Reptiles are tetrapod animals in the class Reptilia, comprising today's turtles, snakes, lizards and their extinct relatives. The study of these traditional reptile orders combined with that of modern amphibians, is called herpetology; because some reptiles are more related to birds than they are to other reptiles, the traditional groups of "reptiles" listed above do not together constitute a monophyletic grouping or clade. For this reason, many modern scientists prefer to consider the birds part of Reptilia as well, thereby making Reptilia a monophyletic class, including all living Diapsids; the earliest known proto-reptiles originated around 312 million years ago during the Carboniferous period, having evolved from advanced reptiliomorph tetrapods that became adapted to life on dry land. Some early examples include Casineria. In addition to the living reptiles, there are many diverse groups that are now extinct, in some cases due to mass extinction events. In particular, the Cretaceous–Paleogene extinction event wiped out the pterosaurs, plesiosaurs and sauropods, as well as many species of theropods, including troodontids, dromaeosaurids and abelisaurids, along with many Crocodyliformes, squamates.
Modern non-avian reptiles inhabit all the continents except Antarctica, although some birds are found on the periphery of Antarctica. Several living subgroups are recognized: Testudines, 350 species. Reptiles are tetrapod vertebrates, creatures that either have four limbs or, like snakes, are descended from four-limbed ancestors. Unlike amphibians, reptiles do not have an aquatic larval stage. Most reptiles are oviparous, although several species of squamates are viviparous, as were some extinct aquatic clades – the fetus develops within the mother, contained in a placenta rather than an eggshell; as amniotes, reptile eggs are surrounded by membranes for protection and transport, which adapt them to reproduction on dry land. Many of the viviparous species feed their fetuses through various forms of placenta analogous to those of mammals, with some providing initial care for their hatchlings. Extant reptiles range in size from a tiny gecko, Sphaerodactylus ariasae, which can grow up to 17 mm to the saltwater crocodile, Crocodylus porosus, which can reach 6 m in length and weigh over 1,000 kg.
In the 13th century the category of reptile was recognized in Europe as consisting of a miscellany of egg-laying creatures, including "snakes, various fantastic monsters, assorted amphibians, worms", as recorded by Vincent of Beauvais in his Mirror of Nature. In the 18th century, the reptiles were, from the outset of classification, grouped with the amphibians. Linnaeus, working from species-poor Sweden, where the common adder and grass snake are found hunting in water, included all reptiles and amphibians in class "III – Amphibia" in his Systema Naturæ; the terms "reptile" and "amphibian" were interchangeable, "reptile" being preferred by the French. Josephus Nicolaus Laurenti was the first to formally use the term "Reptilia" for an expanded selection of reptiles and amphibians similar to that of Linnaeus. Today, the two groups are still treated under the same heading as herptiles, it was not until the beginning of the 19th century that it became clear that reptiles and amphibians are, in fact, quite different animals, Pierre André Latreille erected the class Batracia for the latter, dividing the tetrapods into the four familiar classes of reptiles, amphibians and mammals.
The British anatomist Thomas Henry Huxley made Latreille's definition popular and, together with Richard Owen, expanded Reptilia to include the various fossil "antediluvian monsters", including dinosaurs and the mammal-like Dicynodon he helped describe. This was not the only possible classification scheme: In the Hunterian lectures delivered at the Royal College of Surgeons in 1863, Huxley grouped the vertebrates into mammals and ichthyoids, he subsequently proposed the names of Ichthyopsida for the latter two groups. In 1866, Haeckel demonstrated that vertebrates could be divided based on their reproductive strategies, that reptiles and mammals were united by the amniotic egg; the terms "Sauropsida" and "Theropsida" were used again in 1916 by E. S. Goodrich to distinguish between lizards and their relatives on the one hand and mammals and their extinct relatives on the other. Goodrich supported this division by the nature of the hearts and blood vessels in each group, other features, such as the structure of the forebrain.
