|
Ear Canal
The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the auricle to the eardrum and is about in length and in diameter. Structure The human ear canal is divided into two parts. The elastic cartilage part forms the outer third of the canal; its anterior and lower wall are cartilaginous, whereas its superior and back wall are fibrous. The cartilage is the continuation of the cartilage framework of auricle. The cartilaginous portion of the ear canal contains small hairs and specialized sweat glands, called apocrine glands, which produce cerumen ( ear wax). The bony part forms the inner two thirds. The bony part is much shorter in children and is only a ring (''annulus tympanicus'') in the newborn. The layer of epithelium encompassing the bony portion of the ear canal is much thinner and therefore, more sensitive in comparison to the cartilaginous portion. Size ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First Branchial Arch
The pharyngeal arches, also known as visceral arches'','' are transient structures seen in the Animal embryonic development, embryonic development of humans and other vertebrates, that are recognisable precursors for many structures. In fish, the arches support the Fish gill, gills and are known as the branchial arches, or gill arches. In the human embryo, the arches are first seen during the fourth week of human embryonic development, development. They appear as a series of outpouchings of mesoderm on both sides of the developing pharynx. The vasculature of the pharyngeal arches are the aortic arches that arise from the aortic sac. Structure In humans and other vertebrates, the pharyngeal arches are derived from all three germ layers (the primary layers of cells that form during embryonic development). 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 structu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigmoid , similar shape, term sometimes used for sigmoids
{{disambiguation ...
Sigmoid means resembling the lower-case Greek letter sigma (uppercase Σ, lowercase σ, lowercase in word-final position ς) or the Latin letter S. Specific uses include: * Sigmoid function, a mathematical function * Sigmoid colon, part of the large intestine or colon * Sigmoid sinus, two structures that drain blood from the bottom of the brain * Sigmoid arteries, a pair/trio of arteries in the lower abdomen See also * Ogee An ogee ( ) is an object, element, or curve—often seen in architecture and building trades—that has a serpentine- or extended S-shape (Sigmoid curve, sigmoid). Ogees consist of a "double curve", the combination of two semicircle, semicircula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stenosis
Stenosis () is the abnormal narrowing of a blood vessel or other tubular organ or structure such as foramina and canals. It is also sometimes called a stricture (as in urethral stricture). ''Stricture'' as a term is usually used when narrowing is caused by contraction of smooth muscle (e.g. achalasia, prinzmetal angina); ''stenosis'' is usually used when narrowing is caused by lesion that reduces the space of lumen (e.g. atherosclerosis). The term coarctation is another synonym, but is commonly used only in the context of aortic coarctation. Restenosis is the recurrence of stenosis after a procedure. Examples Examples of vascular stenotic lesions include: * Intermittent claudication (peripheral artery stenosis) * Angina ( coronary artery stenosis) * Carotid artery stenosis which predispose to (strokes and transient ischaemic episodes) * Renal artery stenosis Types In heart valves The types of stenoses in heart valves are: * Pulmonary valve stenosis, which is th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otitis Externa
Otitis externa, also called swimmer's ear, is inflammation of the ear canal. It often presents with ear pain, swelling of the ear canal, and occasionally decreased hearing. Typically there is pain with movement of the outer ear. A high fever is typically not present except in severe cases. Otitis externa may be acute (lasting less than six weeks) or chronic (lasting more than three months). Acute cases are typically due to bacterial infection, and chronic cases are often due to allergies and autoimmune disorders. The most common cause of otitis externa is bacterial. Risk factors for acute cases include swimming, minor trauma from cleaning, using hearing aids and ear plugs, and other skin problems, such as psoriasis and dermatitis. People with diabetes are at risk of a severe form of ''malignant otitis externa''. Diagnosis is based on the signs and symptoms. Culturing the ear canal may be useful in chronic or severe cases. Acetic acid ear drops may be used as a preventive m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tympanostomy Tube
Tympanostomy tube, also known as a grommet, myringotomy tube, or pressure equalizing tube, is a small tube inserted into the eardrum via a surgical procedure called myringotomy to keep the middle ear aerated for a prolonged period of time, typically to prevent accumulation of fluid in the middle ear. The tube itself is made in a variety of designs, most often shaped like a grommet for short-term use, or with long flanges and sometimes resembling a T-shape for long-term use. Materials used to manufacture the tubes are often made from fluoroplastic or silicone, which have largely replaced the use of metal tubes made from stainless steel, titanium, or gold. Medical uses Inserting tympanostomy tubes is one of the most common pediatric surgical procedures in the United States, with 9% of children having had tubes placed sometime in their lives. Tympanostomy tubes are typically placed in one or both eardrums to help children suffering from recurrent acute otitis media (ear infec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scar
A scar (or scar tissue) is an area of fibrosis, fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other Organ (anatomy), organs, and biological tissue, tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound (e.g., after accident, disease, or surgery) results in some degree of scarring. An exception to this are animals with complete Regeneration (biology), regeneration, which regrow tissue without scar formation. Scar tissue is composed of the same protein (collagen) as the tissue that it replaces, but the fiber composition of the protein is different; instead of a random basketweave formation of the collagen fibers found in normal tissue, in fibrosis the collagen cross-links and forms a pronounced alignment in a single direction. This collagen scar tissue alignment is usually of inferior functional quality to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granuloma
