Venesection, or bloodletting (al-fasd)

Venesection (al-fasd), the opening of a vein to draw blood, is one of the manual operations that Ibn Sina in the Canon places third among the modes of treatment, after regimen and drugs ³. Chapter 20 of the fourth fann of Book I is devoted to it. He defines it as a general evacuation meant to relieve a plethora, and a plethora, for him, is an increase of the humours in the body ⁴. This record reports what Ibn Sina said and what was known to the medicine of his time; it is history of medicine, not treatment advice.

Ibn Sina says that two kinds of people should be bled: those prone to diseases that fall upon them when their blood increases, and those already suffering them; the bleeding may be for the quantity of the blood, for its badness, or for both. Among those prone he lists people liable to sciatica, gout, joint pains and spitting of blood, and people whose habitual flow of blood has been interrupted ⁵. He adds that someone who has taken a blow or a fall may be bled as a precaution against swelling, that bleeding should not be done on the day the disease is stirring, and that in a disease with crises in its course a great quantity of blood must never be drawn: a little is taken and some is left in the body to help the patient meet the crisis ⁵.

The Canon distinguishes the narrow cut from the wide one. The narrow cut preserves strength but may let the clear blood flow while the thick, dark blood is held back; the wide cut brings fainting sooner, cleanses more and heals more slowly. He prefers widening in winter and narrowing in summer, and has the patient lie on his back to keep his strength ⁶. For fevers he sets out detailed conditions: avoid bleeding in the most inflamed fevers and, at their onset, in fevers that are not acute, and look at the urine flask, the pulse and the complexion before acting ⁶. He lists those to be bled with caution: children under fourteen and the very old unless their physique shows strength, the very thin and the very fat, and those whose stomach is full of food ⁷.

Ibn Sina holds that several smaller bleedings suit better than one large one, and that a bleeding that was not needed stirs up bile ⁸. He describes the tathniya, a second letting of blood through the same cut after an interval, whose use is to keep the patient's strength while the necessary evacuation is completed; it is best put off for two or three days. Afterwards the patient should not fill himself with food, should return to normal diet gradually, and should avoid exercise and a bath that dissolves ⁸.

The Canon counts six veins of the arm that are opened: the cephalic, the median cubital (al-akhal), the basilic, the funis brachii (habl al-dhira), the salvatella (al-asilam) and the axillary, and it describes how each is cut. Arteries are opened rarely, and the danger is haemorrhage; even with a very narrow cut, the least harm is an aneurysm, a blood-filled swelling of the arterial wall ⁹. Under the median cubital vein lies a nerve, so it is best cut lengthwise; the basilic is very dangerous because an artery lies beneath it. The sign that an artery has been struck is thin, yellowish blood that leaps out, and for that case he gives a way of staunching it with rabbit fur and astringents and binding the arm for three days ¹⁰. He then tells that Galen, ordered in a dream to open an artery on the back of the hand for a pain in his liver, did so and recovered; Ibn Sina adds that a true dream is one part of prophecy ¹¹.

The Canon takes up cupping in chapter 21 and leeches in chapter 22, so for Ibn Sina venesection is a separate operation ¹². Cupping has its own record in the museum: Cupping (hijama). See also Treatment in the Canon and Surgery, the work of the hand.