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Risorius
The risorius muscle is a muscle of facial expression. It arises from the fascia over the parotid gland, and inserts into the angle of the mouth. It is supplied by the facial nerve (CN VII). It may be absent or asymmetrical in some people. It retracts the angle of the mouth during smiling. Structure The risorius muscle arises in the fascia over the parotid gland. Passing horizontally forward, superficial to the platysma muscle, it inserts onto the skin at the angle of the mouth. It is a narrow bundle of fibers, broadest at its origin, but varies much in its size and form. It is superficial to the masseter muscle, partially covering it. Nerve supply Like all muscles of facial expression, the risorius is supplied by the facial nerve (CN VII). The specific branch is debated, with some sources giving marginal mandibular branch of the facial nerve and others giving buccal branch of the facial nerve. Development It has been suggested that the risorius muscle is only found in Hominin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facial Artery
The facial artery (external maxillary artery in older texts) is a branch of the external carotid artery that supplies structures of the superficial face. Structure The facial artery arises in the carotid triangle from the external carotid artery, a little above the lingual artery and, sheltered by the ramus of the mandible. It passes obliquely up beneath the digastric and stylohyoid muscles, over which it arches to enter a groove on the posterior surface of the submandibular gland. It then curves upward over the body of the mandible at the antero-inferior angle of the masseter; passes forward and upward across the cheek to the angle of the mouth, then ascends along the side of the nose, and ends at the medial commissure of the eye, under the name of the angular artery. The facial artery is remarkably tortuous. This is to accommodate itself to neck movements such as those of the pharynx in deglutition; and facial movements such as those of the mandible, lips, and cheeks. Re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parotid
The parotid gland is a major salivary gland in many animals. In humans, the two parotid glands are present on either side of the mouth and in front of both ears. They are the largest of the salivary glands. Each parotid is wrapped around the mandibular ramus, and secretes serous saliva through the parotid duct into the mouth, to facilitate mastication and swallowing and to begin the digestion of starches. There are also two other types of salivary glands; they are submandibular and sublingual glands. Sometimes accessory parotid glands are found close to the main parotid glands. Etymology The word ''parotid'' literally means "beside the ear". From Greek παρωτίς (stem παρωτιδ-) : (gland) behind the ear < παρά - pará : in front, and οὖς - ous (stem ὠτ-, ōt-) : ear. Structure The parotid glands are a pair of mainly |
Modiolus (face)
In facial anatomy, the modiolus is a chiasma of facial muscles held together by fibrous tissue, located lateral and slightly superior to each angle of the mouth. It is important in moving the mouth, facial expression and in dentistry. It is extremely important in relation to stability of lower denture, because of the strength and variability of movement of the area. It derives its motor nerve supply from the facial nerve, and its blood supply from labial branches of the facial artery. It is contributed to by the following muscles: orbicularis oris, buccinator, levator anguli oris, depressor anguli oris, zygomaticus major, risorius, quadratus labii superioris, quadratus labii inferioris The depressor labii inferioris (or quadratus labii inferioris) is a facial muscle. It helps to lower the bottom lip. Structure The depressor labii inferioris muscle arises from the lateral surface of the mandible. This is below the mental for ....Drake, Vogl, Mitchell. Gray's Anatomy For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parotid Gland
The parotid gland is a major salivary gland in many animals. In humans, the two parotid glands are present on either side of the mouth and in front of both ears. They are the largest of the salivary glands. Each parotid is wrapped around the mandibular ramus, and secretes serous saliva through the parotid duct into the mouth, to facilitate mastication and swallowing and to begin the digestion of starches. There are also two other types of salivary glands; they are submandibular and sublingual glands. Sometimes accessory parotid glands are found close to the main parotid glands. Etymology The word ''parotid'' literally means "beside the ear". From Greek παρωτίς (stem παρωτιδ-) : (gland) behind the ear < παρά - pará : in front, and οὖς - ous (stem ὠτ-, ōt-) : ear. Structure The parotid glands are a pair of mainly serous salivary gland ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homininae
Homininae (), also called "African hominids" or "African apes", is a subfamily of Hominidae. It includes two tribes, with their extant as well as extinct species: 1) the tribe Hominini (with the genus ''Homo'' including modern humans and numerous extinct species; the subtribe Hominina, comprising at least two extinct genera; and the subtribe Panina, represented only by the genus ''Pan'', which includes chimpanzees and bonobos)―and 2) the tribe Gorillini (gorillas). Alternatively, the genus '' Pan'' is sometimes considered to belong to its own third tribe, Panini. Homininae comprises all hominids that arose after orangutans (subfamily Ponginae) split from the line of great apes. The Homininae cladogram has three main branches, which lead to gorillas (through the tribe Gorillini), and to humans and chimpanzees via the tribe Hominini and subtribes Hominina and Panina (see the evolutionary tree below). There are two living species of Panina (chimpanzees and bonobos) and two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygomaticus Minor
The zygomaticus minor muscle is a muscle of facial expression. It originates from the zygomatic bone, lateral to the rest of the levator labii superioris muscle, and inserts into the outer part of the upper lip. It draws the upper lip backward, upward, and outward and is used in smiling. It is innervated by the facial nerve (VII). Structure The zygomaticus minor muscle originates from the zygomatic bone. It inserts into the tissue around the upper lip, particularly blending its fibres with orbicularis oris muscle. It lies lateral to the rest of levator labii superioris muscle, and medial to its stronger synergist zygomaticus major muscle. It travels at an angle of approximately 30°. It has a mean width of around 0.5 cm. Nerve supply The zygomaticus minor muscle is supplied by the buccal branch of the facial nerve (VII). Variation The zygomaticus minor muscle may have either a straight or a curved course along its length. It may attach to both the upper lip and the lat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygomaticus Major
