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In addition to providing support for each of Cervical these parts of the body purchase adalat in india blood pressure zantac, the vertebrae provide attachments enlargement for muscles and fascia 20 mg adalat mastercard pulse pressure 30 mmhg, and articulation sites for other (of spinal cord) bones discount adalat 30 mg online heart attack ft thea austin eye of the tiger. The anterior rami of spinal nerves associated with the thorax, abdomen, and pelvis pass into these parts of the body from the back. Limbs The bones of the back provide extensive attachments for muscles associated with anchoring and moving the upper limbs on the trunk. This is less true of the lower limbs, ganglion which are frmly anchored to thevertebral column through articulation of the pelvic bones with the sacrum. The upper and lower limbs are innervated by anterior rami of spinal nerves that emerge from cervical and lumbosacral levels, respectively, of the vertebral column. Their spinal cord level of origin therefore becomes increasingly dissociated from their vertebral column level of exit. The foramen is joint (the joint between the articular processes), can affect formed between adjacent vertebral arches and is closely the function of the associated spinal nerve. Posterior branches of spinal nerves innervate the intrinsic • The posterior margin is formed by the articular pro muscles of the back and adjacent skin. Superior articular process Superior vertebral notch Intervertebral Joint between Interverebral disc Inferior articular process Inferior vertebral notch Fig. The skull, scap • The seven cervical vertebrae between the thorax and ulae, pelvic bones, and ribs also contribute to the bony skull are characterized mainly by their small size and framework of the back and provide sites for muscle the presence of a foramen in each transverse process attachment. Anterior Fused costal Foramen (rib) element transversarium 7 Cervical vertebrae Cervical vertebra vertebrae Thoracic vertebra vertebrae Fused costal (rib) element Lumbar vertebra Posterior 64 Fig. In the embryo, the vertebrae are formed intersegmen • Inferior to the thoracic vertebrae are fve lumbar verte tally from cells called sclerotomes, which originate from brae, which form the skeletal support for the posterior adjacent somites (Fig. Each vertebra is derived from abdominal wall and are characterized by their large size the cranial parts of the two somites below, one on each (Figs. Extending from the verte • The two laminae are flat sheets of bone that extend bral arch are a number of processes for muscle attachment from each pedicle to meet in the midline and form the and articulation with adjacent bone. The vertebral body is the weight-bearing part of the vertebra and is linked to adjacent vertebral bodies by inter A spinous process projects posteriorly and inferiorly vertebral discs and ligaments. The size of vertebral bodies from the junction of the two laminae and is a site for increases inferiorly as the amount of weight supported muscle and ligament attachment. A transverse process extends posterolaterally from The vertebral arch forms the lateral and posterior the junction of the pedicle and lamina on each side and is parts of the vertebral foramen. The vertebral foramina of all the vertebrae together Also projecting from the region where the pedicles form the vertebral canal, which contains and protects join the laminae are superior and inferior articular the spinal cord. Superior aricular process Superior vertebral notch Vertebral arch Inferior articular process Inferior vertebral notch Superior view Superolateral oblque view Fig. The seven cervical vertebrae are characterized by their small size and by the presence of a foramen in each trans The frst and second cervical vertebrae-the atlas verse process. A typical cervical vertebra has the following and axis-are specialized to accommodate movement of features (Fig. Foramen transversarium Vertebral body Uncinate process process Vertebral canal Foramen transversarium Spinous process A Superior view Anterior view Fig. Its major distinguishing feature is that it lacks a connected by an anterior arch and a posterior arch. In fact, the vertebral body of Each lateral mass articulates above with an occipital er fuses onto the body of en during development to become condyle of the skull and below with the superior articular the dens of err. The superior articular surfaces are bean shaped and concave, whereas the infe rior articular surfaces are almost circular and flat. Inferior articular facet on lateral mass of Cl The atlanto-occipital joint allows the head to nod up and down on the vertebral column. The posterior surface of the anterior arch has an articu lar facet for the dens, which projects superiorly from the vertebral body of the axis. The dens is held in position by a strong transverse ligament of atlas posterior to it and spanning the distance between the oval attachment facets on the medial surfaces of the lateral masses of the atlas. The transverse processes of the atlas are large and pro trude furtherlaterally than those of the other cervical ver tebrae and act as levers for muscle action, particularly for muscles that move the head at the atlanto-axial joints. The axis is characterized by the large tooth-like dens, which extends superiorly from the vertebral body (Figs. The anterior surface of the dens has an oval facet for articulation with the anterior arch of the atlas. The two superolateral surfaces of the dens possess cir cular impressions that serve as attachment sites for strong alar ligaments, one on each side, which connect the dens to the medial surfaces of the occipital condyles. It has two large L-shaped The twelve thoracic vertebrae areallcharacterized by their facets, one on each lateral surface, for articulation with the articulation with ribs. Each transverse process also has a facet (transverse Theposterior wall of thevertebral canal may be incom costal facet) for articulation with the tubercle of its own plete near the inferior end of the sacrum. The vertebral body of the vertebra is somewhat heart shaped when viewed from