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Uncus
The uncus is an anterior extremity of the parahippocampal gyrus. It is separated from the apex of the temporal lobe by a slight fissure called the incisura temporalis (also called rhinal sulcus). Although superficially continuous with the hippocampal gyrus, the uncus forms morphologically a part of the rhinencephalon. An important landmark that crosses the inferior surface of the uncus is the band of Giacomini. The term comes from the Latin word uncus, meaning ''hook'', and it was coined by Félix Vicq-d'Azyr (1748–1794).JC Tamraz, YG Comair. Atlas of Regional Anatomy of the Brain Using MRI (2006), p 8. Clinical significance The part of the olfactory cortex that is on the temporal lobe covers the area of the uncus, which leads into the two significant clinical aspects of the uncus: uncinate fits and uncal herniations. * Seizures, often preceded by hallucinations of disagreeable odors, often originate in the uncus. * In situations of tumor, hemorrhage, or edema, incr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain Herniation
Brain herniation is a potentially deadly side effect of very high pressure within the skull that occurs when a part of the 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 ... is squeezed across structures within the human skull, skull. The brain can shift across such structures as the falx cerebri, the tentorium cerebelli, and even through the foramen magnum (the hole in the base of the skull through which the spinal cord connects with the brain). Herniation can be caused by a number of factors that cause a mass effect (medicine), mass effect and increase intracranial pressure (ICP): these include traumatic brain injury, intracranial hemorrhage, or brain tumor. Herniation can also occur in the absence of high ICP when mass lesions such as hematomas occur at the borders of brai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lepidoptera
Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic rank, superfamilies, 10 percent of the total described species of living organisms. It is one of the most widespread and widely recognizable insect orders in the world. The Lepidoptera show many variations of the basic body structure that have evolved to gain advantages in lifestyle and distribution. Recent estimates suggest the order may have more species than earlier thought, and is among the four most wikt:speciose, speciose orders, along with the Hymenoptera, fly, Diptera, and beetle, Coleoptera. Lepidopteran species are characterized by more than three derived features. The most apparent is the presence of scale (anatomy), scales that cover the torso, bodies, wings, and a proboscis. The scales are modified, flattened "hairs", and give ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edema
Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels tight, the area may feel heavy, and joint stiffness. Other symptoms depend on the underlying cause. Causes may include venous insufficiency, heart failure, kidney problems, low protein levels, liver problems, deep vein thrombosis, infections, angioedema, certain medications, and lymphedema. It may also occur after prolonged sitting or standing and during menstruation or pregnancy. The condition is more concerning if it starts suddenly, or pain or shortness of breath is present. Treatment depends on the underlying cause. If the underlying mechanism involves sodium retention, decreased salt intake and a diuretic may be used. Elevating the legs and support stockings may be useful for edema of the legs. Older people are more commonly affected. The wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decussate
Decussation is used in biological contexts to describe a crossing (due to the shape of the Roman numeral for ten, an uppercase 'X' (), ). In Latin anatomical terms, the form is used, e.g. . Similarly, the anatomical term chiasma is named after the Greek uppercase 'Χ' (chi). Whereas a decussation refers to a crossing within the central nervous system, various kinds of crossings in the peripheral nervous system are called chiasma. Examples include: * In the brain, where nerve fibers obliquely cross from one lateral side of the brain to the other, that is to say they cross at a level other than their origin. See for examples Decussation of pyramids and sensory decussation. In neuroanatomy, the term ''chiasma'' is reserved for crossing of- or within nerves such as in the optic chiasm. * In botanical leaf taxology, the word ''decussate'' describes an opposite pattern of leaves which has successive pairs at right angles to each other (i.e. rotated 90 degrees along the stem whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemiparesis
Hemiparesis, or unilateral paresis, is weakness of one entire side of the body ('' hemi-'' means "half"). Hemiplegia is, in its most severe form, complete paralysis of half of the body. Hemiparesis and hemiplegia can be caused by different medical conditions, including congenital causes, trauma, tumors, or stroke.Detailed article about hemiparesis at Disabled-World.com Signs and symptoms Depending on the type of hemiparesis diagnosed, different bodily functions can be affected. Some effects are expected (e.g., partial paralysis of a limb on the affected side). Other impairments, though, can at first seem completely non-related to the limb weakness but are, in fact, a direct result of the damage to the affected side of the brain. Loss of ...
