|
Uncus
The uncus is an anterior extremity of the parahippocampal gyrus. It is separated from the apex of the temporal lobe by a sulcus called the 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 or ''tail'' of the dentate gyrus. The term comes from the Latin word uncus, meaning ''hook'', and it was coined by Félix Vicq-d'Azyr (1748–1794). 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: herniations and seizures * Herniations of the brain can occur if increased intracranial pressure due to a tumor, hemorrhage, or edema pushes the uncus over the tentorial notch against the brainstem and related cranial nerves. This can compress the oculomotor nerve (CN III). This causes pr ... [...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 human brain, brain 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 brain compartments. In such cases local pressure is increased at the place where the herniation occurs, but this pressure is not transmitted to the rest of the brain, and therefore does not register as an increase in ICP. Because herniation pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lepidoptera
Lepidoptera ( ) or lepidopterans is an order (biology), order of winged insects which includes butterflies and moths. About 180,000 species of the Lepidoptera have been described, representing 10% of the total described species of living organisms, making it the second largest insect order (behind Coleoptera) with 126 family (biology), families and 46 Taxonomic rank, superfamilies, and one of the most widespread and widely recognizable insect orders in the world. 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, large triangular Insect wing, wings, and a proboscis for siphoning nectars. The scales are modified, flattened "hairs", and give butterflies and moths their wide variety of colors and patterns. Almost all species have some form of membranous wings, except for a few that have reduced wings or are wingless. Mating and the laying of eggs is normally performe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edema
Edema (American English), also spelled oedema (British English), and also known as fluid retention, swelling, dropsy and hydropsy, is the build-up of fluid in the body's tissue (biology), tissue. Most commonly, the legs or arms are affected. Symptoms may include skin that feels tight, the area feeling heavy, and joint stiffness. Other symptoms depend on the underlying cause. Causes may include Chronic venous insufficiency, venous insufficiency, heart failure, kidney problems, hypoalbuminemia, low protein levels, liver problems, deep vein thrombosis, infections, kwashiorkor, angioedema, certain medications, and lymphedema. It may also occur in immobile patients (stroke, spinal cord injury, aging), or with temporary immobility such as 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 involve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seizures
A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, or consciousness. Symptoms vary widely. Some seizures involve subtle changes, such as brief lapses in attention or awareness (as seen in absence seizures), while others cause generalized convulsions with loss of consciousness ( tonic–clonic seizures). Most seizures last less than two minutes and are followed by a postictal period of confusion, fatigue, or other symptoms. A seizure lasting longer than five minutes is a medical emergency known as status epilepticus. Seizures are classified as provoked, when triggered by a known cause such as fever, head trauma, or metabolic imbalance, or unprovoked, when no immediate trigger is identified. Recurrent unprovoked seizures define the neurological condition epilepsy. Clinical features Seizur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amygdala
The amygdala (; : amygdalae or amygdalas; also '; Latin from Greek language, Greek, , ', 'almond', 'tonsil') is a paired nucleus (neuroanatomy), nuclear complex present in the Cerebral hemisphere, cerebral hemispheres of vertebrates. It is considered part of the limbic system. In Primate, primates, it is located lateral and medial, medially within the temporal lobes. It consists of many nuclei, each made up of further subnuclei. The subdivision most commonly made is into the Basolateral amygdala, basolateral, Central nucleus of the amygdala, central, cortical, and medial nuclei together with the intercalated cells of the amygdala, intercalated cell clusters. The amygdala has a primary role in the processing of memory, decision making, decision-making, and emotions, emotional responses (including fear, anxiety, and aggression). The amygdala was first identified and named by Karl Friedrich Burdach in 1822. Structure Thirteen Nucleus (neuroanatomy), nuclei have been identif ... [...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 w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemiparesis
Hemiparesis, also called unilateral paresis, is the weakness of one entire side of the body (''wikt:hemi-#Prefix, hemi-'' means "half"). Hemiplegia, in its most severe form, is the complete paralysis of one entire side of the body. Either hemiparesis or hemiplegia can result from a variety of medical causes, including congenital conditions, trauma, tumors, traumatic brain injury and stroke.Detailed article about hemiparesis at Disabled-World.com Signs and symptoms Different types of hemiparesis can impair different bodily functions. Some effects, such as weakness or partial paralysis of a limb on the affected side, are generally always to be expected. Other impairments can appear, upon external examination, to be unrelated to the limb weakness, but are nevertheless also cau ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 (In Latin, ''ped-'' means 'foot'.) 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) 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 (''crus'' means ‘leg’ in Latin.) or the pes pedunculi (''pes'' means 'foot' in Latin.). 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 cer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reticular Activating System
The reticular formation is a set of interconnected nuclei in the brainstem that spans from the lower end of the medulla oblongata to the upper end of the midbrain. The neurons of the reticular formation make up a complex set of neural networks in the core of the brainstem. The reticular formation is made up of a diffuse net-like formation of reticular nuclei which is not well-defined. It may be seen as being made up of all the interspersed cells in the brainstem between the more compact and named structures. The reticular formation is functionally divided into the ascending reticular activating system (ARAS), ascending pathways to the cerebral cortex, and the descending reticular system, descending pathways ( reticulospinal tracts) to the spinal cord. Due to its extent along the brainstem it may be divided into different areas such as the midbrain reticular formation, the central mesencephalic reticular formation, the pontine reticular formation, the paramedian pontine reticul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ipsilateral
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. 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 axes. The meaning of terms that are used can change depending on whether a vertebrate is a biped or a quadruped, due to the difference in the neuraxis, or if an invertebrate is a non-bilaterian. A non-bilaterian has no anterior or posterior surface for example but can still have a descriptor used such as proximal or distal in relation to a body part that is nearest to, or furthest from its middle. International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, '' Terminolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
