THE ROLE OF GROWTH PLATES IN GROWTH OF LONG BONES
Bones grow long after a rapid production chondrocytes in the growth plates of the long bones.
Hence, to prolong the duration for longitudinal bone growth during puberty, to prevent growth plates from closing or keeping growth plates open by delaying their closure should be a necessity.
With this article you will discover a few facts about growth plates like; how to check if growth plates are still open and when growth plates close.
what exactly are growth plates?
Simply put, the epiphyseal / growth plates are thin layers of cartilage disc entrapped at the distal ends of long bones between the epiphysis (head ) and metaphysis .
There’re two growth plates in all long bones with one located at each end of the long bone.
A cartilage is formed at the growth plate area, then hardened by deposition of calcium thus forming bone tissue.
The newly formed bone tissue is what contributes to bone length and this process continues until the growth plate cartilage ossifies to become bone and closes.
The growth plate is therefore the location where growth in long bones takes place.
Bones that have growth plates in human body
Like earlier mentioned, growth plates are located in long bones.
Examples of the long bones with growth plates include the shin bone, back bones, the femur (thighbone), the radius and ulna in the forearm, as well as the metacarpal bones in the hands.
How to check if Growth Plates are still open
X- ray scans can be taken for bones under investigation to check if growth plates are still open at home or hospital.
X – ray showing Open and Closed plates.
How Growth takes place at the Epiphyseal Plate.
In brief, skeletal growth at the epiphyseal plate is active and constantly changing.
There is the bony part, the fibrous and cartilaginous part among other features that make up the growth plate.
All the above mentioned features co-ordinate during the process of bone growth and or lengthening .
The cells found in growth plate cartilage manufacture a template which is the foundation on which bone forms.
Immature (stem-like) chondrocytes begin by multiplying rapidly, they mature and and finally die, there by forming new bone tissue to on the remaining cartilage matrix.
For details on how bone growth is mediated in the growth plate zone, visit how long bones grow.
How about Flat Bones? How do they grow?
Flat bones like the skull don’t grow from the cartilage.
They are rather structured by osteoblasts as they develop.
Osteoblasts are the cells that make bone by producing a matrix that then becomes mineralized.
Cells in bones of the skull modify to become osteoblasts.
The osteoblasts then manufacture collagen and create soft bone which is broken down by osteoblasts to manufacture the flat bones.
How and why growth plates close
It is suggested that as we grow older, less growth plates cells are manufactured until the time comes when no more cells are manufactured towards the end of puberty.
Remember, the old cells die and become bone hence, considering that time comes when there’s no more proliferation of new cells, with time growth plate is eventually filled with the dead cells which become bone thereby closing the growth plates.
Estrogen hormone speeds up the process of cell depletion which partly explains why girls stop growing earlier than boys.
Estrogen which is the predominant female hormone is secreted in great amounts during puberty especially when girls begin ovulating.
This hypothesis was tested and proved after inoculating rabbits with estradiol cypionate for 5 weeks which reduced the height of the growth plate cartilage and the number of reproductive cartilage cells.
Estradiol is the most predominant estrogen out of the three naturally occurring estrogens produced in the body.
The other two being estrone, and estriol.
The main role of estradiol is to regulate the female menstrual cycles and reproductive system as well as development of sexual features like widening of hips and breast development.
Among males, estradiol regulates sexual desire, sperm production and erectile function.
Towards the end of puberty, estradiol production increases though levels are higher in females than in males.
Thus it’s the heightened levels of estrogen secretion towards the end of puberty that accelerate or catalyze the fusion of the growth plate.
When do Growth Plates close or fuse?
This varies from person to person.
However, according Dr. Andre C. Grant, MD an orthopaedic surgeon at Duke Orthopaedics of Raleigh, most children stop growing approximately 2 years from end of pubertal growth spurt which normally ends at 14 for girls and 16-17 for boys.
This means that in most cases, growth plates close between 14 and 16 years for girls and between 16 and 19 years for boys.
