Birds have long bones what can reduce the burden when flying

The long bones are hollow and filled with air.

It's like a tube, it's light.

The long bones of birds are hollow.

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The skeletal system of birds is light and strong, most of the bones are filled with air, and most of them are healed together, making them very strong. Their bones can be divided into several major parts such as the skull, vertebrae, sternum, and limb bones. The skull is thin and light, mainly composed of the braincap, facial and frontal bones, with a honeycomb porous tissue, most of the head bones are healed together and become a whole, and only two occipital condyles are connected to the cervical vertebrae in the occipital region, so the head rotates flexibly.

The upper and lower mandibles protrude to form a beak, the cranial cavity is enlarged, the top of the skull is rounded, and the orbit is enlarged. The spine is composed of five parts: cervical, thoracic, lumbar, recommendary, and caudal vertebrae. The cervical vertebrae are usually l3-16, and the articular surfaces between the vertebrae are saddle-shaped, and this special joint makes the movement between the vertebrae very flexible.

The six thoracic vertebrae are connected to the ribs and sternum to form the thoracic cage, and the posterior edge of the sternum has two deep notches on each side of the keel. The last thoracic, lumbar, and part of the caudal vertebra heal into the donor bone and heal with the broad pelvics (iliacium, ischium, and pubis) to form a solid scaffold that supports the bird's body weight as it walks on the ground, the coccyx degenerates, and the last few caudal vertebrae heal into the coccygeal bone to support the fan-shaped tail feathers.

The shoulder girdle is composed of the scapula, the black coracoid and the clavicle, the left and right clavicles heal into a V-shape at the midline of the abdomen, called the wishbones, the wing bones are composed of the humerus, ulna, radius, carpal bones, metacarpal bones, phalanges, etc., and the forelimbs are specialized into wings, in which the carpal bones and metacarpal bones are partially healed, and some phalanges are degenerated and disappear. Flight feathers born on the ulna are called secondary flight feathers, and those born on the carpal bones, metacarpal bones and phalanges are called primary flight feathers.

The girdle is healed from the iliac bone, ischial bone and pubic bone into a thin and complete skeleton, and heals with the healing bone, giving strong support to the hind limbs, and the left and right ischiale and pubic bones are stretched together to the side and back to form an open pelvic, the male pubic bone is short and tight, and the female bird is slightly longer and wider, which is conducive to laying hard shell eggs. The hind limbs are strong, the femur and girdle form joints, the fibula degenerates into a spine, the tibia and part of the tarsal bone form a tibial tarsus, the tarsal bone and a part of the metatarsal bone form a tarsal metatarsal, four phalanges, three toes forward, one toe backward.

Almost all of the above is in the service of flying.

Birds are adapted to flight life and have significant specialization in the skeletal system, which is manifested as light and strong bones with gas-filled cavities in the bones. The skull, spine, pelvis, and limb bones heal. The limb bones and girdle bones are more deformed, the skull is thin, light and healed, and the occipital condyle is single.

The spine is divided into five parts: cervical, thoracic, lumbar, recommendary, and caudal vertebrae. The cervical vertebra is a heteroconcave vertebrae, the first one is called the atlas vertebrae, and the second one is called the pivotal vertebrae. The thoracic vertebrae are 5 to 6, and the bony ribs and sternum combine to form the thoracic cage.

Flying birds have well-developed sternum with keel protrusions, and a few thoracic vertebrae, lumbar vertebrae, recommended vertebrae and part of the caudal vertebrae are healed. The bone is a structure unique to birds. Open pelvis.

The bones are mostly hollow, thin and light, which is good for reducing weight when flying.

The bones of birds are very thin, some are healed together, the longer bones are hollow, and the rectum is very short, and the feces quickly enter the cloaca and are excreted, which helps to reduce weight and facilitate the careful movement of the fingers; The well-developed sternum of Tuanjing facilitates the attachment of the pectoral muscles to help flight, but it does not mean weight loss, so the developed sternum has nothing to do with weight loss when flying birds

a. The body forms a streamlined shape, which can reduce the resistance of the air and adapt to the air flight a.

b. Long bones are hollow, which can reduce weight and adapt to air flight b Error;

c. The rectum is short, does not store feces, and can lose weight Silver Attendant adapts to air flight Lack of beats c error;

d. The body temperature is constant d

Therefore, d