By J. Amul. American University. 2018.
Ulnar styloid fractures are frequently present but are after 2 weeks buy generic accutane 10mg online skin care for winter, will often show these occult fractures generic 40 mg accutane mastercard acne 911 zit blast. The most common va- dislocated from the lunate and the lunate is subluxed from riety of distal radial fracture is one in which the distal frac- the radius. This term is confusing, since all of these pat- ture fragment is displaced and angulated in a dorsal direc- terns are dislocations of the midcarpal joint. This fracture was first described by Abraham Colles, Other, less-common, carpal dislocations include the in 1814, and now bears his name. These are the result of high-energy this fracture 81 years before the discovery of X-rays, he did trauma and separate the carpus into medial and lateral not know the detail or radiographic manifestations of this portions. His real contribution was to point out that these are frequently require surgical repair. He showed that they could be re- duced and splinted and could heal with excellent results. Carpometacarpal dislocations When the deformity is in the opposite direction (palmar) we refer to the injury as a Smith’s fracture. When there is no Perhaps the most commonly missed serious injury to the deformity, the injury should be described simply as a hand and wrist is dislocation along the carpometacarpal nondisplaced, distal, radial fracture. These injuries can be surprisingly subtle on initial ra- styloid commonly occur in association with distal radial diographs. In spite of this, they are serious injuries that usu- fractures but are not always present. There are two keys to finding change the designation as a Colles’, Smith’s or nondis- them:. One of the most important findings to ob- tures of the distal carpals or proximal metacarpals; (2) on at serve in these fractures is extension into the distal radial ar- least one of the standard views, the affected car- ticular surface. Intra-articular fractures often require surgi- pometacarpal joints will show loss of parallelism. So, the important point to remember is: diocarpal dislocations, they are referred to as “Barton’s frac- any time a fracture at the carpometacarpal junction is seen, tures”. If the dorsal lip is fractured, the carpus will be dis- a dislocation must be assumed, until proven otherwise. This is referred to as a “dorsal Barton’s frac- CT or fluoroscopy may be required to resolve this issue. Wilson Metacarpal Injuries The latter are most commonly seen around times of cel- ebration with fireworks. In the United States, these in- While metacarpal fractures may occur in FOOSH, they are juries most frequently occur around July Fourth and New more frequent when the fist is closed. Penetrating injuries are very variable, de- are most commonly associated with punching, usually dur- pending on the location and force of penetration. A well placed punch will line up the sec- are often devastating, resulting in multiple fractures, se- ond metacarpal with the radius, often resulting in a frac- vere soft-tissue loss and a hand beyond repair. However, most bare- ologist’s job is simple: describe what is broken and what fisted fighters have not been trained to punch correctly and is missing. Penetrating trauma rarely presents the same strike glancing blows with the ulnar aspect of the fist. These blows frequently result in fractures of the fifth metacarpal neck. This has been called the “boxers fracture” Advanced Imaging but would be more accurately defined as the “amateur street-fighter’s fracture”. The head of the metacarpal is typ- As stated earlier, CT and MRI have a limited role in di- ically displaced and angulated in a palmar direction. However, in certain sit- fracture is allowed to heal in this position, the next time the uations, they can prove invaluable. It is far more reliable than radiography pressed and allows the fourth to receive the maximum for the assessment of fracture healing.
