Anatomy and Physiology
It is believed that the ancient Greek physicians knew the paths of blood in the human body. However, there was a question about how the blood flows from the right ventricle of the heart into the left ventricle, before the blood is pumped to the rest of the body. Galen mentioned in the second century AD that blood reaches the left ventricle through invisible paths in the interventricular septum. In the thirteenth century AD, Ibn al-Nafis considered that Galen's hypothesis wrong, after he discovered that the ventricular septum could not be penetrated, and it did not have any kind of invisible passages, which refutes Galen's assumption. Instead, Ibn al-Nafis discovered that the transmission of blood from the right ventricle to the left ventricle is via the lungs, which is known as the pulmonary circulation. However, his writings on this discovery were not discovered until the twentieth century, and William Harvey had independently discovered this theory centuries after Ibn Al-Nafis.
Ibn Abi Al-Ash'ath also described the functions of the stomach on a live lion, in his book Al-Ghadi and Al-Mughtadi. Where he wrote:
“When food enters the stomach, especially when it is full, the stomach expands and its layers expand... The one who looks at the stomach sees it rather small, so she proceeded to pour jug after jug into her mouth... The inner layer of the distended stomach became soft as the outer layer of the peritoneum. Then I cut the stomach and allowed the water to come out, so the stomach shrank until I saw its mouth.”
Ibn Abi al-Ash'ath wrote down his observations in 959, and some 900 years later, William Beaumont re-described these functions, making Ibn Abi al-Ash'ath a pioneer in experimental physiology.
Galen mentioned in his book De ossibus ad tirones, that the lower jaw consists of two parts, which can be proven when cooked, it is divided in the middle. While Muwaffaq al-Din Abd al-Latif al-Baghdadi was on a visit to Egypt, he came across several skeletal remains of people who had died of starvation near Cairo. Al-Baghdadi examined the structures, and concluded that the lower jaw consisted of one piece, not two, as Galen thought. He also wrote in his book “Evidence and Consideration in Observed Things and Observed Events in the Land of Egypt”:
“What I saw in this part of the corpses convinced me that the bones of the lower jaw were in one piece, without joint or joint. I have repeated the examination many times on more than two thousand heads... Many have helped me by repeating the same examinations, whether in my absence or under my eyes...»
Unfortunately, no one who wrote about medicine was interested in Al-Baghdadi's discovery, perhaps because he wrote down his discovery in a book on the geography of Egypt. The reason for ignoring this discovery may be that scientists at that time did not accept the idea that the ideas of ancient authors were wrong.
Optometry and ophthalmology
The ancient Greeks believed that vision was caused by rays emitted from the eyes that allowed us to see things. In the eleventh century, Ibn al-Haytham contradicted that theory, and Ibn al-Haytham proved it wrong through an optical device. Ibn al-Haytham's anatomy of the eye helped lay the foundation for his theory about image formation, which he explained by projecting light rays through two mediums of different densities, meaning that he proved his theory with laboratory experiments. In the following century, his corresponding book was translated into Latin, and it was taught in the Islamic world and Europe alike, until the seventeenth century.
Muslim doctors have shined in ophthalmology in particular, relying on what Ibn al-Haytham left in this field of works that remained a reference in this field until the beginning of the modern era. Charles Singer says: “Ibn al-Haytham’s book on optics is far ahead of the Greek science in this matter, and it has no equivalent at all among all Greek writings.”
Muslims also studied the eyes of animals, and learned from them that the movement of the eyeball is caused by the contraction of the eye muscles, while the movement of the pupil is caused by the contraction and relaxation of the iris. Ali bin Isa Al-Kahhal wrote a book called “A Treatise on the Anatomy of the Eye and its Outward and Internal Diseases,” which was translated into Latin, and had an impact on the science of ophthalmology in Europe in the Middle Ages. Salah al-Din bin Yusuf al-Kahhal also wrote his book “Nour al-‘Uyun wa Jami’ al-Funun,” which is considered the largest comprehensive reference in eye diseases. and the medications used to treat it.
Surgery was important in the treatment of incurable eye diseases such as trachoma and cataracts. A common complication of trachoma is an injury to tissues in the cornea of the eye, and Muslim doctors believed that this injury was the cause of the disease, so they resorted to surgical curettage of these tissues. They were doing that surgery by “using a device that keeps the eye open during surgery, and a very thin scalpel for excision.” Another technique that was used to treat complications of trachoma, called “pterygium”, was used to remove the triangular parts of the bulbar conjunctiva on cornea. This surgery was done by lifting the affected part with small hooks, then cutting with a small scalpel. Both surgeries were extremely painful for the patients and complicated to perform for the doctor or his assistants.
Muslim doctors believed that cataracts were caused by the fluid membrane that lay between the lens and the pupil. The surgery is done by making a small incision in the white of the eye with a scalpel, and inserting a thin tube to push the cataract aside. After the surgery is over, the eye is washed with saline solution and bandaged with a piece of cotton dipped in a solution of rose oil and egg white. There was concern that the cataracts from the side would reoccur after the operation, so patients were advised to lie on their backs for several days after surgery.
surgery
The growth and spread of hospitals in the Islamic world in the past contributed to the spread of the practice of surgery, as doctors were aware of how to perform surgeries due to the spread of medical writings that include a description of how to perform those surgeries. Muslims took translations of ancient medical writings as a basis for spreading surgical practices. Doctors did not favor the surgery due to its relatively poor success rates. Muslims excelled in many surgeries, such as splinting, bladder incision, and hernia, in addition to cupping and cautery, which were among the common therapeutic methods used by Muslim doctors in the past, and they were widely used to treat many diseases. They used cautery with a metal rod to stop bleeding from wounds and protect them from infection. They also wrote medical books that describe surgical operations and how to perform them. They even had their own surgical inventions, such as those made by Al-Zahrawi and drawn in his book “Al-Tasrif for those who are unable to compose,” which amounted to 200 surgical tools, and surgical sutures that they made from the intestines of cats and other animals.
As for cupping, it was used to remove bad mixtures from the patient's body. They also used bloodletting to remove blood directly from the veins. Cupping was either a “wet cupping” done by making a simple incision in the skin and drawing blood with a warm cup. The heat and suction to the glass cause the blood to come up to the surface of the skin and remove it. As for “dry cupping,” it is done using a hot cup without cutting the skin, in certain areas of the patient’s body to relieve pain, itching, and other common diseases. These operations sometimes caused injuries and possibly death of the patient, as a result of negligence during the incision.