above, and the vertebral foramen Coccyx is circular. The coccyx is a small triangular bone that articulates with the inferior end of the sacrum and represents three to four Lumbar vertebrae fused coccygeal vertebrae (Fig. It is characterized Thefve lumbar vertebrae are distinguished from vertebrae by its small size and by the absence of vertebral arches and in other regions by their large size (Fig. The foramina allow structures, such as drical and the vertebral foramen is triangular in shape and spinal nerves and blood vessels, to pass in and out of the larger than in the thoracic vertebrae. An intervertebral foramen is formed by the inferior ver Sacrum tebral notch on the pedicle of the vertebra above and the The sacrum is a single bone that represents the fve fused superior vertebral notch on the pedicle of the vertebra sacral vertebrae (Fig. The foramen is bordered: the apex pointed inferiorly, and is curved so that it has a concave anterior surface and a correspondingly convex • posteriorly by the zygapophysial joint between the artic posterior surface. However, in the lumbar region, large gaps exist between the posterior components of adjacent vertebral Each intervertebral foramen is a confned space sur arches (Fig. Posterior spaces between vertebral arches In mostregions of the vertebral column, the laminae and spinous processes of adjacent vertebrae overlap to form a Space between adjacent laminae Fig. This defect occurs in as many as 1 Oo of individuals and results in failure of the posterior arch to fuse in the midline. Clinically, the patient is asymptomatic, although physical examination may reveal a tuf of hair over the spinous processes. This may contain cerebrospinal fluid (a meningocele) or a portion ofthe spinal cord (a myelomeningocele). These abnormalities may result in a variety of neurological defcits, including problems with walking and bladderfunction. The Vertebroplasty is a new technique in which the body of a procedure is performed under sedation or light general vertebra can be flled with bone cement (typically methyl anesthetic. A metal cannula is placed vertebral bodycollapse and pain from the vertebral body, through the pedicle into the vertebral body.
During parturition buy cheapest adalat heart attack vol 1 pt 15, dilatation of the cervical os can be assessed by rectal examination since it can be felt quite easily through the rectal wall 20mg adalat pulse pressure 53. Initially contained within the anal canal (1st degree) purchase adalat mastercard hypertension nursing interventions, they gradually enlarge until they prolapse on defaecation (2nd degree) and finally remain prolapsed through the anal orifice (3rd degree). Anatomically, each pile comprises: a venous plexus draining into one of the superior rectal veins; terminal branches of the corresponding superior rectal artery; and a covering of anal canal mucosa and submucosa. The so-called ‘thrombosed external pile’ is a small tense haematoma at the anal margin caused by rupture of a subcutaneous vein and is much better termed a perianal haematoma. Occasionally, abscesses lie in the pelvirectal space above levator ani, alongside the rectum and deep to the pelvic peritoneum. They are classified anatomically and may be: submucous—confined to the tissues immediately below the anal mucosa; subcutaneous—confined to the perianal skin; low-level— passing through the lower part of the superficial sphincter (most common); high-level—passing through the deeper part of the superficial sphincter; anorectal—which has its track passing above the anorectal ring and which may or may not open into the rectum. In laying open fistulae in ano, it is essential to preserve the anorectal ring if faecal incontinence is to be avoided. The anatomical basis for this probably lies in the insertion of the superficial 86 The abdomen and pelvis component of the external anal sphincter posteriorly into the coccyx; between the two limbs of the V thus formed, the mucosa is relatively unsupported and may therefore be torn by a hard faecal mass at this site. Arterial supply of the intestine The alimentary tract develops from the fore-, mid- and hind-gut; the arterial supply to each is discrete, although anastomosing with its neigh- bour. The fore-gut comprises stomach and duodenum as far as the entry of the bile duct and is supplied by branches of the coeliac axis which arises from the aorta at T12 vertebral level (see Fig. The mid-gut extends from mid-duodenum to the distal transverse colon and is supplied by the superior mesenteric artery (Fig. Its branches are: 1the inferior pancreaticoduodenal artery; 2jejunal and ileal branches—supplying the bulk of the small intestine; 3the ileocolic artery, supplying terminal ileum, caecum and commence- ment of ascending colon and giving off an appendicular branch to the appen- dix—the most commonly ligated intra-abdominal artery; 4the right colic artery—supplying the ascending colon; 5the middle colic artery—supplying the transverse colon. The portal system of veins The portal venous system drains blood to the liver from the abdominal part of the alimentary canal (excluding the anal canal), the spleen, the pancreas and the gall-bladder and its ducts. The distal tributaries of this system correspond to, and accompany, the branches of the coeliac and the superior and inferior mesenteric arteries enumerated above; only proximally (Fig. The inferior mesenteric vein ascends above the point of origin of its artery to enter the splenic vein behind the pancreas. The superior mesenteric vein joins the splenic vein behind the neck of the pancreas in the transpyloric plane to form the portal vein, which ascends behind the first part of the duodenum into the anterior wall of the foramen of Winslow and thence to the porta hepatis. Here the portal vein divides into right and left branches and breaks up into capillaries running between the lobules of the liver. These capillaries drain into the radicles of the hepatic vein through which they empty into the inferior vena cava. Connections between the portal and systemic venous systems Normally, portal venous blood traverses the liver as described above and empties into the