İKİNCİ FEN · İKİNCİ BÂB · BİRİNCİ FASIL · Beşinci Madde
Fifth Article
It declares the benefits of the nose, the anatomy of its bones, and the lower jaw.
O Noble One! Know that anatomists have said: The nose possesses many apparent and known benefits. And among them is that with its cavity it aids in drawing water inward. Another is that it purifies the air before it reaches the brain, taking in much air. For while some of the air drawn into the nose reaches the brain, most descends to the depths of the lungs. Another benefit is that it gathers the air suitable for smelling, located near the organ of smell, thereby enhancing perception and making it more effective. A further benefit is that it assists in the modulation and easy pronunciation of letters; thus, not all the air in the section where letters are modulated becomes constricted. Another benefit is that it retains the secretion descending from the head and shields it from the eyes. Another is that it aids by expelling this secretion. The nasal bones consist of two triangular-shaped bones, whose angles join at their upper side. Their two bases unite at an angle, separating them into two angles. Each of these two bones settles and extends to one of the facial sutures on either side. At their lower sides are two soft cartilages. Between them is a cartilage that spans the length of the middle suture; its upper portion is harder than its lower portion, and it is harder than all the cartilages on both sides. The benefit of this central cartilage is that it has made the nose, which is like a fountain for bodily secretions, into two openings. Thus, when the secretion descends from the brain and reaches the nose, it mostly directs itself to one of the two openings, preventing it from completely blocking the path by which air, pleasing to the spirit residing in the brain, is drawn. The benefit of the cartilages on either side is threefold: One benefit is identical to that of the cartilages surrounding other bones. Another is that when there is a great need for air, they open and expand. And another is that they assist in expelling vapor through trembling and tension during breathing. The two bones of the nose are created light and thin, because their need is for lightness rather than strength. The appearance of the lower jaw bones is arranged according to a specific order, for the lower jaw consists of two bones. A strong joint unites them beneath the place where the two jaws join. Their two ends rise on two high, curved bones, joining with protrusions that interlock with ligaments upon one another. There are many benefits that require no elaboration, such as the opening of the mouth and the chewing of morsels through the movement of the lower jaw.