Bird flight

Wings of birds to fly movement serving organs, caused by alteration of the forelimbs. When flying with them is generated lift and propulsion.

Anatomy

Skeleton

The wings of birds are reformed forelimbs, so the wing skeleton is like the forelimbs of other land vertebrates from an upper arm bone (humerus ), the forearm bones ulna ( ulna ) and radius (radius ) as well as the hand bones. In adaptation to the changed function of flying these bones have greatly changed.

When wearing a wing of mostly vigorous trained humerus is placed horizontally. The ulna is stronger than the radius and serves as the insertion site of the secondaries. The ulna lies anterior to the radius, both bones are parallel to the humerus while wearing wings.

The greatest changes have experienced the hand bones.

• Whereas the development of even applied distal ( distal ) carpal bones (ossa carpals distalia ) fused to one another and to the other with the proximal ( proximal ) ends of the original three metacarpal bones ( metacarpals ), which thus only form a bone to Carpometacarpus. The Carpometacarpus forms a bone clasp. The thicker branch of this clip ( probably the second metacarpal bone ) is called the metacarpal majus, the thinner branch ( probably the third metacarpal bone ) as metacarpal minus.

The number of the fingers is reduced to three:

• The thumb ( Digitus alularis ) consists only of a finger bone of the phalanx digiti alulae.
• A larger finger Digitus major, consisting of two phalanges ( proximal phalanx and distal phalanx digiti ).
• A small finger Digitus minor, consists of a bone ( phalanx digiti minoris ).

The counted from the inside to the outside primaries 1-6 are attached to the Carpometacarpus, the primaries 7 to 10 at the two finger bones of Digitus major.

Wing membranes

Wing membranes brace the different wings pieces together, fill in the spaces between the bones and limit the wing core forwards and backwards. Most important are the front wing membrane, the rear wing membrane and the large Randligamend between elbows and metacarpal bones.

Spring

The flight feathers are the largest feathers on the wing and are divided according to insertion site in primaries and secondaries. A connective tissue band keeps it in the correct position. They grab each other like roof tiles. The two spring tabs are unevenly wide, so that the draft will cause the springs so turn the beat up that the air between the feathers can pass deleted. When the blade strikes again down, flip back and form a closed surface. The flight feathers are usually greatly reduced in flightless birds.

The flight feathers are covered at the bases of several rows of smaller blankets, so that a complete circuit of the wing is made.

The small springs supported by the thumb at the front edge of the blade are called Daumenfittich or Alula and used in high speed flight, and to control the brakes.

The folded wings are seen from above for the most part covered by the shield springs.

Muscles, tendons and ligaments

About 50 different muscles contribute to the movements of the wings. The two largest of which is called pectoral muscle and set the sternum crest ( crista sterni ) to. On the surface of the pectoralis major is ( pectoralis major or the pectoralis superficialis ). When it contracts, the wing is pulled down and rotated forward and downward. It is the largest muscle of the bird.

The little chest muscle ( pectoralis minor, pectoralis profundus muscle or supracoracoideus ) is far below the surface directly over the ribs and pulls the sternum comb through the three bones in hole ( foramen triosseum ) to the top of the upper arm bone ( humerus). The three bone hole is between three bones of the shoulder joint, between the coracoid ( coracoid ), the shoulder blade (scapula ) and the wishbone ( furcula ). If contracts of Small chest muscle, the wing is thereby raised.

The pectoralis minor is supported by the deltoid muscle ( deltoid ), which pulls the wings without a force redirection through the three bones in hole straight up and down at the same time reverses the rotation of the wing forward. In addition, the deltoid muscle spans the front wing membrane. The deltoid muscle is composed of two parts, the anterior deltoid and the posterior deltoid. In songbirds its main component is greatly reduced or absent.

On the wings themselves are still many smaller muscles that control the exact position of the sash. The Musculus rhomboideus pulls the wing forward, latissimus dorsi pulls the wings to the rear. Biceps brachii and triceps brachii pulling the wings forward and backward. Extensor carpi carpi and flexor stretch and flex the wrist. The finger extensor digiti be musculus flexor digiti and stretched and bent. More muscles move each finger.

Function

By means of springs a streamlined profile (see the wing ) is generated. While gliding ( no active wing beat ) is generated at the bottom of a slight pressure on the top and a strong vacuum that pulls the wings and so the bird upwards. A technical implementation of the bird's flight takes place in the ornithopter.

Gallery

A Mute Swan (Cygnus olor) spreads her wings.

Stripe -tailed Hummingbird ( Eupherusa eximia ) in Schwirrflug

Pied Kingfisher ( Ceryle rudis ) in Rüttelflug

Weißkehlmyiagra ( Myiagra inquieta ) in flight