Two men of Alexandria purchase accutane 20mg skin care 999, Herophilus and Erasistratus generic accutane 5 mg otc acne yeast, made lasting contributions to the study of anatomy. History of Anatomy © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 Chapter 1 History of Anatomy 11 rate, he also had notions that were primitive and mystical. He thought, for example, that the cranial nerves carried animal spir- its and that muscles contracted because of distention by spirits. He also believed that the left ventricle of the heart was filled with a vital air spirit (pneuma) that came in from the lungs, and that the arteries transported this pneuma rather than blood. Both Herophilus and Erasistratus were greatly criticized later in history for the vivisections they performed. Herophilus was described as a butcher of men who had dissected as many as 600 living human beings, some- times in public demonstrations. Roman Era In many respects, the Roman Empire stifled scientific advance- ments and set the stage for the Dark Ages. The approach to sci- ence shifted from theoretical to practical during this time. Few dissections of cadavers were performed other than in attempts to determine the cause of death in criminal cases. Medicine was not preventive but was limited, almost without exception, to the treatment of soldiers injured in battle. Later in Roman history, laws were established that attested to the influence of the Church on medical practice. According to Roman law, for exam- ple, no deceased pregnant woman could be buried without prior removal of the fetus from the womb so that it could be baptized. The scientific documents that have been preserved from the Roman Empire are mostly compilations of information ob- FIGURE 1. New anatomical information was scant, and for the most part was derived from dissections of animals other than human. Through vivisections and dissections of human cadavers, he pro- Most of what is currently known about the Alexandrian school vided excellent descriptions of the skull, eye, various visceral or- of medicine is based on the writings of the Roman encyclopedist gans and organ relationships, and the functional relationship of Cornelius Celsus (30 B. Two monumental works by tion into an eight-volume workcalled De re medicina. He re- only limited influence in his own time, however, probably be- garded the brain as the seat of intelligence and described many of cause of his use of Latin rather than Greek. It was not until the its structures, such as the meninges, cerebrum, cerebellum, and Renaissance that the enormous value of his contribution was fourth ventricle. A Greek living under Roman domination, he tions than structure and is frequently referred to as the father of was certainly the most influential writer of all times on medical physiology. For nearly 1,500 years, the writings of Galen repre- servations on the heart, vessels, brain, and cranial nerves. Erasis- sented the ultimate authority on anatomy and medical treat- tratus noted the toxic effects of snake venom on various visceral ment. Galen probably dissected no more than two or three organs and described changes in the liver resulting from various human cadavers during his career, of necessity limiting his diseases. Although some of his writings were scientifically accu- anatomical descriptions to nonhuman animal dissections. History of Anatomy © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 12 Unit 1 Historical Perspective Middle Ages The Middle Ages, frequently referred to as the Dark Ages, began with the fall of Rome to the Goths in A. The totalitarian Christian Church suppressed science and medical activity stagnated. Human existence con- tinued to be miserably precarious, and people no longer felt ca- pable of learning from personal observation. If mysterious deaths occurred, ex- aminations by inspection and palpation were acceptable. During the plague epidemic in the sixth century, however, a few necrop- sies (nek′rop-se¯z) and dissections were performed in the hope of determining the cause of this dreaded disease (see fig. During the Crusades soldiers cooked the bones of their dead comrades so that they could be returned home for proper burial. Even this act, however, was eventually considered sacrile- gious and strongly condemned by the Church.