According to Goodrich, both lineages evolved from an earlier stem group, Protosauria in which he included some animals today considered reptile-like amphibians, as well as early reptiles. In 1956, D. M. S. Watson observed that the first two groups diverged early in reptilian history, so he divided Goodrich's Protosauria between them, he reinterpreted Sauropsida and Theropsida to exclude birds and mammals, respectively. Thus his Sauropsida included Procolophonia, Millerosauria, Squamata, Rhynchocephalia
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago, although the exact origin and timing of the evolution of dinosaurs is the subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201 million years ago. Reverse genetic engineering and the fossil record both demonstrate that birds are modern feathered dinosaurs, having evolved from earlier theropods during the late Jurassic Period; as such, birds were the only dinosaur lineage to survive the Cretaceous–Paleogene extinction event 66 million years ago. Dinosaurs can therefore be divided into birds; this article deals with non-avian dinosaurs. Dinosaurs are a varied group of animals from taxonomic and ecological standpoints. Birds, at over 10,000 living species, are the most diverse group of vertebrates besides perciform fish. Using fossil evidence, paleontologists have identified over 500 distinct genera and more than 1,000 different species of non-avian dinosaurs.
Dinosaurs are represented on every continent by fossil remains. Through the first half of the 20th century, before birds were recognized to be dinosaurs, most of the scientific community believed dinosaurs to have been sluggish and cold-blooded. Most research conducted since the 1970s, has indicated that all dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction; some were herbivorous, others carnivorous. Evidence suggests that egg-laying and nest-building are additional traits shared by all dinosaurs and non-avian alike. While dinosaurs were ancestrally bipedal, many extinct groups included quadrupedal species, some were able to shift between these stances. Elaborate display structures such as horns or crests are common to all dinosaur groups, some extinct groups developed skeletal modifications such as bony armor and spines. While the dinosaurs' modern-day surviving avian lineage are small due to the constraints of flight, many prehistoric dinosaurs were large-bodied—the largest sauropod dinosaurs are estimated to have reached lengths of 39.7 meters and heights of 18 meters and were the largest land animals of all time.
Still, the idea that non-avian dinosaurs were uniformly gigantic is a misconception based in part on preservation bias, as large, sturdy bones are more to last until they are fossilized. Many dinosaurs were quite small: Xixianykus, for example, was only about 50 cm long. Since the first dinosaur fossils were recognized in the early 19th century, mounted fossil dinosaur skeletons have been major attractions at museums around the world, dinosaurs have become an enduring part of world culture; the large sizes of some dinosaur groups, as well as their monstrous and fantastic nature, have ensured dinosaurs' regular appearance in best-selling books and films, such as Jurassic Park. Persistent public enthusiasm for the animals has resulted in significant funding for dinosaur science, new discoveries are covered by the media; the taxon'Dinosauria' was formally named in 1841 by paleontologist Sir Richard Owen, who used it to refer to the "distinct tribe or sub-order of Saurian Reptiles" that were being recognized in England and around the world.
The term is derived from Ancient Greek δεινός, meaning'terrible, potent or fearfully great', σαῦρος, meaning'lizard or reptile'. Though the taxonomic name has been interpreted as a reference to dinosaurs' teeth and other fearsome characteristics, Owen intended it to evoke their size and majesty. Other prehistoric animals, including pterosaurs, ichthyosaurs and Dimetrodon, while popularly conceived of as dinosaurs, are not taxonomically classified as dinosaurs. Pterosaurs are distantly related to dinosaurs; the other groups mentioned are, like dinosaurs and pterosaurs, members of Sauropsida, except Dimetrodon. Under phylogenetic nomenclature, dinosaurs are defined as the group consisting of the most recent common ancestor of Triceratops and Neornithes, all its descendants, it has been suggested that Dinosauria be defined with respect to the MRCA of Megalosaurus and Iguanodon, because these were two of the three genera cited by Richard Owen when he recognized the Dinosauria. Both definitions result in the same set of animals being defined as dinosaurs: "Dinosauria = Ornithischia + Saurischia", encompassing ankylosaurians, ceratopsians, ornithopods and sauropodomorphs.
