İKİNCİ FEN · ÜÇÜNCÜ BÂB · BİRİNCİ FASIL · İkinci Madde
Second Article
Concerning some facial muscles and the movements that arise from them.
O, beloved! Know that anatomists have said: The facial muscles are in proportion to the number of movements of the mobile organs of the face.
The mobile organs of the face are: the forehead, the two eyes, the two upper eyelids, the two cheeks, the nostrils, the lower jaw, and the lips.
The movement of the forehead is accomplished by a thin, broad, and covering muscle. This muscle is so distributed beneath the skin of the forehead that the skin of the forehead is a portion of it, and its separation from it is impossible. The skin of the forehead reaches the moving organ through a tendon. With the contraction of this muscle, the eyelids open, and with its relaxation, they descend, also assisting in closing the eyes.
The pupil, which is within the eye, has six muscles that move it. Four are on the four sides of the eye, each moving the pupil towards itself. The remaining two are placed obliquely backwards. With them, circular movement of the eye is performed. Behind the pupil there is a muscle which will be explained later as being directly connected to the optic nerve and providing it with firmness through its membranes. And it prevents and holds back the eyeball from bulging outwards.
The purpose is achieved solely by the movement of the upper eyelid; since closing, opening, and looking are accomplished in the most beautiful way, there is no need for the movement of the lower lid. The grace of the Most High tends to accomplish tasks with as few instruments as possible, for as the instruments increase, so too does misfortune and calamity. The upper eyelid could have been motionless, and the lower lid movable. But the wise Creator’s intention is directed towards accomplishing things near their original sources. Since the upper eyelid is close to the exit point of the nerves, it is known that they do not need to turn or bend when they reach it.
For the upper eyelid, an upward movement is required during opening and a downward movement during closing; and since the lower lid requires muscles to draw it downwards, two muscles have been created on either side of the eye which are found drawing the lower lid downwards. A muscle descends into the middle of the eye for its opening, and its tendon spreads towards the side of the lid, so that when it is stretched and pulled, the eye opens. For this, a muscle has been created that descends straight down. A body like cartilage extends horizontally between the two membranes of the eyelid, spreading beneath the place where the eyelashes emerge. The eyelid has been created to protect the pupil, and the eyelashes to protect it from dust. That is to say, all parts of the body have been created for numerous wisdoms and benefits.
“We glorify the Exalted Creator who fashioned all these things with skill and form, free from every imperfection. His glory is exalted.”