Both can occur with the muscles may atrophy (shrink or become acute and chronic abuse of alcohol accutane 40 mg fast delivery acne rash. The 212 CHAPTER 7 CONDITIONS RELATED TO SUBSTANCE USE severity of these conditions depends on effects of both fatty liver and alcoholic the individual buy accutane 20 mg low price acne neonatorum. Individuals who continue to ditions produce only a mild discomfort, abuse alcohol, however, have a high but in other instances, the irritation and chance of developing cirrhosis. Obviously, absti- nence from alcohol is a major treatment Cirrhosis is most frequently caused by objective. It Esophageal Varices involves the reaction of the liver to injury by hepatotoxins (substances that are Some individuals who abuse alcohol harmful to the liver), in this case, alcohol. Circulation within the Esophageal varices are usually a complica- liver becomes less efﬁcient, resulting in tion of cirrhosis. Because of the ﬁbrous Treatment is directed toward controlling changes that occur in the liver with cirrho- hemorrhage, usually by inserting a special sis, there is increased pressure in the por- tube (Sengstaken-Blakemore tube) into the tal vein, a condition known as portal esophagus. Backﬂow of blood results in inﬂated to exert pressure against the bleed- the enlargement of the spleen (splenom- ing vein. Because the esophagus needs rest egaly), accumulation of fluid in the in order to heal, other types of feeding abdominal cavity (ascites), and develop- may be instituted until the esophagus is ment of esophageal varices. Others experience Alcoholic Hepatitis weakness, nausea, loss of appetite (ano- rexia), and jaundice (yellow discoloration During alcohol metabolism, fat is de- of the skin and whites of the eyes due to posited in the liver. When individuals con- the accumulation of bile pigments in the sume excessive amounts of alcohol, the blood). Treatment of cirrhosis is largely accumulation of fat enlarges the liver, a symptomatic, but abstinence from alcohol condition called fatty liver. Individuals with continue to consume alcohol, liver cells cirrhotic changes in the liver have an may die, causing the liver to become increased risk of cancer of the liver. This inﬂammatory condition, in who continue to abuse alcohol despite cir- which the liver is usually enlarged and rhotic changes in the liver, or despite oth- painful, is known as alcoholic hepatitis. Use Disorders Involving Other Substances 213 Pancreatitis infant called fetal alcohol syndrome. The amount of alcohol that pregnant women A variety of conditions other than alco- must consume before the fetus is injured hol abuse may cause pancreatitis (inﬂam- is unknown and appears to vary with the mation of the pancreas). Fetal alcohol syndrome is pancreatitis, however, is a form of pancre- characterized by prenatal and postnatal atitis that develops in susceptible individ- growth retardation, microcephaly (abnor- uals after chronic alcohol abuse. In this mal smallness of the head), abnormalities condition, the pancreatic ducts become of the nervous system, and facial disﬁgura- obstructed. Other congenital anomalies may normally secretes into the small intestine include mental retardation, as well as mus- to aid in digestion become active while culoskeletal and cardiac abnormalities. As a result, the pancreas essentially USE DISORDERS INVOLVING OTHER begins to digest itself, causing progressive SUBSTANCES degeneration with scarring and calciﬁca- tion of pancreatic tissues. Pancreatic func- Caffeine and Nicotine tion is often severely curtailed. Chronic pancreatitis can lead to severe disability Tolerance and dependence have been from pain, malabsorption of nutrients established for both caffeine and nicotine, resulting in weight loss, and diabetes mel- although these substances are not com- litus secondary to the destruction of the monly thought of as substances of abuse. Caffeine is commonly obtained from cof- Treatment of pancreatitis is directed fee or tea, but it may also be consumed in toward halting destruction of tissue and soft drinks, chocolate, and many over-the- alleviating the symptoms. Caffeine is a powerful cen- conditions of the gastrointestinal tract, tral nervous system stimulant (Ochs, effective treatment requires that individ- Holmes, & Karst, 1992) that can also affect uals abstain from alcohol. If they no cardiac muscle, elevate blood pressure, longer consume alcohol, many individu- increase gastric acid secretion, and have a als recover from alcoholic pancreatitis to diuretic effect. If they continue to disabling conditions as well as generate drink, however, the prognosis is general- new symptoms. Headaches Reproductive System Problems that are not relieved by regular analgesics are a manifestation of withdrawal from Excessive alcohol use has been found to caffeine. Although caffeine abuse in itself lower the level of the male hormone is not usually disabling, it may aggravate testosterone, which, in turn, has been relat- preexisting conditions, such as ulcer dis- ed to decreased libido and, in some ease, hypertension, or cardiac arrhythmia. Excessive alcohol The availability of a large number of decaf- intake also increases the level of epineph- feinated products makes it possible to de- rine and other hormones. The 214 CHAPTER 7 CONDITIONS RELATED TO SUBSTANCE USE amount of dependence is proportional to and alprazolam (Xanax). Nicotine er doses to produce sleep, they are called consumed through smoking, chewing, or hypnotics.
