İKİNCİ FEN · ÜÇÜNCÜ BÂB · ÜÇÜNCÜ FASIL · Dördüncü Madde
**Fourth Article**
Concerning the muscles and movements of the thigh.
Know, esteemed one, that the anatomists have said: The muscle which moves the thigh is the largest, and it is the muscle that opens its joints. The others fasten and hold it in place. For the most important function of the thigh is opening and bending. Man stands by the opening of the leg, so opening is more important than bending. Following these are the sitting muscles. Then come the muscles which draw the thigh towards the body. After them are those that turn the thigh to the rear.
The largest muscle that opens the thigh joint is also the largest of the bodily muscles. For it encompasses the seat bone and pubes, extending toward the back and inner side of the thigh as far as the kneecap, and its fibers have different origins and therefore different functions. Some of its fibers originate from beneath the pubic bone, inclining towards the inner side of the thigh and dispersing. Some originate from the upper parts of the thigh, raising the leg. Some originate higher still, inclining inwards and lifting it. Some originate in front of the pubic bone joint, opening the thigh straightly. One muscle encircles the pubic bone joint from behind, spreading the leg straightly. The origins of these three muscles are from the flanks, seat bone, and coccyx—that is, the bone at that place. Two of these three muscles are fleshy, while one is membranous.
All of these tendons originate from the head of the thigh, attached to its rear. If one of these muscles contracts, it draws the leg towards itself, opening it. If it pulls with both sides, it spreads the thigh straightly. And the origin of one lies on the entire outer side of the firm will, abutting the upper part of the great prominence and extending a little forward, drawing the thigh outwards. Similarly, the muscles first originate from its lower projection, descending from it and performing what the previous muscles do. The difference in this muscle is that it bends and curls the leg more than straightening and raising it. There is another muscle originating from the lower part of the seat bone, inclined towards the middle and spreading, which opens the leg with a slight curve outwards and a larger curve inwards.
One of the muscles that flexes the leg bends the thigh inward and causes a moderate rotational movement. This is a straight muscle, originating from the seat bone and descending from it, one tendon attaching to the end of the solid bone and the other to the lesser prominence. Another muscle originates from the firm will and attaches to the lower part of the lesser prominence. A third muscle extends with an inclination towards the vicinity of the second, becoming like a portion of the great prominence. The fourth muscle originates straightly from the front part of the firm will, grasping the leg and bending the thigh. Some of the muscles that draw the leg inward have been explained in connection with the muscles that move the leg.
However, there is another special muscle for this type of movement which originates from the firm will, a long muscle extending as far as the knee. There are two special muscles that draw the leg outwards, whose origins are from the broad prominence. Two muscles also turn the leg backwards, one originating from the outer side of the pubic bone and the other from its inner side, intertwining with each other and becoming fleshy in the hollow on the back side of the great prominence. Whichever of these draws the leg alone turns it towards itself with a slight opening of the thigh. If they both pull together, the leg is drawn straight backwards. Whoever contemplates these things with awe will find the wondrous power and artistry of the Exalted God.
“We glorify Allah, the Living One, whose non-existence cannot be conceived, far removed from all imperfection.”