The zygomaticus major muscle is a muscle of the human body. It extends from each zygomatic arch (cheekbone) to the corners of the mouth. It is a muscle of facial expression which draws the angle of the mouth superiorly and posteriorly to allow one to smile. Bifid zygomaticus major muscle is a notable variant, and may cause cheek dimples. Structure The zygomaticus major muscle originates from the upper margin of the temporal process, part of the lateral surface of the zygomatic bone. It inserts into tissue at the corner of the mouth. Nerve supply The zygomaticus major muscle is supplied by a buccal branch and a zygomatic branch of the facial nerve (VII). Variation The zygomaticus major muscle may occur in a bifid form, with two fascicles that are partially or completely separate from each other but adjacent. Usually a single unit, dimple A dimple, also called a gelasin (, ) is a small natural indentation in the flesh on a part of the human body, most notably in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elsevier
Elsevier () is a Dutch academic publishing company specializing in scientific, technical, and medical content. Its products include journals such as '' The Lancet'', '' Cell'', the ScienceDirect collection of electronic journals, '' Trends'', the '' Current Opinion'' series, the online citation database Scopus, the SciVal tool for measuring research performance, the ClinicalKey search engine for clinicians, and the ClinicalPath evidence-based cancer care service. Elsevier's products and services also include digital tools for data management, instruction, research analytics and assessment. Elsevier is part of the RELX Group (known until 2015 as Reed Elsevier), a publicly traded company. According to RELX reports, in 2021 Elsevier published more than 600,000 articles annually in over 2,700 journals; as of 2018 its archives contained over 17 million documents and 40,000 e-books, with over one billion annual downloads. Researchers have criticized Elsevier for its high profit ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smile
A smile is a facial expression formed primarily by flexing the muscles at the sides of the mouth. Some smiles include a contraction of the muscles at the corner of the eyes, an action known as a Duchenne smile. Among humans, a smile expresses delight, sociability, happiness, joy, or amusement. It is distinct from a similar but usually involuntary expression of anxiety known as a grimace. Although cross-cultural studies have shown that smiling is a means of communication throughout the world, there are large differences among different cultures, religions, and societies, with some using smiles to convey confusion or embarrassment. Evolutionary background Primatologist Signe Preuschoft traces the smile back over 30 million years of evolution to a "fear grin" stemming from monkeys and apes, who often used barely clenched teeth to portray to predators that they were harmless or to signal submission to more dominant group members. The smile may have evolved differently among spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymmetry
Asymmetry is the absence of, or a violation of, symmetry (the property of an object being invariant to a transformation, such as reflection). Symmetry is an important property of both physical and abstract systems and it may be displayed in precise terms or in more aesthetic terms. The absence of or violation of symmetry that are either expected or desired can have important consequences for a system. In organisms Due to how cell (biology), cells divide in organisms, asymmetry in organisms is fairly usual in at least one dimension, with symmetry (biology), biological symmetry also being common in at least one dimension. Louis Pasteur proposed that biological molecules are asymmetric because the cosmic [i.e. physical] forces that preside over their formation are themselves asymmetric. While at his time, and even now, the symmetry of physical processes are highlighted, it is known that there are fundamental physical asymmetries, starting with time. Asymmetry in biology Asym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, and language. Humans are highly social and tend to live in complex social structures composed of many cooperating and competing groups, from families and kinship networks to political states. Social interactions between humans have established a wide variety of values, social norms, and rituals, which bolster human society. Its intelligence and its desire to understand and influence the environment and to explain and manipulate phenomena have motivated humanity's development of science, philosophy, mythology, religion, and other fields of study. Although some scientists equate the term ''humans'' with all members of the genus ''Homo'', in common usage, it generally refers to ''Homo sapiens'', the only Extant taxon, extant member. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Masseter Muscle
In human anatomy, the masseter is one of the muscles of mastication. Found only in mammals, it is particularly powerful in herbivores to facilitate chewing of plant matter. The most obvious muscle of mastication is the masseter muscle, since it is the most superficial and one of the strongest. Structure The masseter is a thick, somewhat quadrilateral muscle, consisting of three heads, superficial, deep and coronoid. The fibers of superficial and deep heads are continuous at their insertion. Superficial head The superficial head, the larger, arises by a thick, tendinous aponeurosis from the temporal process of the zygomatic bone, and from the anterior two-thirds of the inferior border of the zygomatic arch. Its fibers pass inferior and posterior, to be inserted into the angle of the mandible and inferior half of the lateral surface of the ramus of the mandible. Deep head The deep head is much smaller, and more muscular in texture. It arises from the posterior third of the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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