tailieunhanh - Figure Drawing - Bird Horns

Bird characteristics: Body always covered with feathers; feet (toes and usually tarsometatarsus) covered with scales (thickened skin). Aquatic birds have webbed toes. No teeth; horny beak. Lightweight skeleton in flying birds (many hollow bones), with keel on sternum for attachment of flight muscles (pectoral muscles). No keel in large flightless birds (ostrich, emu, rhea). Completely bony ribs (no rib cartilage). Clavicles fused into single bone, the furculum (wishbone). Numerous neck vertebrae (number varies by species) provide great neck flexibility. Some of the middle thoracic vertebrae fused in some species (chicken); posterior thoracic, all lumbar, and all sacral vertebrae fused into. | 218 BIRD ANATOMY CHICKEN SKELETON Gallus gallus STERNUM PATELLA SYNSACRUM TAIL VERTEBRAE - CARPOMETACARPUS PHALANGES CORACOID ATLAS LOWER JAW FIRST METATARSAL ALL CHICKEN DRAWINGS FROM SPECIMENS FIRST TOE PHALANGES KEEL OF STERNUM FIBULA TIBIOTARSUS TARSOMETATARSUS SECOND TOE THIRD TOE FOURTH TOE SECOND FINGER THIRD FINGER ULNAR CARPAL THORACIC VERTEBRAE FUSED SCAPULA RIB ILIUM PYGOSTYLE ISCHIUM Bird characteristics Body always covered with feathers feet toes and usually tarsometatarsus covered with scales thickened skin . Aquatic birds have webbed toes. No teeth horny beak. Lightweight skeleton in flying birds many hollow bones with keel on sternum for attachment of flight muscles pectoral muscles . No keel in large flightless birds ostrich emu rhea . Completely bony ribs no rib cartilage . Clavicles fused into single bone the furculum wishbone . Numerous neck vertebrae number varies by species provide great neck flexibility. Some of the middle thoracic vertebrae fused in some species chicken posterior thoracic all lumbar and all sacral vertebrae fused into synsacrum which in turn is fused to the pelvis. Short flexible tail terminates in stout bone pygostyle for support of highly mobile long tail feathers. Wing arm skeleton modified for flying ostrich and penguins evolved from flying ancestors . Wrist joint automatically straightens when elbow joint is straightened conversely wrist joint automatically bends when elbow joint is bent. Individual hand and finger bones reduced in number and largely fused together for support of primaries outer flight feathers . Three digits present small third digit nonmovable. Short alular feathers attach to movable first digit. Secondaries inner flight feathers attach to rear edge of ulna. Three toes point forward and one points backward in most species . chicken hawk crow or two toes forward and two back . woodpecker parrot . Ostrich has two toes per foot. Toes terminate with claws. Male chicken has bony spur covered with .