Bone is the hardest after tooth enamelsubstance, present in the human body and consisting of a special type of connective tissue. Its characteristic features include the presence of a solid, impregnated with mineral salts, fibrous intercellular substance and star cells, equipped with numerous processes. Classification and structure of bones allow us to understand how important the role of the musculoskeletal system in the body.
Classification of bones
Each bone is an independent organ consisting offrom two parts. The outer part is the periosteum, and the inner part is formed by a special connective tissue. Their cavities are the site of the most important human hematopoietic organ.
Classification of bones in form provides for the presence of the following groups:
- long or tubular;
- Short, which is otherwise called spongy;
- flat or wide;
- mixed, sometimes called abnormal;
Of the tubular is the skeleton of the extremities, inwhich they are called to perform the functions of leverage. Further classification of bones of this type provides for their separation into long and short ones. The first include the shoulder, thigh, forearm and shin. To the second - metacarpal, metatarsal, phalanges of fingers.
In short (spongy) bones, the shape resemblesan irregular cube or polyhedron. They are located in those places of the skeleton, where a combination of strength and mobility in the junctions is necessary. It's about wrists, tarsus.
Participation in the formation of body cavities and performanceprotective function is the prerogative of flat (broad) bones, which include the sternum, ribs, pelvis and cranial vault. The muscles are attached to their surfaces, and inside them, as in the case with the tubular, is the bone marrow.
Short bones in the human wrist allow using a brush to perform a variety of manipulations. And in the toes, the feet increase stability when the person is standing.
At airborne in the body there is a cavity lined with a mucous membrane and filled with air. Part of the bones of the skull refers to this species. For example, the frontal, latticed, upper jaw, wedge-shaped.
Classification of joints of bones
The whole set of bones forms a passive partthe musculoskeletal system functioning as a system, in many respects, in view of the availability of various types of connection, which ensures a different degree of mobility.
The joints of the bones are continuous and discontinuous. Also distinguish an intermediate type of compound, which is called symphysis.
Classification of human bones is important in medicineto prevent damage to the musculoskeletal system. Along with this, the type of tissues to be bonded is also important. This feature makes it possible to isolate among continuous joints fibrotic, bone and cartilaginous joints (synchondroses). Fibrous has a high level of strength and low mobility. Within this group of compounds, syndesmoses, seams and piercing are isolated. Syndemoses include ligaments and interosseous membranes.
Types of fibrous joints
Bundles in structure are thick beams orplates formed by a dense fibrous connective tissue and a significant amount of collagen fibers. Bundle, as a rule, provides the connection of two bones and reinforcement of the joint, limiting their movement. Capable of withstanding heavy loads.
With the help of the intercostal membranes are connecteddiaphysis of tubular bones, and also they are places of attachment of muscles. The interosseous membranes have holes through which blood vessels and nerves are carried.
One of the varieties of fibrous joints isseams of the skull, dividing according to the configuration of the joined edges into spongy, scaly and flat. All types of joints have a interlayer layer of connective tissue.
Vkolachivanie is also a special kindfibrous joint, observed at the junction of the tooth and bone tissue of the dental alveoli. The tooth and bone wall do not touch. They are separated by a thin plate consisting of connective tissue. It is called periodontium.
Synchondroses and synostoses
Classification of bone connections providesthe presence of synchondroses, in which fastening is carried out with the help of cartilaginous tissue. The main characteristics of synchondrosis are elasticity, strength.
When the cartilaginous interlayer is replaced between the bones by a bone tissue, they lead to a synostosis. Mobility in this case goes to zero, and strength indicators increase.
The most mobile type of joint are the joints. The characteristic features of these discontinuous fastenings are the presence of special components: articular surfaces, articular cavity, synovial fluid and capsule.
The articular surface covers the hyaline cartilage,and the cavity is a slit-like space between the articular surfaces of bones surrounded by an articular capsule and containing a significant amount of synovial fluid.
Fractures of bones
A fracture is a complete or partial violation of the integrity of the bone, which has arisen from an external trauma or in the process of changing the tissue that caused the disease.
The full name of the fracture can be applied whentaking into account a number of signs, which are primarily a kind of damaged, in which the broken bone is localized. In addition, the name of the fracture includes the nature of the causes of its occurrence (traumatic or pathological).
Classification of bone fractures in the first placeprovides for their division into congenital and acquired. The presence of congenital fractures is caused by disturbances in intrauterine development and is rare. Among them, the most likely ones are those in which the skull, ribs, collarbone, shoulders and hip suffer. Fractures that have arisen as a result of birth trauma, have no relationship to fetal development, therefore, they are of acquired character.
Acquired fractures can be traumaticand pathological. The former are the consequence of mechanical action and are localized either at the site of this exposure (direct) or outside this zone (indirect). Another group of fractures includes those that are formed due to a lesion of bone tissue by a tumor or other inflammatory or dystrophic processes.
Open and closed fractures
Open fractures are characterized by damageskin and mucous membranes in places of traumatic impact, which led to a violation of their integrity. If there is a wound and tissues are crushed, this provokes a risk of infection and the subsequent development of post-traumatic osteomyelitis.
With closed fracture, the integrity of the skin is not disturbed.