Because of the dearth of 5-HT1B selective ligands order 5 mg accutane visa acne 8 weeks pregnant, the gross physiological effects that result from activation of these receptors is largely uncharacterised purchase 20mg accutane amex acne light therapy. Activation of these receptors could also contribute to the anti- migraine effects of sumatriptan, a non-selective 5-HT1B/1D agonist (but see below). An interesting development in this area is the possibility that there could be an endogenous ligand, for these receptors: 5-HT-moduline. This is a tetrapeptide that is released from neurons and is claimed to be the first allosteric modulator of a G protein- coupled receptor to be identified so far. Functionally, 5-HT-moduline behaves like a 5-HT1B antagonist and so increases terminal release of 5-HT (Massot et al. Soon after characterisation of the 5-HT1D receptor, which was found in certain species (e. These receptors were therefore regarded as species variants and came to be described as the 5-HT1B/1D subtype. Since then, another 5-HT1 receptor subtype has been identified and current nomenclature dictates that this is the (new) 5-HT1D receptor. So far, little is known about this novel 5-HT1D receptor but, in the rat and human, its mRNA is found, albeit in low concentrations, in the basal ganglia, nucleus accumbens, hippocampus, frontal cortex and Raphe nuclei. It is negatively coupled to adenylyl cyclase and is possibly located presynaptically, on both the 5-HT neuronal cell body and terminals, but this has yet to be confirmed. Interest in this receptor has been generated by the possibility that its activation accounts for the anti-migraine effects of the non-selective 5-HT1B/1D agonist, sumatriptan. The exact process(es) that account for this action are unresolved but 5-HYDROXYTRYPTAMINE 201 favoured possibilities include vasoconstriction of cerebral arteries and/or blockade of neurogenic pain and inflammation generated by vascular afferents within the trigeminal nucleus. Because mRNA for the 5-HT1B receptor is not found in this nucleus in humans, activation of the 5-HT1D receptor is thought to be responsible for these effects. Radioligand binding and the distribution of mRNA for the 5-ht1E receptor suggest that it is found mainly in the striatum but it also seems to be present in the amygdala, frontal cortex and globus pallidus, to some extent. However, the lack of specific ligands has prevented their pharmacological characterisation. Recently, the anti-migraine drug, sumatriptan, has been found to bind to 5-ht1F receptors with an affinity similar to that for 5-HT1B/1D receptors and so they might have a role in migraine. They are coupled to phospholipase A and have an excitatory effect on the host cell as a result of the ensuing reduction in K conductance. The many well-known agonist ligands for this receptor include DOI (1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane hydrochloride), DOM (2,5-dimethoxy-4-methylamphetamine) and LSD. Preclinical studies reinforce the view that 5-HT2A (and possibly 5-HT2C) receptor activation underlies the hallucinogenic effects of these compounds (Krebs- Thomson, Paulus and Geyer 1998). This is consistent with recent evidence that all the atypical neuroleptics, such as clozapine, risperidone and olanzepine, act as antagonists at this receptor, an action that could well contribute to their therapeutic effects in schizophrenia. In addition to their psychotropic effects, activation of 5-HT2A receptors induces hyperthermia, which could explain this dangerous action of MDMA. Finally, an unusual feature of these receptors is that they are downregulated by prolonged exposure to antagonists, as well as agonists. The reason for this is uncertain but it could suggest that drugs which hitherto have been regarded as antagonists are, in fact, inverse agonists. However, little is known about these receptors, mainly because of the shortage, until recently, of selective ligands, their low density and the limited distribution of their mRNA in the brain. However, as information accrued from cloning studies, pharmacological characterisation, and discovery of its second messenger system, it became evident that this receptor shared the characteristics of the 5-HT2 receptor family, rather than those of a 5-HT1 receptor. The switch in classification from a 5-HT1C to a 5-HT2C receptor explains the gap in the 5-HT1 receptor family. The 5-HT2C receptor was first found in the choroid plexus, where it is thought to regulate the formation of CSF, but it has since been found in cortical and limbic areas as well as the basal ganglia. In the choroid plexus, at least, its actions seem to be mediated by activation of phospholipase C with a resulting depolarisation of the host cell.
