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Anotia Bonnetii
Anotia ("no ear") describes a rare congenital deformity that involves the complete absence of the pinna, the outer projected portion of the ear, and narrowing or absence of the ear canal. This contrasts with microtia, in which a small part of the pinna is present. Anotia and microtia may occur unilaterally (only one ear affected) or bilaterally (both ears affected). This deformity results in conductive hearing loss, deafness. Ear development Ear development begins in about the third week of human embryonic development, beginning with the formation of the Otic Placodes, an extension of the early hind brain. By the fourth week of development the otic placodes invaginate, or sink inward forming pits which close themselves off for the outer surface ectoderm and begin forming the inner ear labyrinthe on the inside. Outer ear development begins in about the fifth week of human embryonic development. Upon the pharyngeal arches Auricle Hillocks begin to form. By the seventh week the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congenital Disorder
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can range from mild to severe. Birth defects are divided into two main types: structural disorders in which problems are seen with the shape of a body part and functional disorders in which problems exist with how a body part works. Functional disorders include metabolic and degenerative disorders. Some birth defects include both structural and functional disorders. Birth defects may result from genetic or chromosomal disorders, exposure to certain medications or chemicals, or certain infections during pregnancy. Risk factors include folate deficiency, drinking alcohol or smoking during pregnancy, poorly controlled diabetes, and a mother over the age of 35 years old. Many are believed to involve multiple factors. Birth defects may b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinna (anatomy)
The auricle or auricula is the visible part of the ear that is outside the head. It is also called the pinna (Latin for " wing" or " fin", plural pinnae), a term that is used more in zoology. Structure The diagram shows the shape and location of most of these components: * '' antihelix'' forms a 'Y' shape where the upper parts are: ** ''Superior crus'' (to the left of the ''fossa triangularis'' in the diagram) ** ''Inferior crus'' (to the right of the ''fossa triangularis'' in the diagram) * '' Antitragus'' is below the ''tragus'' * ''Aperture'' is the entrance to the ear canal * ''Auricular sulcus'' is the depression behind the ear next to the head * ''Concha'' is the hollow next to the ear canal * Conchal angle is the angle that the back of the ''concha'' makes with the side of the head * ''Crus'' of the helix is just above the ''tragus'' * ''Cymba conchae'' is the narrowest end of the ''concha'' * External auditory meatus is the ear canal * ''Fossa triangularis'' is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goldenhar Syndrome
Goldenhar syndrome is a rare congenital defect characterized by incomplete development of the ear, nose, soft palate, lip and mandible on usually one side of the body. Common clinical manifestations include limbal dermoids, preauricular skin tags and strabismus. It is associated with anomalous development of the first branchial arch and second branchial arch. The term is sometimes used interchangeably with hemifacial microsomia, although this definition is usually reserved for cases without internal organ and vertebrae disruption. It affects between 1 in 3,500 and 1 in 5,600 live births, with a male-to-female ratio of 3:2. Signs and symptoms Chief markers of Goldenhar syndrome are incomplete development of the ear, nose, soft palate, lip, and mandible on usually one side of the body. Additionally, some patients will have growing issues with internal organs, especially heart, kidneys and lungs. Typically, the organ will either not be present on one side or will be underdevel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone Anchored Hearing Aid
A bone-anchored hearing aid (BAHA) is a type of hearing aid based on bone conduction. It is primarily suited for people who have conductive hearing losses, unilateral hearing loss, single-sided deafness and people with mixed hearing losses who cannot otherwise wear 'in the ear' or 'behind the ear' hearing aids. They are more expensive than conventional hearing aids, and their placement involves invasive surgery which carries a risk of complications, although when complications do occur, they are usually minor. Two of the causes of hearing loss are lack of function in the inner ear (cochlea) and when the sound has problems in reaching the nerve cells of the inner ear. Examples of the first include age-related hearing loss and hearing loss due to noise exposure. A patient born without external ear canals is an example of the latter for which a conventional hearing aid with a mould in the ear canal opening would not be effective. Some with this condition have normal inner ear funct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treacher-Collins Syndrome
Treacher Collins syndrome (TCS) is a genetic disorder characterized by deformities of the ears, eyes, cheekbones, and chin. The degree to which a person is affected, however, may vary from mild to severe. Complications may include breathing problems, problems seeing, cleft palate, and hearing loss. Those affected generally have normal intelligence. TCS is usually autosomal dominant. More than half the time it occurs as a result of a new mutation rather than being inherited from a person's parents. The involved genes may include '' TCOF1'', ''POLR1C'', or '' POLR1D''. Diagnosis is generally suspected based on symptoms and X-rays, and potentially confirmation by genetic testing. Treacher Collins syndrome is not curable. Symptoms may be managed with reconstructive surgery, hearing aids, speech therapy, and other assistive devices. Life expectancy is generally normal. TCS occurs in about one in 50,000 people. The syndrome is named after Edward Treacher Collins, an English surgeo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain
