Craniofacial Growth and Development Lecture 2 PDF

Craniofacial growth and Development Lecture 2  Growth 1. Pattern of growth 2. Type of growth 3. Phases of growth 4. Differential growth Scammon’s growth curve Cephalic-caudal gradient of growth 5. Growth spurt  Infancy It comprises the first...

Craniofacial growth and Development Lecture 2  Growth 1. Pattern of growth 2. Type of growth 3. Phases of growth 4. Differential growth Scammon’s growth curve Cephalic-caudal gradient of growth 5. Growth spurt  Infancy It comprises the first year of life. This is a period of rapid growth in most body systems and dimensions and rapid development of the neuromuscular system. Immediately after birth, the rate of growth increases. In case of weight, the peak velocity is reached at 2 months after birth. More than 50 % of birth length and 200 % of birth weight take place during the first year of life.  Childhood It starts from the end of infancy till the start of adolescence. Childhood is a period of relatively steady progress in growth and maturation and rapid progress in neuromuscular or motor development.  Childhood Early Middle Late childhood childhood childhood  Adolescence The adolescence period extends from the time of puberty up to around 20 years. In this period of life, the hormonal influences play a leading role in order to attain sexual maturity. There are changes in the reproductive organs, in body size and shape, in the relative proportions of muscle, fat and bone and in a variety of physiological functions.  Adolescence During this period there is a marked acceleration of growth which is known as "adolescence growth spurt". Adolescence growth spurt: In boys it takes place, on the average from age 12 to 15 years while in girls, it begins about two years earlier.  Growth 1. Pattern of growth 2. Type of growth 3. Phases of growth 4. Differential growth Scammon’s growth curve Cephalic-caudal gradient of growth 5. Growth spurt  Differential Growth Not all system of tissue body grow at the same rate. Different tissues and different organs grow at different rate. This process is called differential growth  Scammon’s growth curve Growth of the neural tissue is (the main tissue component of the nervous system) is nearly complete by age 6, 7 yrs  Scammon’s growth curve Growth of the general tissue like bone, muscle, viscera show S-shaped curve with a slow rate during childhood and an acceleration at puberty  Scammon’s growth curve lymphoid tissue (organized structures that support immune responses) proliferate far beyond the adult amount in childhood and then undergo regression at the same time that growth of genital tissues accelerate rapidly N.B. primary lymphoid tissues: The bone marrow and thymus. secondary lymphoid tissue: lymph nodes, spleen, tonsils.  Changes in proportions of craniofacial region At birth, the face is less developed and the cranium representing more than half of the total head. N.B.: Cranium is part of the skull, especially the part enclosing the brain.  Changes in proportions of craniofacial region Maxilla is closer to the brain/head grows faster and its growth is completed before the mandible. Maxilla Mandible  Significance of scammon’s curve in the facial region Maxilla and mandible growth is intermediate between neural and general curve Skeletal problems should be treated earlier in maxilla or in mandible?  Significance of scammon’s curve in the facial region Q Skeletal problems should be treated earlier in maxilla or mandible? Maxilla follow neural growth pattern and its growth ceases earlier in life. Skeletal problems of the maxilla should be treated earlier than that of the mandible Example: growth modification procedure as face mask should be given earlier in life (6 yrs) to promote maxilla growth.  Significance of scammon’s curve in the facial region Mandible follow general growth pattern and its growth occurs until about 18-20yrs Chin cup Class III malocclusion Example: growth modification procedure as chin cup should be extended until cessation of mandibular growth so as to prevent relapse of class III malocclusion due to continued growth of the mandible.  Growth 1. Pattern of growth 2. Type of growth 3. Phases of growth 4. Differential growth Scammon’s growth curve Cephalic-caudal gradient of growth 5. Growth spurt  Cephalic-caudal gradient of growth Represent the changes in overall body proportions during normal growth and development. In fetal life (3rd months I.U.L.), The head takes up to 50% of the total body length. The cranium is large relative to the face and represent more than the half of the total head.  Cephalic-caudal gradient of growth The limbs are still rudimentary and the trunk is under developed. By time, the trunk and the limp have grown faster than the head and the face. The overall pattern of growth follow this course, with a progressive reduction of the relative size of the head to about 12% the adult. Thus, cephalic-caudal gradient of growth, which means there is an axis of increased growth extending from head towards the feet