The human skeleton is a set of organized solid formations of bone tissue that make up the skeleton for other components of the human body. Thus, tendons are attached to the bones, connected to the muscles.
The human cranium and chest, the pelvic region and the abdominal cavity, formed by muscles and fascia (connective tissue membranes covering organs, vessels and nerves) attached to bones, serve as a container for internal organs. Also, dense bone tissue provides their mechanical protection from external influences, and muscle innervation leads to a change in the position of bones and joints like a lever, thereby moving the human body. Due to its rigidity and stability, the skeleton holds the entire mass of the human body and lifts it above the ground.
Skeleton structure
For the convenience of study, the skeleton is conditionally divided into 4 sections: the skeleton of the head (cranial box), the skeleton of the body, which includes the human chest and spine, as well as the skeleton of the free upper andlower limbs with belts. The girdle of the upper limb includes the shoulder blades and collarbones, and the girdle of the lower limb includes the bones of the pelvic joint.
The human spinal column, in turn, has 5 sections and 4 bends: the cervical, thoracic, lumbar, sacral and fused vertebrae of the coccyx. Due to these bends, the spine acquires the shape of the Latin "S", and thanks to this structure, a person is upright and maintains balance during movement.
Thoracic Anatomy
The human chest has the shape of a truncated pyramid and is a natural receptacle for the heart with large vessels, lungs with trachea and bronchi, thymus, esophagus and multiple lymph nodes. Its skeleton consists of 12 thoracic vertebrae, the sternum and 12 pairs of ribs enclosed between them. The differences between the thoracic vertebrae are small articular surfaces on the transverse processes, to which the costal heads are attached. The first - seventh pairs of ribs are fixed directly to the sternum, the eighth - tenth pairs of cartilaginous ends are attached to the cartilage of the overlying ribs, and the ends of the last two pairs remain free. The special structure of the human chest, namely the semi-movable joints of the ribs with the vertebrae and sternum, supported by cartilage and a complex ligamentous apparatus, allows it to expand when inhaling and reflexively narrow when exhaling, participating in respiratory movements. The thoracic cavity is an anatomical space located inside the chest and delimiteddiaphragm below. Just like the human chest, it has four walls, which are reinforced with muscles and fascia, which form the vagina for the latter. Also in the walls there are multiple natural openings for the passage of blood and lymphatic vessels and peripheral nerves. People with different builds have different shapes of the chest. Therefore, the physique is determined by the magnitude of the epigastric angle, the direction of the ribs and the distance between them.
