medical

This article focuses on the theme of "why feet are not as agile as hands", and explains the background of the differentiation of hand and foot functions in the process of human evolution. It explains the reasons why feet are less agile than hands from the structural aspects such as joint range of motion and the differences in the form and function of fingers and toes. At the same time, it points out that although feet lack flexibility, they can support the stability of the body, and the agility of hands and feet is greatly influenced by acquired training and individual differences.

This article focuses on the question of "why people with flat feet tend to get tired easily when walking", introducing the structure and function of the arch of the foot and the principle that a normal arch is less prone to fatigue. It also explains the definition and causes of flat feet, the reasons why walking is tiring for people with flat feet, and describes the improvement and correction methods for different types of flat feet.

This article answers the question of why the five fingers of humans are of different lengths, pointing out that the different lengths of the five fingers are due to their respective specialized functions to meet different usage needs. Moreover, fingers of different lengths can cooperate with the transverse arch of the palm to expand the functions of the hand, adapting to various needs of life and work.

This article focuses on why people often experience a sore throat when they are unwell, introducing the structure of the throat and its immune defense mechanism, explaining the principle of a sore throat, methods of judging the severity of the condition, various causes of a sore throat, and the root causes of recurrent sore throats. It also describes the immune function of the tonsils and the precautions for their removal.

This article focuses on the question of "why children are prone to nosebleeds", introducing the structural characteristics of the nasal bleeding area in the anterior and inferior region of the nasal septum, explaining the reasons why children are more prone to nosebleeds due to their own characteristics such as having an allergic constitution, having unhealthy eating habits, and having weaker immunity, and describing the common occurrence sites, symptoms, and possible triggers of nosebleeds in children.

This article focuses on the question of why people have a runny nose, and introduces the physiological function of a runny nose, the causes of a runny nose in different scenarios, the harm of frequent runny nose, and the reference value of a runny nose in the diagnosis of nasal diseases

This article focuses on the issue of why improper use of headphones can damage hearing, introduces the working principle of the human auditory conduction pathway and the characteristics of inner ear hair cells, explains the mechanism of hearing damage caused by improper use of headphones, and provides relevant health and safety advice for people who like to use headphones.

This article explains why one's own voice may sound distorted, pointing out that the perceived distortion when listening to recordings is not solely due to the poor fidelity of the recording equipment. The core reason is that when we listen to our own voice, the sound is transmitted through a combination of two channels: air conduction and cranial conduction. However, when listening to recordings, the sound is only transmitted through the air conduction channel.

This article provides an answer to the question of "Can myopia and hyperopia occur simultaneously?" It points out that it's not the case that elderly people wearing glasses for myopia and glasses for presbyopia at the same time mean that myopia and hyperopia coexist. Presbyopia and hyperopia are completely different concepts. Only astigmatism is a case of true coexistence of myopia and hyperopia. It also introduces the causes of astigmatism and related knowledge about its correction.

This article focuses on the question of "why there are both true and false myopia", and introduces the different causes of true myopia and false myopia, the groups prone to false myopia, the triggering factors and related symptoms. It explains the origin and essence of the concept of false myopia and the harm of treating it as true myopia, and mentions the viewpoint put forward by ophthalmology experts that false myopia may be overhyped and that it is not appropriate to further distinguish between true and false myopia.

This article takes the core question of "Why are all people born with farsightedness?" as its starting point. It first introduces the refractive principle of the human eye and the causes of refractive abnormalities such as myopia and farsightedness. Then, it explains that people are born with farsightedness due to the shorter anterior-posterior diameter of the eyeball, and as they grow older, the refractive degree of farsightedness gradually decreases until around the age of 18, when they completely get rid of farsightedness. At the same time, it points out that preschool children with farsightedness are not easy to detect and often do not show obvious symptoms.

This article focuses on the topic of "Why do people cry?" and introduces two types of tears (emotional tears and reflexive tears), the composition and source of tears, the function of tears, as well as the secretion and excretion balance mechanism of tears and the causes of abnormal tears.