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Tragus (anatomy)
The tragus is a small pointed eminence of the external ear, situated in front of the concha, and projecting backward over the meatus. It also is the name of hair growing at the entrance of the ear. Its name comes the Ancient Greek (), meaning 'goat', and is descriptive of its general covering on its under surface with a tuft of hair, resembling a goat's beard. The nearby antitragus projects forwards and upwards. Because the tragus faces rearwards, it aids in collecting sounds from behind. These sounds are delayed more than sounds arriving from the front, assisting the brain to sense front vs. rear sound sources. In a positive fistula test (for the presence of a fistula from cholesteatoma to the labyrinth), pressure on the tragus causes vertigo or eye deviation by inducing movement of perilymph. Other animals The tragus is a key feature in many bat species. As a piece of skin in front of the ear canal, it plays an important role in directing sounds into the ear for prey locatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
External Ear
The outer ear, external ear, or auris externa is the external part of the ear, which consists of the auricle (also pinna) and the ear canal. It gathers sound energy and focuses it on the eardrum (tympanic membrane). Structure Auricle The visible part is called the auricle, also known as the pinna, especially in other animals. It is composed of a thin plate of yellow elastic cartilage, covered with integument, and connected to the surrounding parts by ligaments and muscles; and to the commencement of the ear canal by fibrous tissue. Many mammals can move the pinna (with the auriculares muscles) in order to focus their hearing in a certain direction in much the same way that they can turn their eyes. Most humans do not have this ability. Ear canal From the pinna, the sound waves move into the ear canal (also known as the ''external acoustic meatus'') a simple tube running through to the middle ear. This tube leads inward from the bottom of the auricula and conduct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inner Ear
The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts: * The cochlea, dedicated to hearing; converting sound pressure patterns from the outer ear into electrochemical impulses which are passed on to the brain via the auditory nerve. * The vestibular system, dedicated to balance The inner ear is found in all vertebrates, with substantial variations in form and function. The inner ear is innervated by the eighth cranial nerve in all vertebrates. Structure The labyrinth can be divided by layer or by region. Bony and membranous labyrinths The bony labyrinth, or osseous labyrinth, is the network of passages with bony walls lined with periosteum. The three major parts of the bony labyrinth are the vestib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tragal Pressure
Tragal pressure is pressure that is applied to the cartilage at the front, or anterior aspect of the ear canal (called the tragus), closing the canal and increasing pressure on the tympanic membrane (ear drum). Tragal pumping is the act of repeatedly applying tragal pressure in quick succession to help deliver ear drop Ear drops are a form of topical medication for the ears used to treat otitis, infection, inflammation, Earwax#Excess earwax (impacted cerumen), impacted ear wax and local anesthesia. They are commonly used for short-term treatment and can be pur ...s deeper into the ear canal. References {{Reflist Ear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auricular Branch Of The Vagus Nerve
The auricular branch of the vagus nerve is often termed the Alderman's nerve or Arnold's nerve. The latter name is an eponym for Friedrich Arnold. The auricular branch of the vagus nerve supplies sensory innervation to the skin of the ear canal, tragus, and auricle. Path It arises from the superior ganglion of the vagus nerve, and is joined soon after its origin by a filament from the petrous ganglion of the glossopharyngeal; it passes behind the internal jugular vein, and enters the mastoid canaliculus on the lateral wall of the jugular fossa. Traversing the substance of the temporal bone, it crosses the facial canal about above the stylomastoid foramen, and here it gives off an ascending branch which joins the facial nerve. The nerve reaches the surface by passing through the tympanomastoid fissure between the mastoid process and the tympanic part of the temporal bone, and divides into two branches: * one joins the posterior auricular nerve. * the other is distributed to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spotted Bat
The spotted bat (''Euderma maculatum'') is a species of vesper bat and the only species of the genus ''Euderma''. Description The spotted bat was first described by zoologist Joel Asaph Allen from the American Museum of Natural History in 1891. It can reach a length of 12 cm and a wingspan of 35 cm. The weight is about 15 g. It has three distinctive white spots on its black back. With ears that can grow up to 4 cm, it is said to have the largest ears of any bat species in North America. The spotted bat's mating season is in autumn and the females produce their offspring (usually one juvenile) in June or July. Its main diet is grasshoppers and moths. Habitat The habitats of the spotted bat are undisturbed roosts on cliffs along the Grand Canyon in Arizona, and open and dense deciduous and coniferous forests, hay fields, deserts, marshes, riparian areas, and dry shrub-steppe grasslands in Arizona, California, Colorado, Oregon, New Mexico, Utah, Washington, and Briti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eastern Red Bat
