Examples of irregular bones are those of the vertebra and some facial bones 10. Round bones are also called sesamoid bones i. They are small and modular and embedded in tendons ii. Example is the patella (kneecap) B. Parts of a long bone 1.
In addition, Trabecular Metal has an elastic nature which aids bone remodeling. 6. Polyethylene: The tibial and patellar components in knee replacements are made of polyethylene. Wear is less of a problem in knee implants as the bearing surfaces are flatter and do not result in the same kind of wear. The use of Ultra Highly Cross Linked Polyethylene (UHXLPE) or Ultra High Molecular Weight Polyethylene (UHMWPE) reduces even the minimal wear enabling the knee implants to last for a much longer time.
The tough compact bone is not needed in the middle therefore compressive and tearing forces cancel each other out mid-way through the bone. Question 5 Describe the microscopic features of osseous tissue that help long bones withstand compressive forces without breaking. The bony collar of long bones is the one that is designed to help support the weight of the body and withstand compressive stress. Epiphysis, is spherical in shape and is located at both the distal and proximal end of a long bone. It consists of an irregular latticework of needle-like threads of bone called trabeculae.
The skeletal system frames our entire bodies and protects our fragile inner organs. We have two major types of bone in our body: compact bone and spongy bone. Compact bone is dense and looks smooth, while spongy bone is comprised of small needle-like pieces of bone with lots of open spaces. Our body contains 206 bones. The skeleton is separated into axial and appendicular sections.
For each of different size of wheels, there is limitation for the load. It is important to understand the basic modes of fracture that are enable a crack to propagate. The three modes are opening mode (mode I), in-plane-shear (mode II) and out-of-plane-shea... ... middle of paper ... ...s for both wheels appear to be similar for equivalent orientation and location. For both of the cast and forged wheels, Paris slope was higher for circumferential crack growth in the rim and radial crack growth in the web. Based on the tests made, higher levels of crack were exhibited in the cast material, particularly in the threshold regime.
Osteoporosis causes bones to become brittle and weak due to excessive amount of resorption. Something as mild as a cough or bending over to pick something up could cause a bone fracture. Most fractures caused by osteoporosis occur in the hip, wrist, or spine. On a molecular level, osteoclasts and osteoblasts balance the bone by acts or resorption and deposition. Osteoclasts are furnished with the ability to lower pH in their surroundings.
and ceramics (such as bio-inert alumina, toughened zirconia and bioactive calcium phosphate ceramics & bio-glass ceramics) are very common. But these materials are considerably heavier, denser & stiffer than normal human bone . The modulus mismatch between an artificial implant material and the host tissue can cause bone resorption at the bone-implant interface, which leads to implant instability and failure . A long term functioning bone replacement requires the establishment of a stable bone-implant interface, which necessitates the careful matching of the mechanical behavior as well as mechanical properties of synthetic implant materials with the natural tissue [7,
Fixed and semi-movable joints Not all joints are freely movable. After growth is complete, the bones of the skull become fixed together by fibrous tissue, forming immovable suture joints, in the lower leg, the tibia and fibula are stabilized by ligaments that allow only a small amount of movement. Types of synovial joint Ina synovial joint, the shape of articular cartilage surfaces and the way they fit together determine the range and direction of the joints movement. Hinge and pivort joints move only in one plane for example from side to side or up and down, while ellipsoidal joints are able to move in two planes at right angles to each other. most joints in the body can move in more than two planes, which allows for a wide range of movements.
Enamels appearance is semi translucent and the external color is a bluish white. The anatomical crown of the tooth is wrapped in enamel. Healthy teeth have crowns are a yellowish white due to the underlying dentine modifying the enamel so the bluish color only appears on unworn incisors and is seen only on the intact tooth edges. Enamel has so much strength it is recognized as the hardest tissue in the body but the properties of enamel differ depending on the locations with the tissue. For example, subsurface enamel is weaker than the harder surface enamel.
The Femur is stronger than concrete and its hollow! The skeleton has several functions like supporting the body, protection for vital organs, and the production of blood cells. For support the skeletal system uses a series of bones like the femur, fibula, tibia, and the vertebral column (figure 1). The skeleton has a few joint throughout the body, such as the hinge joint found at the patella and the elbow joint. Both of these joints are referred to as Ginglymus or hinge joint.