Median Section (C) Between the hemispheres lies the dien- cephalon (C14); the corpus callosum (C15) above it connects the two hemispheres buy accutane 10mg mastercard skin care guru. The corpus callosum forms a fiber plate; its oral curvature encloses a thin wall segment of the hemisphere buy accutane 30mg free shipping acne 30s, the septumpellucidum (C16) (p. In the anterior wall of the third ventricle lies the anterior commissure (C20) (containing the crossing fibers of the olfactory brain); at its base lie Kahle, Color Atlas of Human Anatomy, Vol. Anatomy of the Brain, Lateral View and Median Section 11 9 8 7 13 12 10 5 6 4 11 1 2 3 A Lateral view of the brain 32 14 B Dorsal view 9 7 24 29 19 15 16 18 25 17 26 27 20 21 28 30 22 23 31 C Median section through the brain, medial surface of the right hemisphere Kahle, Color Atlas of Human Anatomy, Vol. The ventral faces of frontal lobe (A1) and temporal lobe half of the lateral wall, which differentiates (A2), and the base of the diencephalon. The early,iscalledthebasalplate(C19)andrep- longitudinal cerebral fissure (A3) separates resentstheoriginofmotorneurons. Thedor- the two frontal lobes; at the basal surface of sal half, which develops later, is called the each hemisphere lies the olfactory lobe with alar plate (C20) and represents the origin of the olfactory bulb (A4) and the olfactory tract sensory neurons. The tract divides in the olfactorytrigone plates lies a segment (C21) from which au- (A6) into two olfactory striae which border tonomic neurons originate. Thus, a struc- the anteriorperforatedsubstance (A7); the lat- tural plan of the CNS can be recognized in ter is perforated by entering blood vessels. The pons difficult to identify in diencephalon and tel- (A12) bulges caudally and is followed by the encephalon. The cerebellum is divided into the medial, deep- lying vermis of the cerebellum (A14) and the two cerebellar hemispheres (A15). White and Gray Matter (B) Upon dissecting the brain into slices, the white and gray matter, substantia alba et grisea, become visible on the cut surfaces. The gray matter represents a concentration of neurons and the white matter the fiber tracts, or neuronal processes, which appear light because of their white envelope, the myelin sheath. In the spinal cord (B16), the gray matter lies in the center and is en- closed by the bordering white matter (as- cending and descending fiber tracts). In the brain stem (B17) and diencephalon, the dis- tribution of gray and white matter varies. In the telen- cephalon (B18), the gray matter lies at the outer margin and forms the cortex, while the white matter lies inside. Thus, the dis- tribution here is the reverse of that in the spinal cord. The arrangement in the spinal cord repre- sents a primitive state; it still exists in fish and amphibians where the neurons are in a periventricular position even in the telen- cephalon. The cerebral cortex represents the highest level of organization, which is fully developed only in mammals. Base of the Brain, White and Gray Matter, Subdivision into Lateral Zones 13 3 4 1 5 9 6 8 7 10 11 2 12 13 15 A Basal view of the brain 14 16 17 18 B Distribution of white and gray matter 20 21 19 C Longitudinal zones of the CNS Kahle, Color Atlas of Human Anatomy, Vol. During their expansion, they push the brain developed into the organ of human in- early-developed brain parts into a deeper telligence. Since the ancestors are extinct, location and bulge outward (they become the developmental sequence can only be re- prominent). In am- phibians and reptiles, the telencephalon (A1) appears as an appendix to the large ol- factory bulb (A2); mesencephalon (A3) and diencephalon (A4) lie free at the surface. Al- ready in primitive mammals (such as the hedgehog), however, the telencephalon ex- pands over the rostral parts of the brain stem; in lemurs, it completely overlays the diencephalon and mesencephalon. Thus, the phylogenetic development of the brain essentially consists of a progressive enlarge- ment of the telencephalon and a transfer of the highest integrative functions to this part of the brain. Ancient primitive structures are still retained in the human brain and are inter- mingled with new, highly differentiated structures. Therefore, when we talk about new and old components of the human brain, we refer to the brain’s evolution. The brain is neither a computer nor a thinking machine constructed according to rational principles; it is an organ that has evolved in countless variations over millions of years.
10 of 10 - Review by J. Amul
Votes: 151 votes
Total customer reviews: 151