|
Rhomboidal Nucleus
Traditionally, in two-dimensional geometry, a rhomboid is a parallelogram in which adjacent sides are of unequal lengths and angles are non-right angled. The terms "rhomboid" and "parallelogram" are often erroneously conflated with each other (i.e, when most people refer to a "parallelogram" they almost always mean a rhomboid, a specific subtype of parallelogram); however, while all rhomboids are parallelograms, not all parallelograms are rhomboids. A parallelogram with sides of equal length (equilateral) is called a ''rhombus'' but not a rhomboid. A parallelogram with right angled corners is a ''rectangle'' but not a rhomboid. A parallelogram is a rhomboid if it is neither a rhombus nor a rectangle. History Euclid introduced the term in his '' Elements'' in Book 1, Definition 22, Euclid never used the definition of rhomboid again and introduced the word parallelogram in Proposition 34 of Book 1; ''"In parallelogrammic areas the opposite sides and angles are equal to one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parallelogram
In Euclidean geometry, a parallelogram is a simple polygon, simple (non-list of self-intersecting polygons, self-intersecting) quadrilateral with two pairs of Parallel (geometry), parallel sides. The opposite or facing sides of a parallelogram are of equal length and the opposite angles of a parallelogram are of equal measure. The congruence (geometry), congruence of opposite sides and opposite angles is a direct consequence of the Euclidean parallel postulate and neither condition can be proven without appealing to the Euclidean parallel postulate or one of its equivalent formulations. By comparison, a quadrilateral with at least one pair of parallel sides is a trapezoid in American English or a trapezium in British English. The three-dimensional counterpart of a parallelogram is a parallelepiped. The word "parallelogram" comes from the Greek παραλληλό-γραμμον, ''parallēló-grammon'', which means "a shape of parallel lines". Special cases *Rectangle – A par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David E
David (; , "beloved one") was a king of ancient Israel and Judah and the third king of the United Monarchy, according to the Hebrew Bible and Old Testament. The Tel Dan stele, an Aramaic-inscribed stone erected by a king of Aram-Damascus in the late 9th/early 8th centuries BCE to commemorate a victory over two enemy kings, contains the phrase (), which is translated as " House of David" by most scholars. The Mesha Stele, erected by King Mesha of Moab in the 9th century BCE, may also refer to the "House of David", although this is disputed. According to Jewish works such as the '' Seder Olam Rabbah'', '' Seder Olam Zutta'', and '' Sefer ha-Qabbalah'' (all written over a thousand years later), David ascended the throne as the king of Judah in 885 BCE. Apart from this, all that is known of David comes from biblical literature, the historicity of which has been extensively challenged,Writing and Rewriting the Story of Solomon in Ancient Israel; by Isaac Kalimi; pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhomboid Major Muscle
The rhomboid major is a skeletal muscle of the back that connects the scapula with the vertebrae of the spinal column. It originates from the spinous processes of the thoracic vertebrae T2–T5 and supraspinous ligament; it inserts onto the lower portion of the Medial border of scapula, medial border of the scapula. It acts together with the Rhomboid minor muscle, rhomboid minor to keep the scapula pressed against thoracic wall and to retract the scapula toward the vertebral column. As the word ''rhomboid'' suggests, the rhomboid major is diamond-shaped. The ''major'' in its name indicates that it is the larger of the two rhomboids. Structure Origin The rhomboid major arises from the spinous processes of the thoracic vertebrae T2–T5 as well as the supraspinous ligament. Insertion It inserts on the Medial border of scapula, medial border of the scapula, from about the level of the scapular spine to the scapula's inferior angle. Innervation The rhomboid major, like the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthrocentesis
