Bone Elongation

| - osteoblasts begin to replace the fibrocartilage splint with spongy and compact bone, forming a bulge that is initially wider than the original bony shaft

One of the key elements of regulating skeletal growth is the Osteoclasts. The Osteoclasts are responsible for initiating the bone remodeling cycle. Blood vessels and nerves are able to penetrate the bone once the chondrocytes die

Materials for this laboratory included Microsoft excel to compile data, a pen and paper to record data, a 15cm ruler, string, a caliper, and a two meter ruler. Since bones often times vary in width in certain portions of the same bone due to the presence of joints and processes the bone was measured at the midpoint along its length for its true width. Measurements

Longitudinal bone growth occurs at the epiphyseal plate, which is a thin layer of cartilage between the epiphyseal and metaphyseal bone at the distal ends of the long bones. Bone growth is the result of maturation, growth of chondrocytes, their production of bone matrix, and finally calcification (47). The growth plate is a complex structure consisting of different layers of cells, as shown in figure 3. The most immature cells, the stem cells, are found towards the epiphyseal end of the growth plate in the stem cell zone, or resting zone; the proliferating zone contains more mature chondrocytes and the hypertrophic zone contains the larger chondrocytes. The resting stem cells in the resting zone are recruited, whereupon proliferation and differentiation

Each long bone has at least two growth plates. There is one at each end. The growth plate

The process of bone development and bone growth, as well as maintaining healthy bones, is dependent upon several hormones produced in the body. The hormone Calcitriol, which is produced in the kidneys, plays a key role in the absorption of calcium and phosphate ions within the digestive system. The pituitary gland is responsible for the Growth hormone. It causes the building up of the bones, producing bone growth. The development of the hormone Thyroxine comes from the thyroid gland. Thyroxine prompts the cells metabolism and it increases the activity of bone growth. Together the Growth hormone and Thyroxine help maintain the normal growth of bones at the epiphyseal plate until the time of puberty. Upon reaching puberty there is a significant rise in the Sex hormones, estrogen and androgen.

There was a lot of information in this week’s reading. Having studied the skeletal system in previous classes, this was quite the refresher. Although I recognized a lot of the terms used to describe bones, it was very interesting to read about the basic anatomy of bones. In my reading of Bowers Chapter 2 page 46, I learned about the three anatomical categories of bone. I also learned about the three gross structures of long bones. In the past, I knew that the thigh bone was called a femur and that it was a long bone. I did not know that as along bone, its three parts were called the diaphysis, metaphysis, and epiphysis. This information was useful when I read the case study. Estimating age based on whether the epiphysis had fused or not was

(2009) suggested that stress on the pars interarticularis during infancy, early adulthood may be a reason for the development of dysplasia. Moreover, the ossification during the embryological state may not progress uniformly or there appears to be a transition between dense trabecular bone in the PI and the inferior articulating facet and less dense trabecular bone at the base of the pedicle only in the lower segments. Such abnormalities in tissue density may persist into childhood leading to a potential area of weakness.

A surgical procedure to limit the growth of a normal leg to allow a short leg to grow to a matching length is an Epiphysiodesis. An epiphysiodesis procedure using guided growth was first recorded in 1933 by Phemister to correct leg-length discrepancies and angular deformities of children.11 This procedure is performed on the epiphyseal plate in one of the patient's legs that slows down the growth of a specific bone and is performed under general anesthesia. A surgeon would make an incision over the epiphyseal plate shown in Figure 1 and at the end of the bone in the longer leg shown. Then proceed to destroy the epiphyseal plate by scraping or drilling a screw or stable to restrict further growth. The percutaneous technique uses the screw or

The end plates begin to fuse when the child is 14 to 15 years of age and may be confused with fractures until fusion occurs at 21 to 25 years of age.(13) Ossification of the growth plates (end plate) at the age of 7-8 years creates a groove at the corner of each vertebral body. This groove is circumferential around the upper and lower end plates of each vertebra. The ligaments and discs attach to this groove, which is therefore an apophyseal ring. The ring apophysis develops

To study the longitudinal growth of a long bone, Duhamel inserted needles at equal intervals into the femur of a newly-hatched chick. Dissection of the femur of the chick, fifteen days later, revealed the impressions made by the needles to be separated by various intervals, smallest nearest the trabecular region and largest nearest the cortical bone because hardening begins in the trabecular of the bone and gradually proceeds towards the cortical bone. This proved that the different portions of the bone do not all grow equally but the trabecular bone grow more than the cortical bone. This phenomenon is now known as longitudinal bone growth.

Bone arrangement is a vital procedure in the improvement of the human body. It begins amid the improvement of the hatchling, and proceeds all through youth and immaturity as the skeleton develops. Bone redesigning in the mean time is a long lasting procedure, comprising of resorption (the separating of old bone) and hardening (arrangement of new bone), and is vital to molding the skeleton and to the repair of bone

The epiphyseal plate is the area of growth in the long bone. There are four zones of cells and activity in the epiphyseal plate. First, zone of resting where the cartilage attaches to the epiphysis. Second, zone of proliferation where the new cartilage is produced on the epiphyseal side of the plates as the chondrocytes divide and form stacks of cells. Third, zone of hypertrophy where the chondrocytes mature and enlarge. Lastly, zone of calcification where the matrix is calcified and chondrocytes

When we think of bone it sounds like it is hard to grow and that is true too. Bones are the hardest components of our body. It is made of calcium laid down by stem cells. In children, cells at the end of epidermises add new calcium to the network of the bone and that grows over time. So, the children have that epiphyseal plate that grows and becomes narrow when they reach up to their adult height. The Ted talk by Molly Stevens on ‘A new way to grow bone’ was interesting. Where she talked how fracture bone repairs itself or we can repair by transplanting thick bone like an Iliac (pelvic bone) bone to the area of the

Bones function in our body by providing structural support, protection, attachment sites for muscles, mineral storage, fat storage, and even involved in the formation of blood cells. The two types of bone in our body are compact bone (which is found forming the outer layer of bones for protection and support) and spongy bone (which is composed of an unusual lattice of slender columns of bone termed trabeculae and in the spaces of the trabeculae red bone marrow can be found). Bones of made of three cells, osteoclasts which breaks down bone tissue, osteoblasts which secrete the matrix for bone creation osteocytes which are mature osteoblasts that have become stuck in the bone matrix. An important cycle that bone goes through, Bone Remodeling, is the process of old bone tissue being replaced by new bone tissue. This process involves 5 steps Activation, Resorption, Reversal, Formation, and Quiescence. The activation step involves the activation of stimulating of pre-osteoclasts and mature into active osteoclasts, the resorption phase in which the osteoclasts begin to digest old bone, the reversal stage involves the ending of resorption, formation then begins with osteoblasts forming a new bone matrix, and finally quiescence is when the osteoblasts become resting bone which line the cells on the freshly constructed bone surface.