Skeleton of the lower limbs of man: structure and functions

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, 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 in various conditions of life.

The entire musculoskeletal system of the human body is represented by two divisions: passive (the skeleton and its parts) and the active (muscular system).

The skeleton is the totality of all the bones of the body, which are joined together by joints and ligaments. It forms a kind of skeleton, which performs a protective function for the internal organs and systems of the body. Also, the skeleton provides support, and by means of it the organism is moved in space and its position is determined. The motor function is performed by means of the combined coordinated actions of bones, joints, muscles and nerve endings. The basic function is that the bones of the skeleton serve as the basis for attaching soft tissues and organs, which allows them to stay in their places at all times and not to subside. 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 thorax, the brain is hidden in a solid cranium. Also, the skeleton is inherent in the blood-forming function - in the bones of the skeleton is located the red bone marrow, which takes part in the hematopoiesis.

Bone composition

The skeleton of any person consists of more than 200 bones. They are formed by bone tissue, which is 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 proportion of inorganic compounds in the bones of the skeleton accounts for about 70%. With age, this figure increases, which leads to an increase in the fragility of bones and reduce their strength. For this reason, at a more mature age, bone fusion will take more time.

Structure of the bone

Any bone of the human body consists of bone plates, beams and beams. The only difference is how compact these elements are located. On a section of the tubular bone, it can be seen that the bone substance is dense outside, and the inside is more friable. In the spongy substance, the bars are arranged so that they form cells. If the bone elements are densely located to each other in the form of concentric circles, then inside cavities are formed in which the vessels and nerves are located. The compact substance is localized outside and makes the bone strong, while the spongy substance, due to its structure, reduces the bone mass. The ratio of them can be different and depends on the performed function, shape and location in the body.

Periosteum

Outside, the bones are covered with the periosteum. Exception is the surface of the joints, which are covered with hyaline cartilage. The pimple is represented by a dense connective tissue, which is fused with the body of the bone. It contains a large number of blood vessels carrying nutrients to the bone, as well as osteoblasts involved in the formation of new bone cells. Therefore, the periosteum promotes the growth of bones in thickness and their fusion in fractures.

Anatomy. Skeleton of lower extremities

The musculoskeletal appartement has a very complex structure. All its features are directly related to the functions performed. The skeleton of the lower limbs of a man consists of two sections interconnected. One of them is fixed and serves as the basis for fixing the bones of the second one. The first is represented by the pelvic girdle and its bones - the skeleton of the lower extremity belt. Its special feature is the fixed location of bones. The second - the bones directly involved in the movement of the body - the skeleton of a free lower limb. For the bones that make up its composition, it is typical to change the position in different planes, and for some, rotation.

The skeleton of the lower limbs of a person is adapted to perform the following functions: supporting, motor and spring. Thanks to the well-coordinated work of the joints, ligaments and muscular connections, the movement of the body during walking, running or jumping is amortized. This allows you to reduce the burden 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, shank and foot. The bones of the lower leg are tibial and fibular.
The hip bone is the most massive and strong in the human body, the upper part is connected to the pelvic bone and forms the hip joint. Bundles of the hip joint are the strongest. Since they are concentrated on the main load to maintain the integrity of the joint.

Knee

At the bottom, the femur is attached to the tibia, forming the joint of the knee, which is covered with the patella. The knee joint is capable of flexion, extension and rotation. Its bunches are cross-shaped.

Ankle joint

The tibia, connecting with the talus, forms an ankle joint. The foot consists of tarsal bones, metatarsus and phalanges of fingers. It increases the footprint and provides shock absorption to the body.

The muscles that connect the skeleton of the lower limbs of a person are the most massive and strong in the body, because they have the greatest burden associated with the retention and movement of the entire human body.

In the junction of the bones of the lower limbs are located thick cartilaginous pads, which provide a straightforward body and cushioning for jumping and running. They consist of an elastic connective tissue that can compress under the action of loads and take its initial state. Any cartilaginous tissue has a high rate of regeneration, that is, restoration, in case of damage or erasure.

Structure of the foot

The skeleton of the tarsus is represented by 7 bones that are arranged in two rows between the shin and the plus. The calcaneus is slightly located back and performs a supporting function. The metatarsus is represented by 5 tubular bones that are connected to the phalanx of the fingers through the joints. The skeleton of the toes consists of phalanges: the first finger is represented by two phalanges, the rest is three.

The foot is characterized by flexion, extension, retraction and turns. 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.

Stop, constantly in contact with shoes, can be modified. Corns, pods 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. With improper shoe selection, flat feet can develop - a decrease in the arch of the foot, which also causes certain inconveniences.

Thus, it is evident that the skeleton of the lower limbs of a person performs a very important function in the body. It determines the position of the human body when walking, while reducing the load on the overlying organs and systems, thereby prolonging the life of the body. The musculoskeletal system of man by means of himself unites all organs and systems into a single whole. The structure of the skeleton of the lower limbs of man fully corresponds to the functions performed.