A granuloma is an aggregation of macrophages (along with other cells) that forms in response to chronic inflammation. This occurs when the immune system attempts to isolate foreign substances that it is otherwise unable to eliminate. Such substances include infectious organisms including bacteria and fungi, as well as other materials such as foreign objects, keratin, and suture fragments. Definition In pathology, a granuloma is an organized collection of macrophages. In medical practice, doctors occasionally use the term ''granuloma'' in its more literal meaning: "a small nodule". Since a small nodule can represent any tissue from a harmless nevus to a malignant tumor, this use of the term is not very specific. Examples of this use of the term ''granuloma'' are the lesions known as vocal cord granuloma (known as contact granuloma), pyogenic granuloma, and intubation granuloma, all of which are examples of granulation tissue, not granulomas. "Pulmonary hyalinizing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myiasis
Myiasis ( ), also known as flystrike or fly strike, is the parasitic infestation of the body of a live animal by fly larvae (maggots) that grow inside the host while feeding on its Biological tissue, tissue. Although flies are most commonly attracted to open wounds and urine- or feces-soaked fur, some species (including the most common myiatic flies—the botfly, Calliphoridae, blowfly, and Cochliomyia hominivorax, screwfly) can create an infestation even on unbroken skin. Non-myiatic flies (such as the common housefly) can be responsible for accidental myiasis. Because some animals (particularly non-native domestic animals) cannot react as effectively as humans to the causes and effects of myiasis, Parasitic flies of domestic animals, such infestations present a severe and continuing problem for livestock industries worldwide, causing severe economic losses where they are not mitigated by human action. Although typically a far greater issue for animals, myiasis is also a relativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ear Mite
Ear mites are mites that live in the ears of animals. The most commonly seen species in veterinary medicine is '' Otodectes cynotis'' (Gk. ''oto''=ear, ''dectes''=biter, ''cynotis''=of the dog). This species, despite its name, is also responsible for 90% of ear mite infections in felines. In veterinary practice, ear mite infections in dogs and cats may present as a disease that causes intense itching in one or both ears, which in turn triggers scratching at the affected ear. An unusually dark colored ear wax (cerumen) may also be produced. Cats, as well as dogs with erect ears that have control over ear direction, may be seen with one or both ear pinnas held at an odd or flattened angle. The most common lesion associated with ear mites is an open or crusted ("scabbed") skin wound at the back or base of the ear, caused by abrasion of the skin by hind limb claws, as the ear has been scratched in an attempt to relieve the itching. This lesion often becomes secondarily infected and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otomycosis
Otomycosis is a fungal ear infection, a superficial mycotic infection of the outer ear canal caused by micro-organisms called fungi which are related to yeast and mushrooms. It is more common in tropical or warm countries. The infection may be either subacute or acute and is characterized by itching in the ear, malodorous discharge, inflammation, pruritus, scaling, and severe discomfort or ear pain. The mycosis results in inflammation, superficial epithelial exfoliation, masses of debris containing hyphae, suppuration, and pain. Otomycosis can also cause hearing loss. Signs and symptoms Otomycosis does not usually cause as much canal skin edema as does acute bacterial external otitis. While a severe pressure type of pain is a prominent feature of advanced cases, the ear is usually much less tender, if at all, to traction or tragal pressure. Appearance of the fungus is variable, most commonly gray, white, or black, often intermixed with cerumen and clinging to the can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contact Dermatitis
Contact dermatitis is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents. Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes are not contagious or life-threatening, but can be very uncomfortable. Contact dermatitis results from either exposure to allergens ( allergic contact dermatitis), or irritants ( irritant contact dermatitis). Allergic contact dermatitis involves a delayed type of hypersensitivity and previous exposure to an allergen to produce a reaction. Irritant contact dermatitis is the most common type and represents 80% of all cases. It is caused by prolonged exposure to irritants, leading to direct injury of the epidermal cells of the skin, which activates an immune response, resulting in an inflammatory cutaneous reaction. Phototoxic dermatitis occurs when the allergen or irritant is activated by sunlight. Diagnosis of allergic contact dermati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholesteatoma
Cholesteatoma is a destructive and expanding growth consisting of keratinizing squamous epithelium in the middle ear and/or mastoid process. Cholesteatomas are not cancerous as the name may suggest, but can cause significant problems because of their erosive and expansile properties. This can result in the destruction of the bones of the middle ear (ossicles), as well as growth through the base of skull, base of the skull into the brain. They often become infected and can result in chronically draining ears. Treatment almost always consists of surgical removal. Signs and symptoms Other more common conditions (e.g. otitis externa) may also present with these symptoms, but cholesteatoma is much more serious and should not be overlooked. If a patient presents to a doctor with ear discharge and hearing loss, the doctor should consider cholesteatoma until the disease is definitely excluded. Other less common symptoms (all less than 15%) of cholesteatoma may include pain, balance disorde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
