The circle of Willis (circulus arteriosus cerebri) is an collection of arteries that are located at the base of the brain. The “circle” was named after Thomas Willis (1621-1675) by his student, Richard Lower. Willis authored Cerebri Anatome which described and depicted this vascular ring of arteries. The circle of Willis encircles the stalk of the pituitary gland and provides a connection between the internal carotid (the internal carotid is cut in this image) and the vertebrobasilar arterial brain supply systems. The circle of Willis is formed when each internal carotid artery divides into the anterior cerebral artery and middle cerebral artery. The anterior cerebral arteries are then united by an anterior communicating artery. Posteriorly, the basilar artery branches into a left and right posterior cerebral artery, forming the posterior circulation. The circle of Willis is completed by the posterior communicating arteries which join the posterior and internal carotid arteries. This arrangement potentially allows blood supply to the brain when there is occlusion of one of the internal carotid arteries, or vertebral arteries. However, the collateral circulation provided by this circle is typically insufficient to fully compensate for such an occlusion.
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hey connections #snsinstitutions #snsdesignthinkers #snsdesignthinking Muscle is a soft tissue, one of the four basic types of animal tissue. Muscle tissue gives skeletal muscles the ability to contract. Muscle is formed during embryonic development, in a process known as myogenesis. Muscle tissue contains special contractile proteins called actin and myosin which interact to cause movement. Among many other muscle proteins present are two regulatory proteins, troponin and tropomyosin Muscle tissue varies with function and location in the body. In vertebrates the three types are: skeletal or striated; smooth muscle (non-striated) muscle; and cardiac muscle.[1] Skeletal muscle tissue consists of elongated, multinucleate muscle cells called muscle fibers, and is responsible for movements of the body. Other tissues in skeletal muscle include tendons and perimysium.[citation needed] Smooth and cardiac muscle contract involuntarily, without conscious intervention. These muscle types may be activated both through the interaction of the central nervous system as well as by receiving innervation from peripheral plexus or endocrine (hormonal) activation. Striated or skeletal muscle only contracts voluntarily, upon the influence of the central nervous system. Reflexes are a form of non-conscious activation of skeletal muscles, but nonetheless arise through activation of the central nervous system, albeit not engaging cortical structures until after the contraction has occurred.
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Ophthopedia Update:Association of lesion location and functional parameters on vision-related quality of life in geographic atrophy secondary to AMD: The primary goal of this study was to determine how structural and functional parameters influence the vision-related quality of life (VRQoL) in patients suffering from geographic atrophy (GA) secondary to age-related macular degeneration. #Ophthalmology #Retina #Ophthotwitter
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OSTEOPATA D.O. - Medicina Osteopatica - Naprapatia - Esperto Nutrizione Funzionale
🔈 VAGUS NERVE DISTRIBUTION The vagus nerve (CN X) has the longest course and most extensive distribution of all the cranial nerves, most of which is outside of (inferior to) the head. The term vagus is derived from the Latin word vagary, meaning “wandering.” CN X was called that because of its wide distribution extending far from the head. It arises by a series of rootlets from the lateral aspect of the medulla that merge and leave the cranium through the jugular foramen positioned between CN IX and CN XI. Distribution of vagus nerve (CN X). A. After supplying the palatine, pharyngeal, and laryngeal branches, CN X descends into the thorax. The recurrent laryngeal nerves ascend to the larynx, the left from a more inferior (thoracic) level. In the abdomen, the anterior and posterior vagal trunks demonstrate further asymmetry as they supply the terminal esophagus, stomach, and intestinal tract as far distally as the left colic flexure. B. Enlarged view of lower esophageal plexus transitioning to anterior and posterior vagal trunks.
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Neuro-Endovascular Surgery | Vascular Neurology | Neurocritical Care | Memorial Healthcare System
Understanding cerebrovascular flow & physiology is the key to being able to best help patients with neurovascular complaints and to achieving the best outcomes. While most cases of dizziness emanate from the inner ear, some of these can be from a vascular/flow issue. Recent case of a 65yo patient at Memorial Healthcare System with persistent disabling dizziness and occasional double vision, punctate strokes in the left occipital/temporal and cerebellar hemisphere on maximum medical therapy with dual antiplatelets and statin. Symptoms continued to occur despite medications, brought in for a cerebral angiogram after non-invasive imaging. Right vertebral ending in PICA, left vertebral found to have a focal high-grade flow limiting stenosis in V1 segment. Some supply to the basilar from pcoms but not enough. Treated with a balloon-mounted drug eluting stent 4 x 18mm with good stent expansion and apposition(subnominal inflation). Cat 5 intermediate catheter provided the perfect amount of support for a tight loop of the vertebral origin. Complete resolution of dizziness/double vision post procedure, being discharged home the next day. Brijesh P Mehta, M.D. #vertebrobasilarinsufficiency #cerebrovascular #neuro
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❓ ❓ How anaesthesia affects cerebrovascular morbidity and mortality in those with brain frailty? 👏 A new commentary authored by Samuel C. Barnes, Lucy Beishon, Md Tanvir Hasan, Thompson Robinson & Jatinder Minhas is now online: Cerebral haemodynamics, anaesthesia and the frail brain For more details 👇 https://lnkd.in/gMBhsT2Q #anaesthesia #brain #GeriatricAnesthesia
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