Arthrocentesis, or joint aspiration, is the clinical procedure performed to diagnose and, in some cases, treat musculoskeletal conditions. The procedure entails using a syringe to collect synovial fluid from or inject medication into the joint capsule. Laboratory analysis of synovial fluid can further help characterize the diseased joint and distinguish between gout, arthritis, and synovial infections such as septic arthritis. Uses In general, arthrocentesis should be strongly considered if there is suspected trauma, infection, or effusion of the joint. Diagnostic Arthrocentesis can be used to diagnose septic arthritis or crystal arthropathy. In the case of a septic joint, arthrocentesis should preferably be performed prior to starting treatment with antibiotics, in order to ensure a proper sample of synovial fluid is obtained. Synovial Fluid Analysis Patients with a fever, suspected flare of existing arthritis, or unknown cause of joint effusion should undergo arthrocen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Pyrophosphate
Calcium pyrophosphate refers to any member of a series of inorganic compound with the formula . They are white solids that are insoluble in water. They contain the pyrophosphate anion, although sometimes they are referred to as phosphates. The inventory includes an anhydrous form, a dihydrate (Ca2P2O7·2H2O), and a tetrahydrate (Ca2P2O7·4H2O). Deposition of dihydrate crystals in cartilage are responsible for the severe joint pain in cases of calcium pyrophosphate deposition disease (pseudo gout) whose symptoms are similar to those of gout. Ca2P2O7 is commonly used as a mild abrasive agent in toothpastes because of its insolubility and nonreactivity toward fluoride. __TOC__ Preparation Crystals of the tetrahydrate can be prepared by treating a solution of sodium pyrophosphate with calcium nitrate with careful control of pH and temperature: :Na4P2O7(aq)+2 Ca(NO3)2(aq)→ Ca2P2O7·4 H2O + 4 NaNO3 The dihydrate, sometimes termed CPPD, can be formed by the reaction of pyrophosphori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudogout
Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease, also known as pseudogout and pyrophosphate arthropathy, is a rheumatologic disease which is thought to be secondary to abnormal accumulation of calcium pyrophosphate dihydrate crystals within joint soft tissues. The knee joint is most commonly affected. The disease is metabolic in origin and its treatment remains symptomatic. Signs and symptoms When symptomatic, the disease classically begins with symptoms that are similar to a gout attack (thus the moniker ''pseudogout''). These include: * severe pain * warmth * swelling of one or more joints * severe fatigue * fever * feeling of malaise or flu-like symptoms * inability to walk or perform everyday tasks or hobbies * gnawing/chewing sensations in the joints * burning The symptoms can be monoarticular (involving a single joint) or polyarticular (involving several joints). Symptoms usually last for days to weeks, and often recur. Although any joint may be affec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalopod Fin
Cephalopod fins, sometimes known as wings,Young, R.E., M. Vecchione & K.M. Mangold (1999)Cephalopoda Glossary Tree of Life Web Project. are paired fin, flap-like locomotory appendages. They are found in Decapodiformes, ten-limbed cephalopods (including squid, bobtail squid, cuttlefish, and ''Spirula'') as well as in the Octopodiformes, eight-limbed Cirrina, cirrate octopuses and vampire squid. Many extinct cephalopod groups also possessed fins. Nautiluses and the more familiar Incirrina, incirrate octopuses lack swimming fins. An extreme development of the cephalopod fin is seen in the bigfin squid of the family Magnapinnidae. Fins project from the mantle (mollusc), mantle and are often positioned Dorsal (anatomy), dorsally. In most cephalopods, the fins are restricted to the posterior end of the mantle, but in cuttlefish and some squid they span the mantle's entire length. Fin attachment varies greatly among cephalopods, though in all cases it involves specialised fin cartilage (w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossary Of Leaf Morphology
The following terms are used to describe leaf plant morphology, morphology in the description and taxonomy (biology), taxonomy of plants. Leaves may be simple (that is, the leaf blade or 'lamina' is undivided) or compound (that is, the leaf blade is divided into two or more leaflet (botany), leaflets). The edge of the leaf may be regular or irregular, and may be smooth or have hair, bristles, or spines. For more terms describing other aspects of leaves besides their overall morphology see the leaf#Terminology, leaf article. The terms listed here all are supported by technical and professional usage, but they cannot be represented as mandatory or undebatable; readers must use their judgement. Authors often use terms arbitrarily, or coin them to taste, possibly in ignorance of established terms, and it is not always clear whether because of ignorance, or personal preference, or because usages change with time or context, or because of variation between specimens, even specimens from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kite (geometry)
