颅面部的生长发育(1)

The pattern of growth refers to the change in these spatial proportions over time. Figure illustrate the change in overall body proportions that occurs during normal growth and development. In fetal life, at about the third month of intrauterine development, the head takes up almost 50% of the total body length, the cranium is large relative to the face and represents more than half the total head.
By the time of birth, the trunk and limbs have grown faster than the head and face, so that the proportion of the entire body devoted to the head has decreased to about 30%. The overall pattern of growth thereafter follows this course, with a progressive reduction of the relative size of the head to about 12% of the adult.
１．生活环境的变迁；２．食物结构的变化；３．咀 嚼器官的不平衡退化．
遗传与个体发育（individual development)
An important aspect of pattern is its predictability. A change in growth pattern would indicate some alteration in the expected changes in body proportions.
颅面部生长发育知识的重要性
• 颅面部生长发育与错合畸形诊断及矫治计划
It is important to distinguish normal variation from the effects of abnormal or pathologic processes. Since dentists and orthodontists are heavily involved in the development of not just the dentition but the entire dentofacial complex, a conscientious practitioner may be able to manipulate facial growth for the benefit of the patient.
Of all these changes, which are a part of the normal growth pattern, reflect the “cephalocaudal gradient of growth”. This simply means that there is an axis of increased growth extending from the head toward the feet.
development is necessary for every dentist. Even for those Байду номын сангаасho never work with children, it is very difficult to comprehend conditions observed in adults without understanding the developmental processes that produced these problems.
一、概 述
（一）生长与发育的基本概念 Concepts of growth and development
The term growth usually refers to an increase in size or number. Development connotes an increasing degree of organization, an increase in complexity and specialization. Growth is largely an anatomic phenomenon, whereas development is physiologic and behavioral.
颅面部的生长发育
Growth and Development of The Craniofacial Complex
Liu yue-hua, Dept. of Orthodontics
颅面部生长发育知识的重要性
• 口腔医学的基础知识，也是口腔正畸学的重要基础知识。 • A thorough background in craniofacial growth and
A second important concept is variability. Obviously, everyone is not alike in one way that they grow as in everything else.
从胎儿2个月至25岁身体各部分比例变化（Robbins WJ， 1928）
（二）遗传与环境因素
• 遗 传(heredity) --决定性作用
• 环 境(environment factors) --
遗 传(heredity)
错合畸形是伴随着人类的种族演化（race evolution) 而发生和发展的．