systemic venous circulation via the hepatic vein and infe- rior vena cava. This pathway may be blocked by a variety of causes which are classified into: 88 The abdomen and pelvis prehepatic — e. If obstruction from any of these causes occurs, the portal venous pres- sure rises (portal hypertension) and collateral pathways open up between the portal and systemic venous systems. These communications are: 1between the oesophageal branch of the left gastric vein and the oesophageal veins of the azygos system (these oesophageal varices are the cause of the severe haematemeses that may occur in portal hypertension); 2between the superior rectal branch of the inferior mesenteric vein and the inferior rectal veins draining into the internal iliac vein via its internal pudendal tributary; 3between the portal tributaries in the mesentery and mesocolon and retroperitoneal veins communicating with the renal, lumbar and phrenic veins; 4between the portal branches in the liver and the veins of the abdominal wall via veins passing along the falciform ligament from the umbilicus (which may result in the formation of a cluster of dilated veins which radiate from the navel and which are called the caput Medusae); 5between the portal branches in the liver and the veins of the diaphragm across the bare area of the liver. Astriking feature of operations upon patients with portal hypertension is the extraordinary dilatation of every available channel between the two systems which renders such procedures tedious and bloody. Numerous small nodes lying near, or even on, the bowel wall drain to intermediately placed and rather larger nodes along the vessels in the mesentery or mesocolon and thence to clumps of nodes situated near the origins of the superior and inferior mesenteric arteries. The lymphatic drainage field of each segment of bowel corresponds fairly accurately to its blood supply. High ligation of the vessels to the involved segment of bowel with removal of a wide surrounding segment of mesocolon will, therefore, remove the lymph nodes draining the area. Divi- sion of the middle colic vessels and a resection of a generous wedge of transverse mesocolon, for example, would be performed for a growth of transverse colon. The structure of the alimentary canal The alimentary canal is made up of mucosa demarcated by the muscularis mucosae from the submucosa, the muscle coat and the serosa — the last being absent where the gut is extraperitoneal. The oesophageal mucosa and that of the lower anal canal is stratified squamous; elsewhere it is columnar. At the cardio-oesophageal junction this transition is quite sharp, although occasionally columnar epithelium may line the lower oesophagus. The mucosa of the duodenum and small intestine, as well as bearing crypt-like glands, projects into the bowel lumen in villous processes which greatly increase its surface area. The duodenum is distinguished by its crypts extending deep through the muscularis mucosae and opening into an extensive system of acini in the submucosa termed Brunner’s glands. The mucosa of the large intestine is lined almost entirely by mucus- secreting goblet cells; there are no villi. The muscle coat of the alimentary tract is made up of an inner circular layer and an outer longitudinal layer. In the upper two-thirds of the oesophagus and at the anal margin this muscle is voluntary; elsewhere it is involuntary. The stomach wall is reinforced by an innermost oblique coat of muscle and the colon is characterized by the condensation of its longitudi- nal layer into three taeniae coli. The autonomic nerve plexuses of Meissner and Auerbach lie respec- tively in the submucosal layer and between the circular and longitudinal muscle coats. The gastrointestinal tract 91 At an early stage rapid proliferation of the gut wall obliterates its lumen and this is followed by subsequent recanalization. The fore-gut becomes rotated with the development of the lesser sac so that the original right wall of the stomach comes to form its posterior surface and the left wall its anterior surface. The vagi rotate with the stomach and therefore lie anteriorly and posteriorly to it at the oesophageal hiatus. This rotation swings the duodenum to the right and the mesentery of this organ then blends with the peritoneum of the posterior abdominal wall —this blending process is termed zygosis (see p. The mid-gut enlarges rapidly in the 5-week fetus, becomes too large to be contained within the abdomen and herniates into the umbilical cord. The apex of this herniated bowel is continuous with the vitello-intestinal duct and the yolk sac, but this connection, even at this early stage of fetal life, is already reduced to a fibrous strand. The axis of this herniated loop of gut is formed by the superior mesen- teric artery, which demarcates a cephalic and a caudal limb. The cephalic element develops into the proximal small intestine; the caudal segment dif- ferentiates into the terminal 2 feet (62cm) of ileum, the caecum and the colon as far as the junction of the middle and left thirds of the transverse colon. Abud which develops on the caudal segment indicates the site of subse- quent formation of the caecum; it may well be that this bud delays the return of the caudal limb in favour of the cephalic gut during the subse- quent reduction of the herniated bowel. The mid-gut loop first rotates anti-clockwise through 90° so that the cephalic limb now lies to the right and the caudal limb to the left. The cephalic limb returns first, passing upwards and to the left into the space left available by the bulky liver. In doing so, this mid-gut passes behind the superior mesenteric artery (which thus comes to cross the third part of the duodenum) and also pushes the hind-gut—the definitive distal colon—over to the left. When the caudal limb returns, it lies in the only space remaining to it, superficial to, and above, the small intestine with the caecum lying immedi- ately below the liver. The caecum then descends into its definitive position in the right iliac fossa, dragging the colon with it. The transverse colon thus comes to lie in front of the superior mesenteric vessels and the small intestine.
