Quick answer: The Part of Sickness is a calculated point in traditional medical astrology, not a planet. Found by projecting the arc between Mars and Saturn from the Ascendant (commonly Ascendant + Mars - Saturn), it symbolizes an area of physical vulnerability. It describes classical symbolism for reflection, never a diagnosis or prediction.
Traditional medical astrology kept a large catalogue of calculated points for studying the body, and the Part of Sickness is one of them. What follows describes how classical and medieval authors built and read it, offered as historical craft rather than health guidance.
What the Part of Sickness Actually Is
A Lot, called klēros in Greek and pars in Latin before the later name Arabic Part, is a sensitive degree derived by arithmetic, not a physical body. You measure the arc between two chart factors and project it forward from a third point, almost always the Ascendant, then reduce the result to a longitude between 0 and 360 degrees. The Part of Sickness is constructed from the two traditional malefics, Saturn and Mars, the classical significators of affliction. It is not one of the seven canonical Hermetic lots such as the Part of Fortune, Spirit or Eros; it belongs to the wider medieval catalogue compiled by authors like Al-Biruni and Bonatti.
Why the Formula Is Disputed
The most commonly cited formula is Ascendant + Mars - Saturn, yet the tradition does not speak with one voice. Some authors reverse the two malefics to Ascendant + Saturn - Mars, and others hold that the arc should reverse between a day chart and a night chart, as many lots do by sect. Because these disagreements were never settled, no single equation is universally canonical, and the point is best treated as a disputed technique rather than a fixed number. For contrast, the Part of Fortune is fixed and safe to cite as a model: Ascendant + Moon - Sun by day, reversed to Ascendant + Sun - Moon by night. The two malefics were chosen because Saturn, cold and dry, traditionally signified chronic, wasting and obstructive conditions, while Mars, hot and dry, signified acute fevers, inflammation and injury.
Reading the Point: Sign, Lord and Afflictions
Traditional reading proceeds by whole-sign method, so the sign the Part occupies is its place. That sign is mapped to a body region by zodiacal melothesia, the "Man of the Signs" that runs head to toe. The domicile lord of that sign is then examined, since its condition colors the whole significator, which is where a study of planetary dignities becomes useful. Only the five Ptolemaic aspects are used: conjunction, sextile, square, trine and opposition. Aspects from the malefics are read as aggravating, and aspects from the benefics Jupiter and Venus as mitigating.
| Sign | Body region governed | Domicile ruler | Humoral quality | | --- | --- | --- | --- | | Aries | Head, face | Mars | Fire, hot-dry (choleric) | | Taurus | Neck, throat | Venus | Earth, cold-dry (melancholic) | | Gemini | Shoulders, arms, lungs | Mercury | Air, hot-moist (sanguine) | | Cancer | Chest, breast, stomach | Moon | Water, cold-moist (phlegmatic) | | Leo | Heart, upper back | Sun | Fire, hot-dry (choleric) | | Virgo | Belly, intestines, bowels | Mercury | Earth, cold-dry (melancholic) | | Libra | Kidneys, lower back | Venus | Air, hot-moist (sanguine) | | Scorpio | Genitals, bladder, excretory | Mars | Water, cold-moist (phlegmatic) | | Sagittarius | Hips, thighs | Jupiter | Fire, hot-dry (choleric) | | Capricorn | Knees | Saturn | Earth, cold-dry (melancholic) | | Aquarius | Calves, ankles | Saturn | Air, hot-moist (sanguine) | | Pisces | Feet | Jupiter | Water, cold-moist (phlegmatic) |
This table is historical symbolism from the classical tradition. It does not correspond to any real medical assessment of the body or its organs.
Never Read Alone: the 6th House and the Luminaries
No traditional physician judged this point in isolation. The Ascendant and its lord signify the body and constitution, the Sun signifies the vital force, and the Moon signifies the body and, in decumbiture, the course of the illness. The sixth house of health is the classical house of illness and the joy of Mars, while the twelfth, the joy of Saturn, was linked to chronic and hidden complaints. The Part of Sickness adds one symbolic thread to this weave; it never overrides the rest.
From Hellenistic Lots to Culpeper's Decumbiture
The Lots reach back to Hellenistic astrology. Vettius Valens described many of them in his Anthology in the second century, and named the sixth place Bad Fortune and the twelfth Bad Daimon. The medieval catalogue grew under Al-Biruni, whose Book of Instruction (around 1029) lists a large body of parts, and under Guido Bonatti in the thirteenth century. The medical thread reached English readers through Nicholas Culpeper, whose 1655 work on the decumbiture of the sick set out how to cast a chart for the moment a patient takes to bed and to watch the Moon's motion to aspects for the "critical days."
A Symbol, Not a Diagnosis
This describes structure, not outcome. A challenging Part of Sickness does not mean someone is ill or will become ill, and an unafflicted one is not a certificate of health. The point marks a symbolic theme for reflection, drawn from a historical craft, and nothing in it can diagnose, screen for, or rule out any condition, or predict that illness will occur. For any health concern, consult a qualified medical professional; astrology and medicine are separate domains, and only the latter can assess your body.
Frequently Asked Questions
Is the Part of Sickness the same as the sixth house?
No. The sixth house is a division of the chart traditionally assigned to illness, while the Part of Sickness is a single calculated degree derived from Mars and Saturn. Traditional practice reads them together, the house as the general place of disease and the Part as one symbolic marker within the wider picture.
Which formula should I use?
There is no universally agreed formula. The most commonly cited is Ascendant + Mars - Saturn, but some authors reverse the malefics and some reverse the arc by day or night. Because the sources disagree, it is fair to calculate more than one version and treat each as a study exercise rather than a fixed result.
Can it predict an illness?
No. The Part is a descriptive-symbolic device, not a forecast. It cannot tell you that you are sick, will fall sick, or are safe. It describes a theme the tradition associated with vulnerability, offered for reflection and historical study, never as a medical prediction.
Does the sign really correspond to that body part?
Zodiacal melothesia is a symbolic system, not anatomy. The head-to-toe mapping of signs to body regions is a classical convention for reading charts, and it does not correspond to any real assessment of your body or its organs.
Explore the Symbolism for Yourself
To see where these points and houses fall in your own chart, cast a free birth chart and study the classical placements described above, or go deeper with a personality report. For more traditional technique explained plainly, browse the blog, and remember that all of it is a language of symbol and theme, never a substitute for medical care.