Birds are now recognized as being the sole surviving lineage of theropod dinosaurs. In traditional taxonomy, birds were considered a separate class that had evolved from dinosaurs, a distinct superorder. However, a majority of contemporary paleontologists concerned with dinosaurs reject the traditional style of classification in favor of phylogenetic taxonomy. Birds are thus considered to be dinosaurs and dinosaurs are, not extinct. Birds are classified as belonging to the subgroup M
The acetabular notch is a deep notch in the acetabulum of the hip bone. The acetabular notch is continuous with a circular non-articular depression, the acetabular fossa, at the bottom of the cavity: this depression is perforated by numerous apertures, lodges a mass of fat; the notch is converted into a foramen by the transverse acetabular ligament. This article incorporates text in the public domain from page 237 of the 20th edition of Gray's Anatomy Anatomy photo:17:st-1111 at the SUNY Downstate Medical Center
In ancient dining, an acetabulum was a vinegar-cup, from the fondness of the Greeks and Romans for vinegar, was always placed on the table at meals to dip the food in before eating it. The vessel was open above; the cups used by jugglers in their performances were called by this name. They were of earthenware, but sometimes of glass, bronze, or gold. In anatomy, because of its shape, the acetabulum is the place of pelvis that meets with the head of the femur, forming the hip joint; this article incorporates text from a publication now in the public domain: Smith, William, ed.. "article name needed". Dictionary of Greek and Roman Antiquities. London: John Murray
The acetabular labrum is a ring of cartilage that surrounds the acetabulum of the hip. The anterior portion is most vulnerable, it provides an articulating surface for the acetabulum, allowing the head of the femur to articulate with the pelvis. It is estimated. Tears of the labrum have been credited to a variety of causes such as excessive force, hip dislocation, capsular hip hypermobility, hip dysplasia, hip degeneration. A tight iliopsoas tendon has been attributed to labrum tears by causing compression or traction injuries that lead to a labrum tear. Most labrum tears are thought to be from gradual tear due to repetitive microtrauma. Incidents of labrum tears increase with age, suggesting that they may be caused by deterioration through the aging process. Labrum tears in athletes can occur from recurring trauma. Running can cause labrum tears due to the labrum being used more for weight bearing and taking excessive forces while at the end-range motion of the leg: hyperabduction, hyperflexion, excessive external rotation.
Sporting activities are causes those that require frequent lateral rotation or pivoting on a loaded femur as in hockey or ballet. Constant hip rotation places increased stress on the capsular tissue and damage to the iliofemoral ligament; this in turn causes hip rotational instability putting increased pressure on the labrum. Traumatic injuries are most seen in athletes who participate in contact or high impact sports like football, soccer, or golf; the prevalence rate for traumatic hip injuries that causes a tear of the labrum is low. Less than 25% of all patients can relate a specific incident to their torn labrum, however they are a result of a dislocation or fracture. Falling on one’s side causes a blunt trauma to the greater trochanter of the femur. Since there is little soft tissue to diminish the force between the impact and the greater trochanter, the entire blow is transferred to the surface of the hip joint, and since bone density does not reach its peak until the age of 30, hip traumas could result in a fracture.
Tears of the hip labrum can be classified in a variety of ways, including morphology, location, or severity. Anatomical modifications of the femur and or hip socket cause a slow buildup of damage to the cartilage. Femur or acetabular dysplasia can lead to femoral acetabular impingement. Impingement occurs when the femoral head rubs abnormally or lacks a full range of motion in the acetabular socket. There are three different forms of FAI; the first form is caused by a cam-deformity where extra bone is present on the femoral head, which leads to the head being non-spherical. The second deformity is referred to as a pincer deformity and it is due to an excess growth of the acetabular socket; the third type of FAI is a combination of the first two deformities. When either abnormality is present, it changes the position that the femoral head occupies in the hip socket; the increased stresses that the femur and or acetabulum experience may lead to a fracture of the acetabular rim or a detachment of the overstressed labrum.
In the United States acetabular labrum tears occur in the anterior or anterior-superior area due to a sudden change from labrum to acetabular cartilage. The most common labrum tears in Japan are in the posterior region due to the customary practice of sitting on the floor. Posterior labrum tears in the Western world occur when a force drives the femoral head posteriorly which transfers shear and compressive forces to the posterior labrum. With physical therapy, there is only a small amount of evidence on rehabilitation techniques for the acetabular labrum, it is thought that physical therapy could be controversial due to there not being any evidence of a specific effective therapy routine. There are, some studies that report physical therapy could benefit the patient by bringing them back to “sports-ready” capabilities, it is advised that physical therapists keep up on the new findings and stay in close contact with the orthopaedic surgeon so they have the best idea of how to approach their patient’s case.
Following surgery, crutches will be used for up to six weeks and there should be no expectation to return to activities such as running for at least a period of six months. Some things to note when rehabilitation occurs is that it is important to know the size and placement of the tear. There are four phases in the rehabilitation process noted as: “Phase I – initial exercises, Phase II – intermediate exercises, Phase III – advanced exercises, Phase IV – return to sports ”. All physical therapy regimens should be individualized from person to person based on all adequate criteriaIn phase I of the rehabilitation process the first objective is to minimize the pain and inflammation, it is important to begin conducting small motion exercises that have up to 50% weight bearing capacity by the patient. A symmetrical gait pattern is imperative as not to create an imbalance in the muscles of the hip. Aquatic therapy is encouraged and looked upon due to its ability to help the patient move more without the pressure of gravity.
