Four diagnostic methods--inspection, touching, moving, and pressing are discussed as follows:
In modem physics, a weak visible light with a wave length of 3800-4200 angstrom (equal to the wave length of blue light) can be irradiated from the body's surface. The brightness of this light is related to the age, sex, physique, and physiological condition of the individual. This is a specific phenomenon showing the body's functional condition. This weak visible light irradiated from the body is similar to Shen described in traditional Chinese medicine, and it may be the scientific explanation for Shen.
If the hand and foot skin is dull, dry or haggard due to a reduction of luster and moisture, it is called "Shishen" (loss of Shen) in traditional Chinese medicine. This indicates the worsening of diseases, with a poor prognosis and difficult to cure.
If the hand and foot are dark, lusterless, and appear covered with a layer like dark frost, this indicates a reduction of immunity and a high susceptibility to viral influenza, high fever, nephritis, leukemia, tumor or rheumatic fever.
Moving method:
When the fingers are extended in a neutral position, the range of active movement of the metacarpophalangeal joints are flexion to 90 degrees and dorsi-flextion to 0 degree or within a small angle, and some degree of medial and lateral deviation. The range of active movement of the proximal interphalangeal joints is flexion to 120 degrees, and the movement of the distal interphalangeal joints is flexion to 60 degrees.
Particular to human beings is the very flexible movement of the carpometacarpal joint of the thumb. When the thumb assumes a neutral position with its ulnar border kept in contact with the radial border of the index finger, it may dorsi-flex as the palm is pressed fiat on a table; it can also flex to assume an opposing posture with the palm; and it can again adduct and abduct (Fig. 4-2).
