In Medical Astrology, the signs indicate both general conditions of humor and temperament affecting the overall physiology and metabolism of the entire organism; they also have affinities with different parts of the body. The general indications of a sign derive from its polarity, element, modality and planetary dignities. The specific indications of a sign in terms of parts of the body derive from its position or sequence within the wheel of the zodiac, as well as its basic symbolism and archetypes.
The Two Zodiacs
Most Western forms of astrology use the tropical zodiac, which is based on the annual solar cycle of the seasons. Vedic and many eastern forms of astrology use the sidereal zodiac, which is based on the Moon and the celestial constellations of fixed stars. Although each system has its own advantages, it's quite fitting to use a solar, tropical frame of reference for Medical Astrology because it deals with the condition and expression of one's health, energy and vitality, which are solar functions and attributes.
Element and Temperament
A sign's dominant or primary temperament is determined by its element, as follows:
The primary temperament of the Fire signs - Aries, Leo and Sagittarius - is Choleric.
The primary temperament of the Earth signs - Taurus, Virgo and Capricorn - is Melancholic.
The primary temperament of the Air signs - Gemini, Libra and Aquarius - is Sanguine.
The primary temperament of the Water signs - Cancer, Scorpio and Pisces - is Phlegmatic.
Modality: Cardinal, Fixed and Mutable
A sign's modality isn't directly involved with its temperament, but is nevertheless important. In Medical Astrology, a sign's modality concerns the basic reactions or response patterns of the organism to pathogenic factors and the disease process.
The response patterns of the Cardinal signs are very simple and clear-cut. The onset of an illness is usually clear and definite, and so is its remission; often, sudden, dramatic onsets and remissions may alternate. The Cardinal signs are predisposed to acute disorders, and have a moderate level of inherent vitality and resistance to disease. The Cardinal signs are Aries, Cancer, Libra and Capricorn.
The Fixed signs are long on endurance and persistence, and generally have the highest inherent vitality and resistance to disease. But once disease gains a foothold, it similarly becomes persistent and tenacious, and often becomes chronic. The eliminative functions are also slow and sluggish in the Fixed signs, and detoxification poor; once toxins, pathogens and morbid humors gain a foothold, they're also difficult to expel. The Fixed signs are Taurus, Leo, Scorpio and Aquarius.
The Mutable signs are flexible and adaptable, and know how to roll with the punches. They're usually beset by a long succession of minor complaints that come and go. Inherent vitality and resistance to disease is usually lowest in the Mutable signs, which tend to have a sensitive, allergic nature. The Mutable signs rule the digestive and respiratory tracts, which are always in intimate contact with the outer environment, and therefore allergically and immunologically challenged. The Mutable signs are Gemini, Virgo, Sagittarius and Pisces.
The two basic parameters that define a sign are its particular combination of element and modality. A sign's element defines its basic nature or content, whereas its modality defines its basic energetics and dynamics.
Sign Element and Polarity
Two of the Four Elements, Fire and Air, are Hot and Yang, and are light, subtle and energetic. They're more extroverted, emissive, and deal with the vital, energetic systems of the body. The Yang, emissive signs are Aries, Gemini, Leo, Libra, Sagittarius and Aquarius.
Two of the Four Elements, Water and Earth, are Cold and Yin, and are heavy, gross and substantial. They are more introverted, receptive and reflective, and deal with the substance and nutrition of the organism, or the Natural Faculty. The Yin, receptive signs are Taurus, Cancer, Virgo, Scorpio, Capricorn, and Pisces.
Planetary Dignity and Subtemperament
In Greek Medical Astrology, the dominant or primary temperament of a sign is determined by its element, but its subtemperament is determined by its planetary dignities. These planetary dignities include a sign's classical domicile ruler, its modern ruler, if any, and its planetary exaltation, if any. The inherent temperaments of the planets are used to determine a sign's subtemperament.
When we put a sign's planetary dignities and subtemperament together with its element or primary temperament, we get the following:
Aries - Cardinal Fire: Choleric primary temperament. Choleric subtemperament - Mars ruler, Sun exaltation. Purely Choleric.
Taurus - Fixed Earth: Melancholic primary temperament. Sanguine / Phlegmatic subtemperament - Venus ruler, Moon exaltation.
Gemini - Mutable Air: Sanguine primary temperament. Nervous subtemperament - Mercury ruler.
Cancer - Cardinal Water: Phlegmatic primary temperament. Phlegmatic subtemperament - Moon ruler. Purely Phlegmatic.
Leo - Fixed Fire: Choleric primary temperament. Choleric subtemperament - Sun ruler. Purely Choleric.
Virgo - Mutable Earth: Melancholic primary temperament. Nervous subtemperament - Mercury ruler and exaltation. Purely Nervous / Melancholic.