To progress to phase “II” of the rehabilitation process patients should be able to complete straight leg raises while lying on their side to strengthen the sartorius and tensor fasciate latae muscles to build support in the leg. In phase “II” the physical therapist should be trying to promote more flexibility in the soft tissue. There should be more emphasis on the beginning aspects of strength training while adding some resistance
The pelvis is either the lower part of the trunk of the human body between the abdomen and the thighs or the skeleton embedded in it. The pelvic region of the trunk includes the bony pelvis, the pelvic cavity, the pelvic floor, below the pelvic cavity, the perineum, below the pelvic floor; the pelvic skeleton is formed in the area of the back, by the sacrum and the coccyx and anteriorly and to the left and right sides, by a pair of hip bones. The two hip bones connect the spine with the lower limbs, they are attached to the sacrum posteriorly, connected to each other anteriorly, joined with the two femurs at the hip joints. The gap enclosed by the bony pelvis, called the pelvic cavity, is the section of the body underneath the abdomen and consists of the reproductive organs and the rectum, while the pelvic floor at the base of the cavity assists in supporting the organs of the abdomen. In mammals, the bony pelvis has a gap in the middle larger in females than in males, their young pass through this gap.
The pelvic region of the trunk is the lower part of the trunk, between the thighs. It includes several structures: the bony pelvis, the pelvic cavity, the pelvic floor, the perineum; the bony pelvis is the part of the skeleton embedded in the pelvic region of the trunk. It is subdivided into the pelvic spine; the pelvic girdle is composed of the appendicular hip bones oriented in a ring, connects the pelvic region of the spine to the lower limbs. The pelvic spine consists of the coccyx; the pelvic cavity defined as a small part of the space enclosed by the bony pelvis, delimited by the pelvic brim above and the pelvic floor below. Each hip bone consists of 3 sections, ilium and pubis. During childhood, these sections are separate bones, joined by the triradiate cartilage. During puberty, they fuse together to form a single bone; the pelvic cavity is a body cavity, bounded by the bones of the pelvis and which contains reproductive organs and the rectum. A distinction is made between the lesser or true pelvis inferior to the terminal line, the greater or false pelvis above it.
The pelvic inlet or superior pelvic aperture, which leads into the lesser pelvis, is bordered by the promontory, the arcuate line of ilium, the iliopubic eminence, the pecten of the pubis, the upper part of the pubic symphysis. The pelvic outlet or inferior pelvic aperture is the region between the subpubic angle or pubic arch, the ischial tuberosities and the coccyx. Ligaments: obturator membrane, inguinal ligament Alternatively, the pelvis is divided into three planes: the inlet and outlet; the pelvic floor has two inherently conflicting functions: One is to close the pelvic and abdominal cavities and bear the load of the visceral organs. To achieve both these tasks, the pelvic floor is composed of several overlapping sheets of muscles and connective tissues; the pelvic diaphragm is composed of the coccygeus muscle. These arise between the symphysis and the ischial spine and converge on the coccyx and the anococcygeal ligament which spans between the tip of the coccyx and the anal hiatus; this leaves a slit for the urogenital openings.
Because of the width of the genital aperture, wider in females, a second closing mechanism is required. The urogenital diaphragm consists of the deep transverse perineal which arises from the inferior ischial and pubic rami and extends to the urogential hiatus; the urogenital diaphragm is reinforced posteriorly by the superficial transverse perineal. The external anal and urethral sphincters close the urethra; the former is surrounded by the bulbospongiosus which narrows the vaginal introitus in females and surrounds the corpus spongiosum in males. Ischiocavernosus clitoridis. Modern humans are to a large extent characterized by large brains; because the pelvis is vital to both locomotion and childbirth, natural selection has been confronted by two conflicting demands: a wide birth canal and locomotion efficiency, a conflict referred to as the "obstetrical dilemma". The female pelvis, or gynecoid pelvis, has evolved to its maximum width for childbirth—a wider pelvis would make women unable to walk.
