The human musculoskeletal system is a complex system that works continuously from birth to the last day of life, performing a number of vital functions. Maintaining a constant body shape, walking upright, protecting organs and tissues are its main functions. Interacting with other departments and organs of the human body, they create and maintain its integrity and help to adapt to various conditions of life.
The entire musculoskeletal system of the human body is represented by two departments: passive (skeleton and its parts) and active (muscular system).
The skeleton is a collection of all the bones of the body, which are interconnected through joints and ligaments.
It forms a kind of framework that performs a protective function for the internal organs and systems of the body. The skeleton also provides support, and through it the organism is moved in space and its position is determined. Motor function is carried out with the help ofthe combined coordinated actions of bones, joints, muscles and nerve endings. The supporting function lies in the fact that the bones of the skeleton serve as the basis for attaching soft tissues and organs, which allows them to stay in their places all the time and not fall off. The protective function is provided by the presence of cavities in which the vital organs of the human body are located. So, the heart and lungs are closed by the chest, the brain is hidden in a strong cranium. The skeleton also has a blood-forming function - the bones of the skeleton contain red bone marrow, which takes part in hematopoiesis.
Composition of bone
The skeleton of any person consists of more than 200 bones. They are formed by bone tissues, which are represented by a large number of mineral and organic compounds. Minerals give bones hardness and strength, while organic substances are responsible for flexibility and elasticity. The share of inorganic compounds in the composition of the bones of the skeleton accounts for about 70%. With age, this figure increases, which leads to an increase in bone fragility and a decrease in their strength. For this reason, it will take more time for bones to heal in later life.
Structure of bone
Any bone of the human body consists of bone plates, beams and beams. The only difference is how compactly these elements are located. On a section of a tubular bone, it can be seen that the bone substance is dense on the outside, and looser on the inside. In the spongy substance, the crossbars are arranged so that they form cells between them. If the bones are tightly packedto each other in the form of concentric circles, then cavities are formed inside, in which the vessels and nerves are located. The compact substance is localized on the outside and makes the bone strong, while the spongy substance, due to its structure, reduces the mass of the bone. Their ratio can be different and depends on the function performed, form and location in the body.
Periosteum
Outside, the bones are covered with periosteum. An exception is the surfaces of the joints, which are covered with hyaline cartilage. The periosteum is represented by dense connective tissue, which is fused with the body of the bone. It contains a large number of blood vessels that carry nutrients to the bone, as well as osteoblasts involved in the formation of new bone cells. Therefore, the periosteum contributes to the growth of bones in thickness and their fusion in fractures.
Anatomy. Lower limb skeleton
The musculoskeletal apparatus has a very complex structure. All its features are directly related to the functions performed. The skeleton of the lower extremities of a person consists of two sections, interconnected. One of them is motionless and serves as the basis for attaching the bones of the second. The first is represented by the pelvic girdle and its bones - the skeleton of the girdle of the lower extremities. Its peculiarity is the fixed arrangement of bones. The second - the bones that are directly involved in the movement of the body - the skeleton of the free lower limb. The bones included in its composition are characterized by the possibility of changing position in various planes, and forsome and rotation.
The skeleton of the human lower extremities is adapted to perform the following functions: supporting, motor and spring. Thanks to the coordinated work of the joints, ligaments and muscle connections, the body movements are cushioned when walking, running or jumping. This allows you to reduce the load on the overlying parts of the body and organs.
Hip joint
The skeleton of the lower extremities, located below the pelvic bones, is represented by the femur, lower leg and foot. The bones of the lower leg are represented by the tibia and fibula. The femur bone is the most massive and strong in the human body; its upper part is connected to the pelvic bone and forms the hip joint. The ligaments of the hip joint are the strongest. Since the main burden of maintaining the integrity of the joint is concentrated on them.
Knee
The lower part of the femur is attached to the tibia, forming the knee joint, which is covered by the patella. The knee joint is capable of flexion, extension and rotation. His ligaments are located crosswise.
Ankle joint
The tibia, connecting with the talus, forms the ankle joint. The foot consists of the bones of the tarsus, metatarsus and phalanges of the fingers. It increases the footprint and provides cushioning to the body.
The muscles that connect the skeleton of the human lower limbs are the most massive and strong in the body, due to the fact that theybears the greatest burden associated with holding and moving the entire human body.
There are thick cartilaginous pads at the junctions of the bones of the lower extremities, which provide uprightness of the body and cushioning when jumping and running. They consist of elastic connective tissue that can compress under the action of loads and return to its initial state. Any cartilage tissue has a high rate of regeneration, that is, restoration, in case of damage or abrasion.
Structure of the foot
The tarsal skeleton is represented by 7 bones, which are located in two rows between the lower leg and metatarsus. The calcaneus is slightly located back and performs a supporting function. The metatarsus is represented by 5 tubular bones, which are connected to the phalanges of the fingers through the joints. The skeleton of the toes consists of phalanges: the first toe is represented by two phalanges, the rest by three.
The foot is characterized by flexion, extension, abduction and rotation. The movement of all bones is carried out by the muscles of the lower leg and foot. This determines a large number of options when determining the human body in space.
The foot, constantly in contact with the shoe, can change. Calluses, corns or growths appear on it, which leads to painful sensations. This is due to the fact that the shape and structure of the foot varies from person to person. It depends on the proportions of the body, its mass and lifestyle of a person. With the wrong choice of shoes,develop flat feet - a decrease in the arch of the foot, which also causes certain inconveniences.
Thus, it is clear that the skeleton of the lower extremities of a person performs a very important function in the body. It determines the posture of the human body when walking, while reducing the load on the overlying organs and systems, thereby prolonging their service life. The human musculoskeletal system through itself unites all organs and systems into a single whole. The structure of the skeleton of the human lower extremities is fully consistent with the functions performed.