Libra - Cardinal Air: Sanguine primary temperament. Sanguine subtemperament - Venus ruler. Purely Sanguine.
Scorpio - Fixed Water: Phlegmatic primary temperament. Choleric subtemperament - Mars domicile ruler, Pluto modern ruler.
Sagittarius - Mutable Fire: Choleric primary temperament. Sanguine subtemperament - Jupiter ruler.
Capricorn - Cardinal Earth: Melancholic primary temperament. Melancholic subtemperament - Saturn ruler.
Aquarius - Fixed Air: Sanguine primary temperament. Nervous / Melancholic subtemperament - Saturn domicile ruler, Uranus modern ruler.
Pisces - Mutable Water: Phlegmatic primary temperament. Sanguine subtemperament - Neptune modern ruler; Jupiter domicile ruler, Venus exaltation.
The Cardinal signs, in keeping with their simple, clear-cut nature, are all of pure, simple temperament. Of the Fixed signs, one, Leo, is of pure temperament: Choleric. Of the Mutable signs, one, Virgo, is purely Nervous / Melancholic.
The Wet Air and Water elements, which bond and unite, have only one sign each of pure temperament - their Cardinal sign, the others being mixed. The Dry Fire and Earth elements, which tend towards separation and discreteness, have two signs each of pure temperament.
The zodiac is evenly divided, with six signs of pure temperament and six signs of mixed temperament. The pure signs are Aries, Cancer, Leo, Virgo. Libra and Capricorn. The mixed signs are Taurus, Gemini, Scorpio, Sagittarius, Aquarius and Pisces.
Body Parts and the Cosmic Man
The wheel of the zodiac is a great cosmic mandala representing wholeness. It is likened to the body of a Great Cosmic Man. The individual signs comprising it correspond to the various parts of his body, starting with Aries at the head and ending with Pisces at the feet.
Aries rules the head, brain, skull, cranium, eyes, pituitary gland, and the adrenals.
Taurus rules the neck, mouth, jaw, throat, medulla and brain stem, larynx, thyroid, vagus nerve and vago-parasympathetic nervous system.
Gemini rules the chest, lungs, respiratory tract and nervous system.
Cancer rules the stomach, uterus, and female breasts.
Leo rules the heart, circulatory system, major arteries and thoracic spine.
Virgo rules the intestines, especially the duodenum and small intestine.
Libra rules the kidneys, lower back, genitourinary tract, and lumbar spine, as well as the hair, skin and all aesthetic body parts.
Scorpio rules the eliminative organs - colon, rectum and bladder, as well as the sexual organs, gonads and genitalia.
Sagittarius, the sign of long journeys, rules the locomotor aparatus - the hips, loins, thighs and buttocks, as well as the liver.
Capricorn rules the knees, bones and joints, the skeletal system and the structural connective tissue.
Aquarius rules the shins, calves and ankles, as well as the sympathetic nervous system and the peripheral vascular system.
Pisces rules the feet and lymphatic system.
Sign Symbolism and Body Parts
Each part of the body, according to its essential form and function, has a deep symbolic significance for the indwelling soul. The signs of the zodiac embody basic symbols or archetypes that resonate with the symbolic significance of the body parts they rule. These are as follows:
Aries: The charging ram. The head or soul / spirit that leads the body onwards.
Taurus: The mouth and throat: material appetites for acquisition and nourishment. The vegetative functions. The neck, which connects the Yang soul/spirit with the Yin material body, which gives it nourishment and sustenance.
Gemini: The dual-natured nervous and respiratory systems, which connect the soul / spirit with the material body.
Cancer: The house / home, womb or coccoon. The protective, nurturing space that stores, processes, ripens or grows things until they're ready to be released.
Leo: The lion, king of beasts, ruling the heart, king of organs, which radiates Life and heat outwards through the blood like the Sun. The thoracic spine, which enables us to stand regally proud and erect.
Virgo: Mutable or changing Earth worked on to be valuable nourishment. The intestines - the body's food processing plant.
Libra: The kidneys, which balance fluids and electrolytes. The genitourinary tract, through which a man plugs into his mate or partner.
Scorpio: The eliminative organs: elimination as a necessary prelude to transformation. The reproductive organs, handling life and death.
Sagittarius: The locomotor aparatus, which takes us on long journeys and explorations.
Capricorn: The bones and joints, which give solid structure (Earth) and functional usefulness to the body. The knees, which must bend in humility.
Aquarius: The peripheral vascular and veinous system, which returns blood back to the heart, ruled by opposing Leo.
Pisces: The lymph, the body's fluid recycling system, resonates with Pisces, the last sign, which ends and recycles the wheel of the zodiac. The feet, which must stay firmly rooted on the ground to anchor ethereal Pisces.