In contrast, human male pelvises are not constrained by the need to give birth and therefore are more optimized for bipedal locomotion. The principal differences between male and female true and false pelvis include: The female pelvis is larger and broader than the male pelvis, taller and more compact; the female inlet is oval in shape, while the male sacral promontory projects further. The sides of the male pelvis converge from the inlet to the outlet, whereas the sides of the female pelvis are wider apart; the angle between
Ornithischia is an extinct clade of herbivorous dinosaurs characterized by a pelvic structure similar to that of birds. The name Ornithischia, or "bird-hipped", reflects this similarity and is derived from the Greek stem ornith-, meaning "of a bird", ischion, plural ischia, meaning "hip joint". However, birds are only distantly related to this group. Ornithischians with well known anatomical adaptations include the ceratopsians or "horn-faced" dinosaurs, armored dinosaurs such as stegosaurs and ankylosaurs, pachycephalosaurids and the ornithopods. There is strong evidence that certain groups of ornithischians lived in herds segregated by age group, with juveniles forming their own flocks separate from adults; some were at least covered in filamentous pelts, there is much debate over whether these filaments found in specimens of Tianyulong and Kulindadromeus may have been primitive feathers. In 1887, Harry Seeley divided Dinosauria into two clades: Saurischia. Ornithischia is a supported clade with an abundance of diagnostic characters.
The two most notable traits are a "bird-like" hip and beak-like predentary structure, though they shared other features as well. The ornithischian pelvis was "opisthopubic", meaning that the pubis pointed down and backwards, parallel with the ischium. Additionally, the ilium had a forward-pointing process to support the abdomen; this resulted in a four-pronged pelvic structure. In contrast to this, the saurischian pelvis was "propubic", meaning the pubis pointed toward the head, as in ancestral reptiles; the opisthopubic pelvis independently evolved at least three times in dinosaurs. Some argue that the opisthopubic pelvis evolved a fourth time, in the clade Dromaeosauridae, but this is controversial, as other authors argue that dromaeosaurids are mesopubic. Ornithischians shared; this unpaired bone was situated at the front of the lower jaw. The predentary coincided with the premaxilla in the upper jaw. Together, they formed a beak-like apparatus used to clip off plant material. In ceratopsian dinosaurs, it opposed the rostral bone.
In 2017 Baron & Barrett suggested that Chilesaurus may represent an early diverging ornithischian that had not yet acquired the predentary of all other ornithischians. Ornithischians had paired premaxillary bones that were toothless and roughened at the tip of the snout. Ornithischians developed a narrow "eyebrow", or palpebral bone, across the outside of the eye socket. Ornithischians had reduced, or closed-off, antorbital fenestrae. Ornithischian jaw joints were lowered below the level of the teeth, bringing the teeth into simultaneous occlusion. Ornithischians had "leaf-shaped" cheek teeth. Ornithischian backbones were stiffened near the pelvis by the ossification of tendons above the sacrum. Additionally, ornithischians had at least five sacral vertebrae attaching to the pelvis. Ornithischia is a branch-based taxon defined as all dinosaurs more related to Triceratops horridus Marsh, 1889 than to either Passer domesticus or Saltasaurus loricatus Bonaparte & Powell, 1980. Genasauria comprises the clades Neornithischia.
Thyreophora includes Ankylosauria. Neornithischia comprises several basal taxa and Ornithopoda. Cerapoda is a recent concept; the cladogram below follows a 2009 analysis by colleagues. All tested. Cladogram after Butler et al. 2011. Ornithopoda includes Hypsilophodon and others; the exact placement of Ornithischia within the dinosaur lineage is a contentious issue. Traditionally, Ornithischia is considered the sister group of Saurischia. However, in the alternative hypothesis of dinosaur relationships, proposed by Baron, Norman & Barrett in the journal Nature in 2017, Ornithischia was recovered as the sister group to the Theropoda, which grouped together in the clade Ornithoscelida; this hypothesis was challenged by an international consortium of early dinosaur experts led by Max Langer. However, the data that supported the more traditional placement of Ornithischia, as sister taxon of Saurischia, was found not to be statistically significant from the evidence that supported the Ornithoscelida hypothesis, in both the study by Langer et al. and the reply to the study by Baron et al.
A further 2017 study found some support for the abandoned Phytodinosauria model, which classifies ornithischians together with sauropodomorphs. Ornithischians shifted from bipedal to quadrupedal posture at least three times in their evolutionary history and it has been shown primitive members may have been capable of both forms of movement. Most ornithischians were herbivorous. In fact, most of the unifying characters of Ornithischia are thought to be related to this herbivory. For example, the shift to an opisthopubic pelvis is thought to be related to the development of a large stomach or stomachs and gut which would allow ornithischians to digest plant matter better; the smallest known ornithischian is Fruitadens haagarorum. The largest Fruitadens individuals reached just 65–75 cm. Only carnivorous, sa