In Euclidean geometry, a kite is a quadrilateral with reflection symmetry across a diagonal. Because of this symmetry, a kite has two equal angles and two pairs of adjacent equal-length sides. Kites are also known as deltoids, but the word ''deltoid'' may also refer to a deltoid curve, an unrelated geometric object sometimes studied in connection with quadrilaterals.See H. S. M. Coxeter's review of in : "It is unfortunate that the author uses, instead of 'kite', the name 'deltoid', which belongs more properly to a curve, the three-cusped hypocycloid." A kite may also be called a dart, particularly if it is not convex. Every kite is an orthodiagonal quadrilateral (its diagonals are at right angles) and, when convex, a tangential quadrilateral (its sides are tangent to an inscribed circle). The convex kites are exactly the quadrilaterals that are both orthodiagonal and tangential. They include as special cases the right kites, with two opposite right angles; the rhombus, rhombi, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhomboid Muscles
The rhomboid muscles (), often simply called the rhomboids, are rhombus-shaped muscles associated with the scapula. There are two rhomboid muscles on each side of the upper back: * Rhomboid major muscle * Rhomboid minor muscle The large rhombus-shaped muscle, located under the trapezius muscle, in the upper part of the thoracic region of the back, and the small muscle, in the same way, participate in the movement of the scapula. Their functions are the following: * Drawing scapula superomedially * Supporting scapula * Rotating glenoid cavity inferiorly Both muscles are innervated by the dorsal scapular nerve, a branch of the brachial plexus. Additional images File:Rhomboid muscles animation small.gif, Rhomboid muscles. File:Muscles rhomboïdes.jpg, Rhomboid muscles. File:Gray203.png, Left scapula The scapula (: scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotational Symmetry
Rotational symmetry, also known as radial symmetry in geometry, is the property a shape (geometry), shape has when it looks the same after some rotation (mathematics), rotation by a partial turn (angle), turn. An object's degree of rotational symmetry is the number of distinct Orientation (geometry), orientations in which it looks exactly the same for each rotation. Certain geometric objects are partially symmetrical when rotated at certain angles such as squares rotated 90°, however the only geometric objects that are fully rotationally symmetric at any angle are spheres, circles and other spheroids. Formal treatment Formally the rotational symmetry is symmetry with respect to some or all rotations in -dimensional Euclidean space. Rotations are Euclidean group#Direct and indirect isometries, direct isometries, i.e., Isometry, isometries preserving Orientation (mathematics), orientation. Therefore, a symmetry group of rotational symmetry is a subgroup of (see Euclidean g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euclid's Elements
The ''Elements'' ( ) is a mathematics, mathematical treatise written 300 BC by the Ancient Greek mathematics, Ancient Greek mathematician Euclid. ''Elements'' is the oldest extant large-scale deductive treatment of mathematics. Drawing on the works of earlier mathematicians such as Hippocrates of Chios, Eudoxus of Cnidus and Theaetetus (mathematician), Theaetetus, the ''Elements'' is a collection in 13 books of definitions, postulates, propositions and mathematical proofs that covers plane and solid Euclidean geometry, elementary number theory, and Commensurability (mathematics), incommensurable lines. These include Pythagorean theorem, Thales' theorem, the Euclidean algorithm for greatest common divisors, Euclid's theorem that there are infinitely many prime numbers, and the Compass-and-straightedge construction, construction of regular polygons and Regular polyhedra, polyhedra. Often referred to as the most successful textbook ever written, the ''Elements'' has continued to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
