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Canthi
The canthus (pl. 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 those 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 prolon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epicanthus
An epicanthic fold or epicanthus is a skin fold of the upper eyelid that covers the inner corner (medial canthus) of the eye. However, variation occurs in the nature of this feature and the possession of "partial epicanthic folds" or "slight epicanthic folds" is noted in the relevant literature.Lang, Berel (ed.) (2000) ''Race and Racism in Theory and Practice'', Rowman & Littlefield, p. 10 Various factors influence whether epicanthic folds form, including ancestry, age, and certain medical conditions. Etymology ''Epicanthus'' means 'above the canthus', with epi-canthus being the Latinized form of the Ancient Greek : 'corner of the eye'. Classification Variation in the shape of the epicanthic fold has led to four types being recognised: * ''Epicanthus supraciliaris'' runs from the brow, curving downwards towards the lachrymal sac. * ''Epicanthus palpebralis'' begins above the upper tarsus and extends to the inferior orbital rim. * ''Epicanthus tarsalis'' originates at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epicanthic Fold
An epicanthic fold or epicanthus is a skin fold of the upper eyelid that covers the inner corner (medial canthus) of the eye. However, variation occurs in the nature of this feature and the possession of "partial epicanthic folds" or "slight epicanthic folds" is noted in the relevant literature.Lang, Berel (ed.) (2000) ''Race and Racism in Theory and Practice'', Rowman & Littlefield, p. 10 Various factors influence whether epicanthic folds form, including ancestry, age, and certain medical conditions. Etymology ''Epicanthus'' means 'above the canthus', with epi-canthus being the Latinized form of the Ancient Greek : 'corner of the eye'. Classification Variation in the shape of the epicanthic fold has led to four types being recognised: * ''Epicanthus supraciliaris'' runs from the brow, curving downwards towards the lachrymal sac. * ''Epicanthus palpebralis'' begins above the upper tarsus and extends to the inferior orbital rim. * ''Epicanthus tarsalis'' originates at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eyelids
An eyelid is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. The human eyelid features a row of eyelashes along the eyelid margin, which serve to heighten the protection of the eye from dust and foreign debris, as well as from perspiration. "Palpebral" (and "blepharal") means relating to the eyelids. Its key function is to regularly spread the tears and other secretions on the eye surface to keep it moist, since the cornea must be continuously moist. They keep the eyes from drying out when asleep. Moreover, the blink reflex protects the eye from foreign bodies. The appearance of the human upper eyelid often varies between different populations. The prevalence of an epicanthic fold covering the inner corner of the eye account for the majority of East Asian and Southeast Asian populations, and is also found i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nasal Bridge
The nasal bridge is the upper, bony part of the human nose, which overlies the nasal bones. Association with epicanthic folds Low-rooted nasal bridges are closely associated with epicanthic folds. A lower nasal bridge is more likely to cause an epicanthic fold, and vice versa. Dysmorphology A lower or higher than average nasal bridge can be a sign of various genetic disorders, such as fetal alcohol syndrome. A flat nasal bridge can be a sign of Down syndrome (Trisomy 21), Fragile X syndrome, 48,XXXY variant Klinefelter syndrome, or Bartarlla-Scott syndrome. An appearance of a widened nasal bridge can be seen with dystopia canthorum, which is a lateral displacement of the inner canthi of the eyes. from UTMB, Dept. of Otolaryngology. DATE: March 17, 2004. RESIDENT PHYSICIAN: Jing Shen. F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eyelid
An eyelid is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. The human eyelid features a row of eyelashes along the eyelid margin, which serve to heighten the protection of the eye from dust and foreign debris, as well as from perspiration. "Palpebral" (and "blepharal") means relating to the eyelids. Its key function is to regularly spread the tears and other secretions on the eye surface to keep it moist, since the cornea must be continuously moist. They keep the eyes from drying out when asleep. Moreover, the blink reflex protects the eye from foreign bodies. The appearance of the human upper eyelid often varies between different populations. The prevalence of an epicanthic fold covering the inner corner of the eye account for the majority of East Asian and Southeast Asian populations, and is also found i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalometric Analysis
Cephalometric analysis is the clinical application of cephalometry. It is analysis of the dental and skeletal relationships of a human skull. It is frequently used by dentists, orthodontists, and oral and maxillofacial surgeons as a treatment planning tool. Two of the more popular methods of analysis used in orthodontology are the Steiner analysis (named after Cecil C. Steiner) and the Downs analysis (named after William B. Downs). There are other methods as well which are listed below. Cephalometric radiographs Cephalometric analysis depends on cephalometric radiography to study relationships between bony and soft tissue landmarks and can be used to diagnose facial growth abnormalities prior to treatment, in the middle of treatment to evaluate progress, or at the conclusion of treatment to ascertain that the goals of treatment have been met. A Cephalometric radiograph is a radiograph of the head taken in a Cephalometer (Cephalostat) that is a head-holding device introduc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecanthus
Telecanthus, or dystopia canthorum, refers to increased distance between the inner corners of the eyelids (medial canthi), while the inter-pupillary distance is normal. This is in contrast to hypertelorism, in which the distance between the whole eyes is increased. Telecanthus and hypertelorism are each associated with multiple congenital disorders. The distance between the inner corners of the eyelids is called the intercanthal distance. In most people, the intercanthal distance is equal to the width of each eye (the distance between the inner and outer corners of each eye). The average interpupillary distance is 60–62 millimeters (mm), which corresponds to an intercanthal distance of approximately 30–31 mm. ''Traumatic telecanthus'' refers to telecanthus resulting from traumatic injury to the nasal- orbital-ethmoid (NOE) complex. The diagnosis of traumatic telecanthus requires a measurement in excess of those normative values. The pathology can be either unilateral or b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palpebral Fissure
The palpebral fissure is the elliptic space between the medial and lateral canthi of the two open eyelids. In simple terms, it is the opening between the eyelids. In adult humans, this measures about 10 mm vertically and 30 mm horizontally. Variations Congenital dysmorphisms It can be reduced (short, "narrow") in horizontal size by fetal alcohol syndrome and in Williams syndrome. The chromosomal conditions trisomy 9 and trisomy 21 (Down syndrome) can cause the palpebral fissures to be upslanted, whereas Marfan syndrome can cause a downslant. An increase in vertical height can be seen in genetic disorders such as cri-du-chat syndrome. Acquired The fissure may be increased in vertical height in Graves' disease, which is manifested as Dalrymple's sign. It is seen in disorders such as cri-du-chat syndrome. In animal studies using four times the therapeutic concentration of the ophthalmic solution latanoprost, the size of the palpebral fissure can be increased. The condit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commissure
A commissure () is the location at which two objects abut or are joined. The term is used especially in the fields of anatomy and biology. * The most common usage of the term refers to the brain's commissures, of which there are five. Such a commissure is a bundle of commissural fibers as a tract that crosses the midline at its level of origin or entry (as opposed to a decussation of fibers that cross obliquely). The five are the anterior commissure, posterior commissure, corpus callosum, commissure of fornix (hippocampal commissure), and habenular commissure. They consist of fibre tracts that connect the two cerebral hemispheres and span the longitudinal fissure. In the spinal cord there are the anterior white commissure, and the gray commissure. ''Commissural neurons'' refer to neuronal cells that grow their axons across the midline of the nervous system within the brain and the spinal cord. * ''Commissure'' also often refers to cardiac anatomy of heart valves. In the heart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waardenburg Syndrome
Waardenburg syndrome is a group of rare genetic conditions characterised by at least some degree of congenital hearing loss and pigmentation deficiencies, which can include bright blue eyes (or one blue eye and one brown eye), a white forelock or patches of light skin. These basic features constitute type 2 of the condition; in type 1, there is also a wider gap between the inner corners of the eyes called telecanthus, or dystopia canthorum. In type 3, which is rare, the arms and hands are also malformed, with permanent finger contractures or fused fingers, while in type 4, the person also has Hirschsprung's disease. There also exist at least two types (2E and PCWH) that can result in central nervous system (CNS) symptoms such as developmental delay and muscle tone abnormalities. The syndrome is caused by mutations in any of several genes that affect the division and migration of neural crest cells during embryonic development (though some of the genes involved also affect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commissure
A commissure () is the location at which two objects abut or are joined. The term is used especially in the fields of anatomy and biology. * The most common usage of the term refers to the brain's commissures, of which there are five. Such a commissure is a bundle of commissural fibers as a tract that crosses the midline at its level of origin or entry (as opposed to a decussation of fibers that cross obliquely). The five are the anterior commissure, posterior commissure, corpus callosum, commissure of fornix (hippocampal commissure), and habenular commissure. They consist of fibre tracts that connect the two cerebral hemispheres and span the longitudinal fissure. In the spinal cord there are the anterior white commissure, and the gray commissure. ''Commissural neurons'' refer to neuronal cells that grow their axons across the midline of the nervous system within the brain and the spinal cord. * ''Commissure'' also often refers to cardiac anatomy of heart valves. In the heart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Palpebral Raphe
The lateral palpebral raphe is a ligamentous band near the eye. Its existence is contentious, and many sources describe it as the continuation of nearby muscles. It is formed from the lateral ends of the orbicularis oculi muscle. It connects the orbicularis oculi muscle, the frontosphenoidal process of the zygomatic bone, and the tarsi of the eyelids. Structure The lateral palpebral raphe is formed from the lateral ends of the orbicularis oculi muscle. It may also be formed from the pretarsal muscles of the eyelids. It is attached to the margin of the frontosphenoidal process of the zygomatic bone. It passes towards the midline to the lateral commissure of the eyelids. Here, it divides into two slips, which are attached to the margins of the respective tarsi of the eyelids. The lateral palpebral ligament has a tensile strength of around 12 newtons. Relations The lateral palpebral raphe is a much weaker structure than the medial palpebral ligament on the other side ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
