Kronig's Fields

KRONIG'S FIELDS (Kronig), percussion projection of the lung apices onto the surface of the shoulder (figs. 1 and 2). The inner and outer borders of the fields are determined using light percussion (according to Goldscheider or according to Gausmann) in the supraclavicular fossa, above the spine of the scapula, and above the trapezius muscle. Percussion begins at the center of the field and is conducted sequentially inward and outward, and in the normal state the inner border is revealed with complete clarity, while the outer border always remains somewhat indistinct (since the outer surface of the lung apices descends outward and downward, gradually moving away from the surface of the shoulder). The normal width of the field according to Kronig is 1 cm; Neumann (W. Neumann) considers this figure exaggerated; when percussing in the supraclavicular fossae, he finds the width of the field in adults to be 5 cm and even 4¹/₂-4 cm;

Figure 2. Kronig's Fields from behind.

in children under 14 years of age, K. p. may not exceed 3 cm with healthy apices. In pulmonary emphysema, K. p. reach a width of 6 cm or more. In the case of induration and scarring of the apices, K. p. narrow due to the lowering of the inner border; in fresh infiltrates, the 'veiling' of this border, the disappearance of its distinctness, is particularly characteristic. Even greater significance is attributed to differences in the size of both Kronig fields (figs. 1 and 2). A difference not exceeding 1 cm is considered physiologically permissible; the finding of a difference exceeding 1 cm is recognized as an undoubted sign of changes in the corresponding apex.