|
Synsacrum
The synsacrum is a skeletal structure of birds and other dinosaurs, pterosaurs, as well as xenarthran mammals, in which the sacrum is extended by incorporation of additional fused or partially fused caudal or lumbar In tetrapod anatomy, lumbar is an adjective that means of or pertaining to the abdominal segment of the torso, between the diaphragm (anatomy), diaphragm and the sacrum. Naming and location The lumbar region is sometimes referred to as the lowe ... vertebrae. Some posterior thoracic vertebrae, the lumbar, sacral and a few anterior caudal vertebrae are fused to form a complex bone called synsacrum. In birds, inate bones are fused with the synsacrum to a greater or lesser extent, according to species, forming an avian pelvis. This forms a more extensive rigid structure than the pelvis of a mammal, fulfilling requirements for flight, locomotion and respiration. Posterior to the bird synsacrum there are a few free caudal vertebrae, the last of which is the pygostyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird Skeleton
Bird anatomy, or the physiological structure of birds' bodies, shows many unique adaptations, mostly aiding flight. Birds have a light skeletal system and light but powerful musculature which, along with circulatory and respiratory systems capable of very high metabolic rates and oxygen supply, permit the bird to fly. The development of a beak has led to evolution of a specially adapted digestive system. Skeletal system Birds have many bones that are hollow ( pneumatized) with criss-crossing struts or trusses for structural strength. The number of hollow bones varies among species, though large gliding and soaring birds tend to have the most. Respiratory air sacs often form air pockets within the semi-hollow bones of the bird's skeleton. The bones of diving birds are often less hollow than those of non-diving species. Penguins, loons, puffins, and kiwis are without pneumatized bones entirely. Flightless birds, such as ostriches and emus, have pneumatized femurs and, in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur Anatomy
This glossary explains technical terms commonly employed in the description of dinosaur body fossils. Besides dinosaur-specific terms, it covers terms with wider usage, when these are of central importance in the study of dinosaurs or when their discussion in the context of dinosaurs is beneficial. The glossary does not cover ichnological and bone histological terms, nor does it cover measurements. A B C D E F G H I J L M N O P Q R S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacrum
The sacrum (: sacra or sacrums), in human anatomy, is a triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part of the pelvic cavity, between the two wings of the pelvis. It forms joints with four other bones. The two projections at the sides of the sacrum are called the alae (wings), and articulate with the ilium at the L-shaped sacroiliac joints. The upper part of the sacrum connects with the last lumbar vertebra (L5), and its lower part with the coccyx (tailbone) via the sacral and coccygeal cornua. The sacrum has three different surfaces which are shaped to accommodate surrounding pelvic structures. Overall, it is concave (curved upon itself). The base of the sacrum, the broadest and uppermost part, is tilted forward as the sacral promontory internally. The central part is curved outward toward the posterior, allowing greater room for the pelvic cavity. In a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycogen Body
A glycogen body is an oval structure in the spinal cord of birds that is made of specialized cells that contain large amounts of glycogen. Housed within the synsacrum, the function of this structure is not known, but it does not seem to be related to the normal function of glycogen in animals, which is the storage of energy. Glycogen bodies may also have been present in some non-avian dinosaurs and are possibly the explanation for the structure that was once thought to be a "second brain" in animals such as ''Stegosaurus ''Stegosaurus'' (; ) is a genus of herbivorous, four-legged, armored dinosaur from the Late Jurassic, characterized by the distinctive kite-shaped upright plates along their backs and spikes on their tails. Fossils of the genus have been fo ...''. References {{reflist Bird anatomy Dinosaur anatomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutionary history, evolution of dinosaurs is a subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya and their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, Evolution of birds, having evolved from earlier Theropoda, theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds. Dinosaurs are varied from taxonomy (biology), taxonomic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenarthra
