Musculoskeletal system of birds

Birds are animals that not only move on the ground, but also rise into the air, soar in the sky. Therefore, as a result of evolutionary development, a change in the mass and shape of their bodies was observed. At the same time there was accumulation of fat - energy reserve, decreased friction during movement, muscle mass was increased. At the same time, their skeleton and muscles changed, i.e. Musculoskeletal system of birds.
In many respects it is the same as in mammals. The musculoskeletal system of birds consists of an axial skeleton, a skull, a humerus and forearm, a scapula, thoracic vertebrae, pelvic and femur bones, etc.
At the same time, it is completely different than the musculoskeletal system of mammals. For example, the head of birds is small, because All the bones of the brain skull have fused, and the number of them has decreased. The skull is greatly relieved due to the fact that the bones are mostly hollow, and there is a toothless beak, which is covered only by the horn cover. Birds do not have bends of the spine, as in humans. The breast "human" cell is expanded, and in animals and birds it is compressed laterally.
The cervical section of the skeleton of birds is represented by 11-25 free vertebrae, but the thoracic vertebrae are firmly fastened together and in conjunction with the vertebrae of the lumbar region. The sacral section merged with the hindquarters of the hind limbs, and the sacrum was formed.
There is a difference in the facial skeleton, in the limb belt, and in the limbs themselves. For example, only birds have a keel - a cartilaginous outgrowth, which was formed when the collarbone is intergrown with the sternum. In flying birds, the sternum is developed quite strongly, and the keel is large.
The musculoskeletal system of birds includes the hind legs, which are two large, powerful pelvic bones, fused with a complex sacrum. And since the bird walks on two legs, the sacrum itself is also powerful. The sacrum is formed by fused sacral, lumbar, caudal vertebrae, therefore it is believed that there is no lumbar region in birds.
The skeleton of a bird differs from the skeletons of other living beings in that it is durable and light. This is achieved, firstly, because the bones of the birds are tubular. Secondly, the ease is explained by the cavity of the bones. Therefore, the mass of the skeleton of the bird is somewhere around 5-15% of the mass of its body. With the exception of the cervical spine, the entire spine is immovable.
Since the forelimbs have evolved into wings as a result of evolutionary development, the brush is almost not developed. But in birds that fly well, large pectoral muscles make up somewhere 15-20% of the mass, and their special arrangement contributes to the stability of birds in the air.

Below the level of development, than birds and mammals, is a class of reptiles. The body of such a reptile consists of a head, neck, trunk and limbs, except snakes and legless lizards, which are devoid of limbs. The structure of the locomotor system of reptiles is close to amphibians, but unlike them, it has a more ossified skeleton. A more progressive structure of the skeleton and musculature of such animals determined their mobility. The skeleton of reptiles, like the locomotor system of birds, also consists of their cervical, thoracic, sacral and caudal divisions. Long ribs are connected to the sternum, and a thorax is formed.
Reptiles, unlike other animals, have more dissected muscles, in particular, intercostal muscles. They can regulate the volume of the chest, compress and expand it, thereby making the process of breathing. Since the ribs of the reptiles end freely, this allows them to swallow a fairly large meal. They have a well developed tail section.
Summarizing, it can be noted that the skeletons of all animals have distinctive features, but they perform similar functions. They serve as a support for the body, protect the internal organs and help to move all living things in space.