In case of Precocious puberty where the child transforms to an adult earlier than expected, the growth plate closes earlier leading to short stature.
If a girl enters puberty before 8 years or if a boy enters puberty before 9 years, then that’s referred to as Precocious puberty.
However, the entire process of growth plate closure in humans is not fully known since what is known is based on animal studies yet majority of animals don’t have much in common with humans.
Rodents have some degree of correspondence with humans but their growth plates don’t fuse at the end of puberty.
Role played by hormones.
Growth hormones
G.H directly promotes bone lengthening by directly stimulating growth plates cartilage cells.
Administering growth hormones directly on tibia growth plate cartilage of rats whose pituitary gland was removed rapidly increased the rate at which the bone lengthened.
This is because G.H arouses inactive growth plate cells to multiply rapidly there by forming new bone tissue.
Estrogen
Estrogen hormone increases the rate at which bones mature and accelerates the rate at which growth plates close.
Among girls whose predicted adult height is estimated to be extremely tall, estrogen is administered to limit bone growth.
Hence, like earlier mentioned an increase in levels of estrogen secretion when the girl menstruates for the first time is partly the reason why girls stop growing within approximately 2 years from the time they get their first period.
How to prevent or delay growth plates from closing if you are still in puberty (how to keep them open naturally)
1. Resveratrol supplementation
Resveratrol is a substance produced by plant tissues when the plant is attacked by parasites or injured.
Resveratrol supplements have a number of health benefits in humans including cutting down on blood fats.
In an experiment that aimed to evaluate the long-term effects of resveratrol on growth plate cartilage, bone growth and growth plate fusion, pre-pubertal female rabbits were used.
Rabbits were chosen because the timing of growth plate fusion in rabbits normally occurs at the time of sexual maturation, just like in humans unlike in small rodents.
Resveratrol treatment in rabbits improved longitudinal bone growth and delayed growth plate closure.
It was concluded that resveratrol has the potential to improve longitudinal bone growth.
The impact of resveratrol on enhanced growth of the long bones was attributed to a delay of growth plate fusion resulting in an increase of the final bone length. [1 ]
2.Tamoxifen (Nolvadex)
A drug used to treat the enlargement or swelling of breasts among men.
This condition is normally a result of too much secretion of estrogen hormone compared to testosterone in men.
Estrogen is a female sex hormone responsible for development of sexual and reproductive features in women breasts inclusive.
Tamoxifen is also used to treat breast cancer in both men and women.
When short teenage boys who were still in puberty with an average age of 14 – 15 years were administered with 10 – 20mg of tamoxifen twice everyday for an average of 26 months, their skeletal bones matured very slowly which slowed down the closure of their growth plates thus increasing their predicted adult height average by approximately 10 cm.[2]
3. Aromatase inhibitors
Aromatase is an enzyme responsible for estrogen synthesis by converting androgens to estrogen.
Androgens are hormones responsible for male characteristics.
For instance testosterone.
Aromatase inhibitors are drugs that hinder the secretion of estrogen hormone.
They are also used to treat cancer among older women.
such drugs include Letrozole, Aomasin and Arimidex.
When puberty ends, male and female reproductive glands secrete estrogen hormone in higher quantities.
Estrogen then speeds up the process of growth plates closure.
Thus, since aromatase inhibitors inhibit estrogen production, closure of growth plates will be delayed by the drugs [3]
Heads Up!
All medications and supplements should be used under strict medical supervision.
If you are past the puberty stage or your growth plates are closed but still wish to grow taller, you should read The Grow Taller After Puberty Exercise Routine Guide »»»
AUTHOR BIO
As a short guy who was psychologically distressed almost everyday due to the challenges he faced in life accountable to his height, Dennis Raney (Bsc.) finally somehow found a way to overcome this adversity by naturally increasing his height with lifestyle and healthy changes.
He has been researching this topic for over a decade and practically applying the knowledge so he decided to share his wealth of information about the topic of increasing height both during and after puberty in the book and on this blog.
Feel free to connect with him for a conversation:
Email: Dennis »»
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