The eastern red bat (''Lasiurus borealis'') is a species of microbat in the family Vespertilionidae. Eastern red bats are widespread across eastern North America, with additional records in Bermuda. Taxonomy and etymology It was described in 1776 by German zoologist Philipp Ludwig Statius Müller. He initially placed it in the genus ''Vespertilio'', with the name ''Vespertilio borealis''. It was not placed into its current genus '' Lasiurus'' until the creation of the genus in 1831 by John Edward Gray. The generic name "''Lasiurus''" is derived from the Greek '' lasios'' ("hairy") and '' oura'' ("tail"); its species name "''borealis''" is Latin in origin, meaning "northern." Of the species in its genus, the eastern red bat is most closely related to other red bats, with which they form a monophyly. Its closest relatives are the Pfeiffer's red bat (''Lasiurus pfeifferi''), Seminole bat (''L. seminolus''), cinnamon red bat (''L. varius''), desert red bat (''L. blossevillii''), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Long-eared Bat
The brown long-eared bat or common long-eared bat (''Plecotus auritus'') is a small Eurasian insectivorous bat. It has distinctive ears, long and with a distinctive fold. It is extremely similar to the much rarer grey long-eared bat which was only validated as a distinct species in the 1960s. An adult brown long-eared bat has a body length of 4.5–4.8 cm, a tail of 4.1–4.6 cm, and a forearm length of 4–4.2 cm. The ears are 3.3–3.9 cm in length, and readily distinguish the long-eared bats from most other bat species. They are relatively slow flyers compared to other bat species. Habitat The brown long-eared bat is found throughout Europe, with the exception of Greece, southern Italy and southern Spain. It is found to the east up to the Urals and Caucasus. The UK distribution can be found on the National Biodiversity Network website and can be seehere Brown long-eared bats regularly utilise buildings roosting in undisturbed roof spaces either singly, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horseshoe Bat
Horseshoe bats are bats in the family Rhinolophidae. In addition to the single living genus, ''Rhinolophus'', which has about 106 species, the extinct genus '' Palaeonycteris'' has been recognized. Horseshoe bats are closely related to the Old World leaf-nosed bats, family Hipposideridae, which have sometimes been included in Rhinolophidae. The horseshoe bats are divided into six subgenera and many species groups. The most recent common ancestor of all horseshoe bats lived 34–40 million years ago, though it is unclear where the geographic roots of the family are, and attempts to determine its biogeography have been indecisive. Their taxonomy is complex, as genetic evidence shows the likely existence of many cryptic species, as well as species recognized as distinct that may have little genetic divergence from previously recognized taxa. They are found in the Old World, mostly in tropical or subtropical areas, including Africa, Asia, Europe, and Oceania. Horseshoe bats are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Echolocation
Echolocation, also called bio sonar, is a biological sonar used by several animal species. Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects. Echolocation is used for navigation, foraging, and hunting in various environments. Echolocating animals include some mammals (most notably Laurasiatheria) and a few birds, especially some bat species and odontocetes (toothed whales and dolphins), but also in simpler forms in other groups such as shrews, and two cave-dwelling bird groups, the so-called cave swiftlets in the genus ''Aerodramus'' (formerly ''Collocalia'') and the unrelated oilbird ''Steatornis caripensis''. Early research The term ''echolocation'' was coined in 1938 by the American zoologist Donald Griffin, who, with Robert Galambos, first demonstrated the phenomenon in bats. As Griffin described in his book, the 18th century I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perilymph
Perilymph is an extracellular fluid located within the inner ear. It is found within the scala tympani and scala vestibuli of the cochlea. The ionic composition of perilymph is comparable to that of plasma and cerebrospinal fluid. The major cation in perilymph is sodium, with the values of sodium and potassium concentration in the perilymph being 138 mM and 6.9 mM, respectively. It is also named Cotunnius' liquid and liquor cotunnii for Domenico Cotugno. Structure The inner ear has two major parts, the cochlea and the vestibular organ. They are connected in a series of canals in the temporal bone referred to as the bony labyrinth. The bone canals are separated by the membranes in parallel spaces referred to as the membranous labyrinth. The membranous labyrinth contains endolymph, and is surrounded by perilymph. The perilymph in the bony labyrinth serves as connection to the cerebrospinal fluid of the subarachnoid space via the perilymphatic duct. Composition Peri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertigo
Vertigo is a condition where a person has the sensation of movement or of surrounding objects moving when they are not. Often it feels like a spinning or swaying movement. This may be associated with nausea, vomiting, sweating, or difficulties walking. It is typically worse when the head is moved. Vertigo is the most common type of dizziness. The most common disorders that result in vertigo are benign paroxysmal positional vertigo (BPPV), Ménière's disease, and labyrinthitis. Less common causes include stroke, brain tumors, brain injury, multiple sclerosis, migraines, trauma, and uneven pressures between the middle ears. Physiologic vertigo may occur following being exposed to motion for a prolonged period such as when on a ship or simply following spinning with the eyes closed. Other causes may include toxin exposures such as to carbon monoxide, alcohol, or aspirin. Vertigo typically indicates a problem in a part of the vestibular system. Other causes of dizziness incl ... [...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 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 disruption, tinnitu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
