Topographic percussion of the lungs

Objectives and execution technique

The primary goals of topographic percussion are to determine the position of the lung apices and their lower borders, as well as to establish the precise dimensions and localization of potential pathological foci within the thoracic cavity.

Key technical rules for execution:

• The use of quiet percussion is mandatory.
• The pleximeter finger must be positioned strictly parallel to the border being determined (the line of percussion).
• The direction of movement during the examination follows sequentially along the ribs and intercostal spaces.

For the correct execution of the technique, it is important to know the anatomical landmarks. Anteriorly, ribs are always counted starting from the second rib, as the first is inaccessible for palpation (hidden by the clavicle). The primary anterior landmark is Louis' angle (the sternal angle)—the junction of the manubrium and the body of the sternum, where the 2nd rib attaches. Posteriorly, landmarks include the spinous process of the seventh cervical vertebra (C7, the most prominent point when the head is tilted forward) and the inferior angle of the scapula, which corresponds to the level of the 7th rib.

Determination of the lower borders of the lungs

Normally, the lower margins of both lungs lie at approximately the same level. However, there is an important anatomical exception: on the left, borders are not determined along the anterior lines. This is due to the adjacency of the heart and the presence of Traube's space tympanic sound (stomach and spleen), which muffles and distorts the clear pulmonary resonance. Therefore, on the left, the examination begins directly at the anterior axillary line.

Normal topographic landmarks of the lower borders:

Mobility of the lower pulmonary margin

Assessment of the excursion (mobility) of the lower margin reflects the functional reserves of the lungs. Measurement is traditionally performed along the midaxillary line.

Procedure:

1. Locate the lower border during quiet breathing.
2. Perform percussion during maximum inspiration, noting the downward displacement of the border.
3. Perform percussion during maximum expiration, recording the upward displacement of the border.

Normally, the displacement upon inspiration and expiration is approximately 4 cm each, yielding a total excursion of about 8 cm. If the patient is unable to hold their breath for any reason, percussion is performed during a series of regular deep breaths, allowing the physician to form a general impression of the range of motion of the lung margin.

Pathological displacement of borders

Alteration in the position of the lung borders can occur both cranially (upward) and caudally (downward).

Upward displacement of the border is most commonly caused by:

• Pleural pathology: fluid accumulation (hydrothorax) or gas (pneumothorax).
• High standing of the diaphragm due to abdominal causes (marked flatulence, ascites, obesity, pregnancy).

Such displacement leads to a decrease in the volume of functioning lung tissue and a reduction in vital capacity (VC), which threatens the development of respiratory failure and hemodynamic disorders in the pulmonary circulation.

Downward displacement of the border may be:

• Chronic: characteristic of pulmonary emphysema (accompanied by increased tissue airness). This displacement is permanent and tends to progress. The combination of border depression and decreased excursion is a critical diagnostic marker of emphysema.
• Acute: observed during a bronchial asthma attack due to expiratory difficulty, increased residual air volume, and acute lung hyperinflation.

Topographic anatomy and projection onto the chest wall

Knowledge of the projection of the lungs (pulmones) and their structures onto the chest wall is critical for visualizing pathologies.

The lung apices (apex pulmonis) project 2–4 cm above the clavicle anteriorly. The right lung consists of three lobes (superior, middle, and inferior), whereas the left lung has only two (superior and inferior).

Interlobar fissures (fissurae interlobares):

• Oblique fissure (fissura obliqua): present on both sides. It begins posteriorly at the spinous process of Th3, runs obliquely downward along the lateral surface, and ends anteriorly at the 6th rib along the midclavicular line. This fissure separates the inferior lobe (the main mass of which is projected posteriorly) from the upper divisions.
• Horizontal fissure (fissura horizontalis): present only in the right lung, separating the superior lobe from the middle lobe. Anteriorly, its course corresponds to the level of the 4th rib, and at the midaxillary line at the level of the 5th rib, it merges with the oblique fissure.

Also notable is the costodiaphragmatic recess (recessus costodiaphragmaticus)—the lowest part of the pleural cavity, into which the lung margin descends only during a deep inspiration. Anteriorly on the left, the cardiac notch is located, where the pericardium directly adjoins the chest wall without being covered by pleura.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Anatomical boundaries and clinical significance of Traube's space
• Detailed algorithm for palpating spinous processes of the vertebrae for counting ribs posteriorly
• Topography of pleural recesses (including the costodiaphragmatic recess) and their role in the diagnosis of hydrothorax
• Pathophysiology of pulmonary circulation disorders during displacement of lung borders

Other topics in the "Respiratory System" section

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