus, also known as tactile vocal fremitus, refers to the vibration of the chest wall that results from sound vibrations created by speech or other vocal sounds. When a person speaks, airflow from the lungs causes the vocal cords in the larynx to vibrate. These vibrations, which are also known as vocal fremitus, are transmitted down the tracheobronchial tree and through the lung tissue to the chest wall, where they can be felt by the hand as a palpable vibration. 

Tactile fremitus is a clinical sign commonly assessed as part of a routine physical examination of the lungs. Respiratory physical examination generally consists of a visual assessment of the chest wall, palpation of chest expansion symmetry, tactile fremitus, percussion of the chest (which refers to the tapping of the thorax with the fingers), and lung auscultation (which uses a stethoscope to listen to an individual’s breathing sounds).

Changes in the intensity of tactile fremitus can be used to detect areas of unusual lung tissue density. The assessment of tactile fremitus is based on the principle that sound vibrations are conducted better through solid or fluid mediums, as opposed to air, which causes a decay in sound transmission. As a result, areas of increased lung tissue density are better conductors of sound, and generally present a more noticeable fremitus than normal air-filled lung tissue. Conversely, an excessive amount of air within the lungs may cause impaired sound transmission, leading to a decreased or absent tactile fremitus.

In combination with other clinical findings, tactile fremitus may be useful in suggesting an initial diagnosis that can then be confirmed by specific diagnostic tests. These tests may include blood tests, imaging techniques (chest x-ray, CT scan), or pulmonary function tests, depending on the potential clinical concern.

Decreased intensity of tactile fremitus may occur as a result of excessive amounts of air in the lungs (also known as hyperinflation). Hyperinflation can be seen in individuals with pulmonary emphysema, chronic obstructive pulmonary disease (COPD), asthma, or severe airway obstruction. 

Additionally, decreased or absent tactile fremitus may also occur when there is an increased distance between the lungs and the chest wall. For instance, excess fluid or air can collect in the pleural space; the thin fluid-filled cavity that forms between the two layers of serous membrane between the lungs and the chest wall. The buildup of excess fluid in the pleural space is known as a pleural effusion, whereas accumulation of air in the pleural space is known as a pneumothorax.