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 posture, protecting organs and tissues - these 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 internal organs and body systems. The skeleton also provides support, and through it the body moves in space and its position is determined. The motor function is performed using the combined coordinated actions of the bones, joints, muscles and nerve endings. The supporting function lies in the fact that the bones of the skeleton serve as the basis for the attachment of soft tissues and organs, which allows them to remain in their places all the time 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 chest, the brain is hidden in a strong skull. The blood-forming function is also inherent in the skeleton - in the bones of the skeleton there is a
red bone marrow, which takes part in 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. Inorganic compounds in the skeleton bones account for about 70%. With age, this figure increases, which leads to an increase in the fragility of bones and a decrease in their strength. For this reason, at a more advanced age, bone fusion will take longer.
Bone structure
Any bone of the human body consists of bone plates, beams and beams. The only difference is how compact these elements are. On a section of a tubular bone it is visible that outside the bone substance is dense, and inside is more friable. In the spongy substance, the crossbars are arranged so that they form cells between themselves. If the bone elements are densely arranged to 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 outside and makes the bone strong, while spongy, due to its structure, reduces bone mass. Their ratio can be different and depends on the function, shape and location in the body.
Periosteum
Outside, the bones are covered with periosteum. An exception is the surface of the joints, which are covered with hyaline cartilage. The periosteum is represented by dense connective tissue, which is fused to 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 the lower extremities
The musculoskeletal appart 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 departments, interconnected. One of them is motionless and serves as the basis for fastening 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 feature is a fixed arrangement of bones. The second - bones 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 for some, rotation.
The skeleton of the lower extremities of a person is adapted to perform the following functions: supporting, motor and spring. Thanks to the coordinated work of the joints, ligaments and muscle joints, the body movements are amortized 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 tibia
bones are represented by the tibial and fibular.
The thigh bone is the most massive and strongest in the human body, with the upper part connected to the pelvic bone and forms the hip joint. The ligaments of the hip joint are the most durable. Since they are focused on the main load to maintain the integrity of the joint.
Knee
The lower part of the femur is attached to the tibia, forming a knee joint, which is covered by the patella. The knee joint is capable of flexion, extension and rotation. Its 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 phalanx of the fingers. It increases the footprint and provides cushioning of the body.
The muscles connecting the skeleton of the lower extremities of the person are the most massive and strong in the body, due to the fact that they have the greatest load associated with the retention and movement of the entire human body.
At the junction of the bones of the lower extremities, thick cartilage pads are located that provide upright body and cushioning when jumping and running. They consist of elastic connective tissue that can contract under the action of loads and take its initial state. Any cartilage tissue has a high rate of regeneration, that is, restoration, in case of damage or abrasion.
Foot structure
The skeleton of the tarsus is represented by 7 bones, which are located in two rows between the lower leg and metatarsal. The calcaneus is located a little back and performs a supporting function. The metatarsus is represented by 5 tubular bones, which are connected to the phalanges of the fingers through joints. The skeleton of the toes consists of phalanges: the first finger is represented by two phalanges, the rest by three.
The foot is characterized by flexion, extension, abduction and turns. The movement of all bones is carried out by the muscles of the lower leg and foot. This determines a large number of options in determining the human body in space.
The foot, constantly in contact with the shoe, can be modified. 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 feet in different people are different. It depends on the proportions of the body, its mass and lifestyle. With the wrong selection of shoes, flat feet can develop - a decrease in the arch of the foot, which also causes certain inconvenience.
Thus, it is seen that the skeleton of the lower extremities of a person performs a very important function in the body. It determines the pose of the human body when walking, while reducing the load on the overlying organs and systems, thereby extending their lifespan. The musculoskeletal system of a person through itself combines all organs and systems into a single whole. The structure of the skeleton of the lower extremities of a person is fully consistent with the functions performed.