İKİNCİ FEN · İKİNCİ BÂB · ÜÇÜNCÜ FASIL · Altıncı Madde
Article Six
It describes the shinbone and knee joint.
O Noble One! Know that anatomists have said: Just as the forearm is created from two bones, so too is the shin composed of two. One is large, long, and on the upper side, to which they give the name *kasaba-i kubra* (larger bone). The other is small, short, and its upper portion does not reach the thighbone, and it is called *kasaba-i sughra* (smaller bone). Like the thighbone, a prominence has been found on the upper side of the shinbone. The *kasaba-i sughra*, however, is created in a hollowed form on the lower side, towards the inner aspect. Thus, the muscles and nerves of the shin are properly arranged with them. In truth, the first shinbone is the *kasaba-i ekber* (greater bone), which is found to be shorter than the thighbone, so that it may be light for movement. And this shinbone has been given a beautiful dimension, such that it is incapable of carrying what is above it, nor does it experience difficulty in moving. Despite this, it has also been granted strength and power through the *kasaba-i sughra*. Besides its own strength, the *kasaba-i sughra* also performs the duty of covering and protecting the nerves and vessels between them. It assists the *kasaba-i kubra* at the ankle joint, created to give it force in opening and closing movements.
The knee joint is formed by the two protrusions on the lower side of the thighbone entering the two cavities on the upper side of the shinbone, and these are connected by strong ligaments, firmly bound with two solid ligaments on each side. Their front aspects reside within the kneecap. The kneecap is a round bone prone to fracture, to which they give the name *ayn-i rukbe* (eye of the knee). The benefit of this being so is that it prevents the knee joint from dislocating when one sits on the knee, and the knee joint finds safety with this bone. It gives strength and support to the joint as it bears body weight. The location of this bone is on the front side of the joint, because stiffness and curvature in this joint are most often seen on its front aspect. Stiffness and curvature from the back are rare, and deviation to the sides is also seldom observed. Therefore, one should be careful not to strain the knee joint from the front during sudden standing and sitting.
“We praise and glorify Allah.”