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Facial Symmetry
Facial symmetry is one specific measure of bodily symmetry. Along with traits such as averageness and youthfulness, it influences judgments of aesthetic traits of physical attractiveness and beauty. For instance, in mate selection, people have been shown to have a preference for symmetry. Facial bilateral symmetry is typically defined as fluctuating asymmetry of the face comparing random differences in facial features of the two sides of the face. The human face also has systematic, directional asymmetry: on average, the face (mouth, nose and eyes) sits systematically to the left with respect to the axis through the ears, the so-called ''aurofacial asymmetry''. Directional asymmetry Directional asymmetry is systematic. The average across the population is not "symmetric", but statistically significantly Bias (statistics), biased on one direction. That means, that individuals of a species can be symmetric, or even asymmetric to the opposite side (see, e.g., handedness), but mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symmetry
Symmetry () in everyday life refers to a sense of harmonious and beautiful proportion and balance. In mathematics, the term has a more precise definition and is usually used to refer to an object that is Invariant (mathematics), invariant under some Transformation (function), transformations, such as Translation (geometry), translation, Reflection (mathematics), reflection, Rotation (mathematics), rotation, or Scaling (geometry), scaling. Although these two meanings of the word can sometimes be told apart, they are intricately related, and hence are discussed together in this article. Mathematical symmetry may be observed with respect to the passage of time; as a space, spatial relationship; through geometric transformations; through other kinds of functional transformations; and as an aspect of abstract objects, including scientific model, theoretic models, language, and music. This article describes symmetry from three perspectives: in mathematics, including geometry, the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axial Twist Theory
The axial twist theory (wiktionary:also known as, a.k.a. axial twist ''hypothesis'') is a proposed scientific theory that has been proposed to explain a range of unusual aspects of the body plan of vertebrates (including humans). It states that the Rostral (anatomical term), rostral part of the head is "turned around" regarding the rest of the body. This end-part consists of the face (eyes, nose, and mouth) as well as part of the brain (cerebrum and thalamus). According to the theory, the vertebrate body has a left-handed chirality#Biology, chirality. The axial twist theory competes with a Axial twist theory#Relation to other theories and hypotheses, number of other proposals that focus on more limited, specific aspects, most of which explain Contralateral brain, contralateral forebrain organization, the phenomenon that the left side of the brain mainly controls the right side of the body and vice versa. None of the proposed theories explaining this phenomenon, including axial twis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canthus
The canthus (: canthi, palpebral commissures) is either corner of the eye where the upper and lower eyelids meet. More specifically, the inner and outer canthi are, respectively, the medial and lateral ends/angles of the palpebral fissure. The bicanthal plane is the transversal plane linking both canthi and defines the upper boundary of the midface. Etymology The word ' is the Latinized form of the Ancient Greek ('), meaning 'corner of the eye'. Population distribution The eyes of East Asian and some Southeast Asian people tend to have the inner canthus veiled by the epicanthus. In the Caucasian or double eyelid, the inner corner tends to be exposed completely. Commissures * The ''lateral palpebral commissure'' (commissura palpebrarum lateralis; external canthus) is more acute than the medial, and the eyelids here lie in close contact with the bulb of the eye. * The ''medial palpebral commissure'' (commissura palpebrarum medialis; internal canthus) is prolonged for a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Degree (angle)
A degree (in full, a degree of arc, arc degree, or arcdegree), usually denoted by ° (the degree symbol), is a measurement of a plane (mathematics), plane angle in which one Turn (geometry), full rotation is 360 degrees. It is not an SI unit—the SI unit of angular measure is the radian—but it is mentioned in the SI Brochure, SI brochure as an Non-SI units mentioned in the SI, accepted unit. Because a full rotation equals 2 radians, one degree is equivalent to radians. History The original motivation for choosing the degree as a unit of rotations and angles is unknown. One theory states that it is related to the fact that 360 is approximately the number of days in a year. Ancient astronomers noticed that the sun, which follows through the ecliptic path over the course of the year, seems to advance in its path by approximately one degree each day. Some ancient calendars, such as the Iranian calendar, Persian calendar and the Babylonian calendar, used 360 days for a year. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angle
In Euclidean geometry, an angle can refer to a number of concepts relating to the intersection of two straight Line (geometry), lines at a Point (geometry), point. Formally, an angle is a figure lying in a Euclidean plane, plane formed by two Ray (geometry), rays, called the ''Side (plane geometry), sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), vertex'' of the angle. More generally angles are also formed wherever two lines, rays or line segments come together, such as at the corners of triangles and other polygons. An angle can be considered as the region of the plane bounded by the sides. Angles can also be formed by the intersection of two planes or by two intersecting curves, in which case the rays lying tangent to each curve at the point of intersection define the angle. The term ''angle'' is also used for the size, magnitude (mathematics), magnitude or Physical quantity, quantity of these types of geometric figures and in this context an a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Median Plane