Xenarthra (; from Ancient Greek ξένος, xénos, "foreign, alien" + ἄρθρον, árthron, "joint") is a superorder and major clade of placental mammals native to the Americas. There are 31 living species: the anteaters, tree sloths, and armadillos. Extinct xenarthrans include the glyptodonts, pampatheres and ground sloths. Xenarthrans originated in South America during the late Paleocene about 60 million years ago. They evolved and diversified extensively in South America during the continent's long period of isolation in the early to mid Cenozoic Era. They spread to the Antilles by the early Miocene and, starting about 3 million years ago, spread to Central and North America as part of the Great American Interchange. Nearly all of the formerly abundant megafaunal xenarthrans became extinct at the end of the Pleistocene. Characteristics Xenarthrans share several characteristics that are not present in other placental mammals, which suggest that xenarthrans desce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caudal Vertebrae
Caudal vertebrae are the vertebrae of the tail in many vertebrates. In birds, the last few caudal vertebrae fuse into the pygostyle, and in apes, including humans, the caudal vertebrae are fused into the coccyx. In many reptiles, some of the caudal vertebrae bear ribs, the caudal ribs, though these are often fused with the vertebrae. The caudal vertebrae often articulate with haemal arches ventrally. The number of caudal vertebrae in animals can vary greatly. Anguid lizards have been reported to have as many as 111 caudal vertebrae, whereas as few as seven are present in the tail of the early therapsid ''Tapinocaninus''. In lepidosaurs and captorhinids, the caudal vertebrae possess fracture planes at mid-length that allow caudal autotomy. In frogs, the few caudal vertebrae are fused together to form part of the urostyle. References Skeletal system Vertebrate anatomy {{vertebrate-anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lumbar Vertebrae
The lumbar vertebrae are located between the thoracic vertebrae and pelvis. They form the lower part of the back in humans, and the tail end of the back in quadrupeds. In humans, there are five lumbar vertebrae. The term is used to describe the anatomy of humans and quadrupeds, such as horses, pigs, or cattle. These bones are found in particular cuts of meat, including tenderloin or sirloin steak. Human anatomy In human anatomy, the five vertebrae are between the rib cage and the pelvis. They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse process (since it is only found in the cervical region) and by the absence of facets on the sides of the body (as found only in the thoracic region). They are designated L1 to L5, starting at the top. The lumbar vertebrae help support the weight of the body, and permit movement. General characteristics The adjacent figure depicts the general cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Innominate Bone
The hip bone (os coxae, innominate bone, pelvic bone or coxal bone) is a large flat bone, constricted in the center and expanded above and below. In some vertebrates (including humans before puberty) it is composed of three parts: the ilium, ischium, and the pubis. The two hip bones join at the pubic symphysis and together with the sacrum and coccyx (the pelvic part of the spine) comprise the skeletal component of the pelvis – the pelvic girdle which surrounds the pelvic cavity. They are connected to the sacrum, which is part of the axial skeleton, at the sacroiliac joint. Each hip bone is connected to the corresponding femur (thigh bone) (forming the primary connection between the bones of the lower limb and the axial skeleton) through the large ball and socket joint of the hip. Structure The hip bone is formed by three parts: the ilium, ischium, and pubis. At birth, these three components are separated by hyaline cartilage. They join each other in a Y-shaped portion of ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pygostyle
Pygostyle is a skeletal condition in which the final few caudal vertebrae are fused into a single ossification, supporting the tail feathers and musculature. In modern birds, the rectrices attach to these. The pygostyle is the main component of the uropygium, a structure colloquially known as the bishop's nose, parson's nose, pope's nose, or sultan's nose. This is the fleshy protuberance visible at the posterior end of a bird (most commonly a chicken or turkey) that has been dressed for cooking. It has a swollen appearance because it also contains the uropygial gland that produces preen oil. Evolution Pygostyles probably began to evolve very early in the Cretaceous period, perhaps 140 – 130 million years ago. The earliest known species to have evolved a pygostyle were members of the Confuciusornithidae. The structure provided an evolutionary advantage, as a completely mobile tail as found in species such as ''Archaeopteryx'' is detrimental to its use for flight control. Mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
