Kronig's spaces

Why Kronig's spaces are determined

Topographic percussion of the lungs includes mandatory examination of the upper boundaries. Doctors evaluate two main parameters: the height of the apices and Kronig's spaces (i.e., their width). This helps determine how aerated the tissue is in the uppermost parts of the respiratory system. The lung apex (apex pulmonis) is projected in the supraclavicular region and can be percussed both anteriorly and posteriorly. Measuring the width of the spaces complements the data on apex height, providing a more precise spatial picture of the lung tissue condition in this area.

Determination technique

The width of the lung apices is determined using quiet (subthreshold) percussion.

1. The doctor locates the middle of the patient's trapezius muscle.
2. The pleximeter finger is placed strictly perpendicular to the direction of the muscle fibers.
3. First, percussion is performed in a medial direction (toward the neck), delivering quiet strikes until the clear pulmonary resonance changes to dullness.
4. Then the finger is returned to the starting point in the middle of the trapezius muscle and percussed laterally (outward toward the shoulder), also waiting for a dull sound to appear.

The distance between the two identified points of sound dullness will constitute the width of Kronig's space.

Normal values of upper boundaries

Normally, the width of Kronig's spaces averages 5–6 cm, although individual constitutional variations from 3 to 8 cm are possible. For example, in a patient with a regular normosthenic chest shape, a space width of 7 cm on both sides is considered a variant of absolute norm.

For a comprehensive picture, the height of the apices is evaluated in parallel:

• Anteriorly: normally, the apices protrude above the clavicles by 3–4 cm. For measurement, the pleximeter finger is placed parallel to the clavicle and percussed from its midpoint upward and medially until dullness appears.
• Posteriorly: the apices are normally located at the level of the spinous process of the seventh cervical vertebra. Percussion is performed from the supraspinous fossa. The finger is placed parallel to the spine of the scapula and percussed from its midpoint upward to a point located 3–4 cm lateral to the spinous process.

Pathological changes

The dimensions of Kronig's spaces and the height of the apices can change in various diseases of the respiratory system. These shifts occur in both upward and downward directions.

• Widening of Kronig's spaces (along with upward displacement of the apices) is characteristic of pulmonary emphysema. In this disease, the lung tissue becomes excessively aerated, and the lung volume increases.
• Narrowing of Kronig's spaces (and downward displacement of the upper boundary) occurs with consolidation or shrinkage of the lung tissue. Such pathological changes are detected in pneumosclerosis, pulmonary fibrosis, or the presence of a local inflammatory infiltrate in the apex region.

Place in a comprehensive lung examination

Determining the width of the apices is always supplemented by examining the lower boundaries of the lungs and their mobility. Percussion of the lower edges is performed from top to bottom along vertical topographic lines. Anteriorly, the examination starts from the second to third intercostal space, laterally from the axillary fossa (patient's hands behind the head), and posteriorly from the seventh intercostal space (anchored by the angle of the scapula, corresponding to the VII rib).

The doctor records the transition of clear resonance to dullness (forming the lung-liver border on the right) or to dull-tympanic resonance (on the left above Traube's space, where the spleen and gastric fundus are located). Combined, normal Kronig's spaces, symmetrical lower boundaries, clear pulmonary resonance over all fields, and good chest excursion (about 5 cm) indicate the absence of pathological processes such as atelectasis, pulmonary congestion, or fluid accumulation in the pleural cavity.

Class and exam questions

What else to study on this topic

• Determination of the lower boundaries of the right and left lung along topographic lines
• Assessment of mobility (excursion) of the lower lung edge
• Causes of bilateral and unilateral lowering of the lower lung boundaries
• Pathologies leading to upward displacement of the lower lung boundaries
• Assessment of vocal fremitus and comparative percussion technique

Other topics in the "Additional Topics" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.