The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head ( cephalization), usually near organs for special senses such as vision, hearing and olfaction. Being the most specialized organ, it is responsible for receiving information from the sensory nervous system, processing those information (thought, cognition, and intelligence) and the coordination of motor control (muscle activity and endocrine system). While invertebrate brains arise from paired segmental ganglia (each of which is only responsible for the respective body segment) of the ventral nerve cord, vertebrate brains develop axially from the midline dorsal nerve cord as a vesicular enlargement at the rostral end of the neural tube, with centralized control over all body segments. All vertebrate brains can be embryonically divided into three parts: the forebrain (prosencep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auditory Nerve
The cochlear nerve (also auditory nerve or acoustic nerve) is one of two parts of the vestibulocochlear nerve, a cranial nerve present in amniotes, the other part being the vestibular nerve. The cochlear nerve carries auditory sensory information from the cochlea of the inner ear directly to the brain. The other portion of the vestibulocochlear nerve is the vestibular nerve, which carries spatial orientation information to the brain from the semicircular canals, also known as semicircular ducts. Anatomy and connections In terms of anatomy, an auditory nerve fiber is either bipolar or unipolar, with its distal projection being called the peripheral process, and its proximal projection being called the axon; these two projections are also known as the "peripheral axon" and the "central axon", respectively. The peripheral process is sometimes referred to as a dendrite, although that term is somewhat inaccurate. Unlike the typical dendrite, the peripheral process generates and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tympanic Membrane
In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit sound from the air to the ossicles inside the middle ear, and then to the oval window in the fluid-filled cochlea. Hence, it ultimately converts and amplifies vibration in the air to vibration in cochlear fluid. The malleus bone bridges the gap between the eardrum and the other ossicles. Rupture or perforation of the eardrum can lead to conductive hearing loss. Collapse or retraction of the eardrum can cause conductive hearing loss or cholesteatoma. Structure Orientation and relations The tympanic membrane is oriented obliquely in the anteroposterior, mediolateral, and superoinferior planes. Consequently, its superoposterior end lies lateral to its anteroinferior end. Anatomically, it relates superiorly to the middle cranial fossa, posteriorly to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pharyngeal Arches
The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development of vertebrates that are recognisable precursors for many structures. In fish, the arches are known as the branchial arches, or gill arches. In the human embryo, the arches are first seen during the fourth week of development. They appear as a series of outpouchings of mesoderm on both sides of the developing pharynx. The vasculature of the pharyngeal arches is known as the aortic arches. In fish, the branchial arches support the gills. Structure In vertebrates, the pharyngeal arches are derived from all three germ layers (the primary layers of cells that form during embryogenesis). Neural crest cells enter these arches where they contribute to features of the skull and facial skeleton such as bone and cartilage. However, the existence of pharyngeal structures before neural crest cells evolved is indicated by the existence of neural crest-independent mechanisms of phar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deformity
A deformity, dysmorphism, or dysmorphic feature is a major abnormality of an organism that makes a part of the body appear or function differently than how it is supposed to. Causes Deformity can be caused by a variety of factors: *Arthritis and other rheumatoid disorders *Chronic application of external forces, e.g. artificial cranial deformation *Chronic paresis, paralysis or muscle imbalance, especially in children, e.g. due to poliomyelitis or cerebral palsy *Complications at birth *Damage to the fetus or uterus *Fractured bones left to heal without being properly set (malunion) *Genetic mutation *Growth or hormone disorders *Infection *Reconstructive surgery following a severe injury, e.g. burn injury Deformity can occur in all organisms: * Frogs can be mutated due to Ribeiroia (Trematoda) infection. * Plants can undergo irreversible cell deformation * Insects, such as honeybees, can be affected by deformed wing virus * Fish can be found with scoliosis due to enviro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectoderm
The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from the outer layer of germ cells. The word ectoderm comes from the Greek ''ektos'' meaning "outside", and ''derma'' meaning "skin".Gilbert, Scott F. Developmental Biology. 9th ed. Sunderland, MA: Sinauer Associates, 2010: 333-370. Print. Generally speaking, the ectoderm differentiates to form epithelial and neural tissues ( spinal cord, peripheral nerves and brain). This includes the skin, linings of the mouth, anus, nostrils, sweat glands, hair and nails, and tooth enamel. Other types of epithelium are derived from the endoderm. In vertebrate embryos, the ectoderm can be divided into two parts: the dorsal surface ectoderm also known as the external ectoderm, and the neural plate, which invaginates to form the neural tube and neural c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deprivation Imbecile A
Deprivation or deprive may refer to: * Poverty, pronounced deprivation in well-being ** Objective deprivation or poverty threshold, the minimum level of income deemed adequate in a particular country ** Relative deprivation, the lack of resources to sustain the lifestyle that one is accustomed to or that a society approves * Deprivation (child development), inadequate meeting of child's needs required for an adequate child development * Deprivation of rights under color of law, a federal criminal offense under U.S. law * Deprivation, the taking away from a clergyman of his benefice or other spiritual promotion or dignity by an ecclesiastical court See also * * Forfeiture (law), deprivation of a right in consequence of the non-performance of some obligation * Hypoxia (medical), a medical condition where the body is deprived of adequate oxygen supply at the tissue level * Child neglect A form of child abuse, child neglect is an act of caregivers (e.g., parents) that results in d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