Whether in reference to the anatomy of the human or other members of the Bilateria, the median plane, also called the midsagittal plane and related terms, is used to describe the sagittal plane as it bisects the body vertically through the midline marked by the navel, dividing the body exactly in left and right side. The term parasagittal plane is used to refer to any plane parallel to the sagittal and median plane. It is one of the lines used to define the right upper quadrant of the human abdomen. The midsternal line can be interpreted as a segment of the median plane. File:Sagittal brain MRI.jpg, Median plane magnetic resonance imaging of the head. File:Median plane CT scan of a pregnancy of 37 weeks of gestational age.jpg, Median plane CT scan of a pregnant woman. The fetus (exposed in the coronal plane The dorsal plane (also known as the coronal plane or frontal plane, especially in human anatomy) is an anatomical plane that divides the body into Anatomical terms of l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bias
Bias is a disproportionate weight ''in favor of'' or ''against'' an idea or thing, usually in a way that is inaccurate, closed-minded, prejudicial, or unfair. Biases can be innate or learned. People may develop biases for or against an individual, a group, or a belief. In science and engineering, a bias is a systematic error. Statistical bias results from an unfair sampling of a population, or from an estimation process that does not give accurate results on average. Etymology The word appears to derive from Old Provençal into Old French ''biais'', "sideways, askance, against the grain". Whence comes French ''biais'', "a slant, a slope, an oblique". It seems to have entered English via the game of bowls">English (language)">English via the game of bowls, where it referred to balls made with a greater weight on one side. Which expanded to the figurative use, "a one-sided tendency of the mind", and, at first especially in law, "undue propensity or prejudice". or ballast, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Development (biology)
Development of the human body is the process of growth to maturity. The process begins with fertilization, where an egg released from the ovary of a female is penetrated by a sperm cell from a male. The resulting zygote develops through mitosis and cell differentiation, and the resulting embryo then implants in the uterus, where the embryo continues development through a fetal stage until birth. Further growth and development continues after birth, and includes both physical and psychological development that is influenced by genetic, hormonal, environmental and other factors. This continues throughout life: through childhood and adolescence into adulthood. Before birth Development before birth, or prenatal development () is the process in which a zygote, and later an embryo, and then a fetus develops during gestation. Prenatal development starts with fertilization and the formation of the zygote, the first stage in embryonic development which continues in fetal de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mouth
A mouth also referred to as the oral is the body orifice through which many animals ingest food and animal communication#Auditory, vocalize. The body cavity immediately behind the mouth opening, known as the oral cavity (or in Latin), is also the first part of the alimentary canal, which leads to the pharynx and the gullet. In tetrapod vertebrates, the mouth is bounded on the outside by the lips and cheeks — thus the oral cavity is also known as the buccal cavity (from Latin ', meaning "cheek") — and contains the tongue on the inside. Except for some groups like birds and lissamphibians, vertebrates usually have teeth in their mouths, although some fish species have pharyngeal teeth instead of oral teeth. Most bilaterian phylum, phyla, including arthropods, molluscs and chordates, have a two-opening gut tube with a mouth at one end and an anus at the other. Which end forms first in ontogeny is a criterion used to classify bilaterian animals into protostomes and deuterostomes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nose
A nose is a sensory organ and respiratory structure in vertebrates. It consists of a nasal cavity inside the head, and an external nose on the face. The external nose houses the nostrils, or nares, a pair of tubes providing airflow through the nose for Respiration (physiology), respiration. Where the nostrils pass through the nasal cavity they widen, are known as nasal fossae, and contain nasal concha, turbinates and olfactory mucosa. The nasal cavity also connects to the paranasal sinuses (dead-end air cavities for pressure buffering and humidification). From the nasal cavity, the nostrils continue into the pharynx, a switch track valve connecting the respiratory system, respiratory and digestive systems. In humans, the nose is located centrally on the face and serves as an alternative respiratory passage especially during suckling for infants. The protruding nose that is completely separate from the mouth part is a characteristic found only in theria, therian mammals. It has b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eyes
An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the eye is a complex optical system that collects light from the surrounding environment, regulates its intensity through a diaphragm, focuses it through an adjustable assembly of lenses to form an image, converts this image into a set of electrical signals, and transmits these signals to the brain through neural pathways that connect the eye via the optic nerve to the visual cortex and other areas of the brain. Eyes with resolving power have come in ten fundamentally different forms, classified into compound eyes and non-compound eyes. Compound eyes are made up of multiple small visual units, and are common on insects and crustaceans. Non-compound eyes have a single lens and focus light onto the retina to form a single image. This type of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Face
The face is the front of the head that features the eyes, nose and mouth, and through which animals express many of their emotions. The face is crucial for human identity, and damage such as scarring or developmental deformities may affect the psyche adversely. Structure The front of the human head is called the face. It includes several distinct areas, of which the main features are: *The forehead, comprising the skin beneath the hairline, bordered laterally by the temples and inferiorly by eyebrows and ears *The eyes, sitting in the orbit and protected by eyelids and eyelashes * The distinctive human nose shape, nostrils, and nasal septum *The cheeks, covering the maxilla and mandible (or jaw), the extremity of which is the chin *The mouth, with the upper lip divided by the philtrum, sometimes revealing the teeth Facial appearance is vital for human recognition and communication. Facial muscles in humans allow expression of emotions. The face is itself a highly s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