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Kernohan's Notch
Kernohan's notch is a cerebral peduncle indentation associated with some forms of transtentorial herniation (uncal herniation). It is a secondary condition caused by a primary injury on the ''opposite'' hemisphere of the brain. Wolf et al, 1995 Kernohan's notch is an ipsilateral condition, in that a left-sided primary lesion (in which Kernohan's notch would be on the right side) evokes motor impairment in the left side of the body and a right-sided primary injury evokes motor impairment in the right side of the body. Pearce, 2006 The seriousness of Kernohan's notch varies depending on the primary problem causing it, which may range from benign brain tumors to advanced subdural hematoma. Mechanism Kernohan's notch phenomenon is a result of the compression of the cerebral peduncle, which is part of the mesencephalon, against the tentorium cerebelli due to transtentorial herniation. This produces ipsilateral hemiparesis or hemiplegia The skull is an incompressible closed space with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebral Peduncle
The cerebral peduncles are the two stalks that attach the cerebrum to the brainstem. They are structures at the front of the midbrain which arise from the ventral pons and contain the large ascending (sensory) and descending (motor) nerve tracts that run to and from the cerebrum from the pons. Mainly, the three common areas that give rise to the cerebral peduncles are the cerebral cortex, the spinal cord and the cerebellum. The region includes the tegmentum, crus cerebri and pretectum. By this definition, the cerebral peduncles are also known as the basis pedunculi, while the large ventral bundle of efferent fibers is referred to as the cerebral crus or the pes pedunculi. The cerebral peduncles are located on either side of the midbrain and are the frontmost part of the midbrain, and act as the connectors between the rest of the midbrain and the thalamic nuclei and thus the cerebrum. As a whole, the cerebral peduncles assist in refining motor movements, learning new motor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reticular Activating System
The reticular formation is a set of interconnected nuclei that are located throughout the brainstem. It is not anatomically well defined, because it includes neurons located in different parts of the brain. The neurons of the reticular formation make up a complex set of networks in the core of the brainstem that extend from the upper part of the midbrain to the lower part of the medulla oblongata. The reticular formation includes ascending pathways to the cortex in the ascending reticular activating system (ARAS) and descending pathways to the spinal cord via the reticulospinal tracts. Neurons of the reticular formation, particularly those of the ascending reticular activating system, play a crucial role in maintaining behavioral arousal and consciousness. The overall functions of the reticular formation are modulatory and premotor, involving somatic motor control, cardiovascular control, pain modulation, sleep and consciousness, and habituation. The modulatory functions are pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ipsilateral
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabularies for subdisciplines of anatom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cranial Nerve III
The oculomotor nerve, also known as the third cranial nerve, cranial nerve III, or simply CN III, is a cranial nerve that enters the orbit through the superior orbital fissure and innervates extraocular muscles that enable most movements of the eye and that raise the eyelid. The nerve also contains fibers that innervate the intrinsic eye muscles that enable pupillary constriction and accommodation (ability to focus on near objects as in reading). The oculomotor nerve is derived from the basal plate of the embryonic midbrain. Cranial nerves IV and VI also participate in control of eye movement. Structure The oculomotor nerve originates from the third nerve nucleus at the level of the superior colliculus in the midbrain. The third nerve nucleus is located ventral to the cerebral aqueduct, on the pre-aqueductal grey matter. The fibers from the two third nerve nuclei located laterally on either side of the cerebral aqueduct then pass through the red nucleus. From the red nuc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cranial Nerves
Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), of which there are conventionally considered twelve pairs. Cranial nerves relay information between the brain and parts of the body, primarily to and from regions of the head and neck, including the special senses of vision, taste, smell, and hearing. The cranial nerves emerge from the central nervous system above the level of the first vertebra of the vertebral column. Each cranial nerve is paired and is present on both sides. There are conventionally twelve pairs of cranial nerves, which are described with Roman numerals I–XII. Some considered there to be thirteen pairs of cranial nerves, including cranial nerve zero. The numbering of the cranial nerves is based on the order in which they emerge from the brain and brainstem, from front to back. The terminal nerves (0), olfactory nerves (I) and optic nerves (II) emerge from the cerebrum, and the remaining ten pairs arise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