Syndromes
An appropri- Other Adverse Effects ate clinical response to these symptoms would be to re- Cholestatic jaundice is observed infrequently cheap adalat 30mg visa arteria labyrinth, usually duce the dose or discontinue the antipsychotic agent during the first few weeks of treatment buy 30 mg adalat fast delivery blood pressure spikes. This is thought and then eliminate all drugs with central anticholinergic to be a hypersensitivity reaction and is usually mild and action buy discount adalat on line arteriosclerosis, such as antidepressants. Cutaneous allergic reactions are occasion- ance the risks of continuing treatment in a patient with ally reported. Both types of problems normally disap- tardive dyskinesia with the benefits of antipsychotic ad- pear upon changing to an antipsychotic from a different ministration. The most serious ocular complication is pigmen- ical emergency involving extrapyramidal symptoms that tary retinopathy associated with high-dose thioridazine occurs in about 1% of patients receiving antipsychotics. The condition is marked by hyper- Agranulocytosis is a potentially catastrophic idio- thermia or fever, diffuse muscular rigidity with severe syncratic reaction that usually appears within the first 3 extrapyramidal effects, autonomic dysfunction such as months of therapy. Although the incidence is extremely increased blood pressure and heart rate, and fluctuating low (except for clozapine), mortality is high. Neuroleptic malignant syn- fever, sore throat, or cellulitis is an indication for dis- drome is most common in males, with about 80% of continuing the antipsychotic and immediately conduct- cases occurring in patients under 40 years of age. Treatment should include general supportive measures, Contraindications for antipsychotic therapy are such as rehydration and body cooling; antipsychotic few; they may include Parkinson’s disease, hepatic fail- therapy should be discontinued. Overdoses of antipsychotics are agents such as bromocriptine has been employed to rarely fatal, except for thioridazine, which is associated control the muscular rigidity and hyperthermia. For other agents gastric Autonomic and Endocrine Effects lavage should be attempted even if several hours have elapsed since the drug was taken, because gastroin- Most antipsychotics have both -adrenergic and cholin- testinal motility is decreased and the tablets may still ergic antagonist activities, and blocking actions at hista- be in the stomach. Moreover, activated charcoal effec- mine and serotonin receptors also contribute to the au- tively binds most of these drugs and can be followed by tonomic effects of some agents. The hypotension often responds to and depression of medullary cardiovascular centers re- fluid replacement or pressor agents such as norepi- sulting from 1-adrenoceptor blockade is particularly nephrine. Typically, autonomic Because of their multiple effects, antipsychotic drugs signs can be controlled by adjustment of dose. Which drug may be useful in the management of (C) Flumazenil the neuroleptic malignant syndrome, although it can (D) Clozapine worsen the symptoms of schizophrenia? The question describes the pharmacological pro- (E) Increased tolerance to antipsychotic agents file of a high-potency classical antipsychotic agent, 3. Which neuroleptic agent has the lowest likelihood most likely of the butyrophenone or phenothiazine of producing tardive dyskinesia? Thioridazine is a low-potency piperidine phe- (A) Imipramine nothiazine agent with significant affinity for 1- (B) Chlorpromazine adrenergic and muscarinic receptors, having a high (C) Clozapine potential for sedation as a side effect. Haloperidol is (D) Fluoxetine a high-potency butyrophenone with its primary ac- (E) Thiothixene tion at the D2 dopaminergic receptor, so it produces 4. Which clinical condition poses the greatest concern a significant incidence of extrapyramidal toxicity to a patient on antipsychotic therapy? James began haloperidol therapy for schizo- convulsant; neither possesses significant antipsy- phrenia and within several weeks developed chotic properties. This question concerns the most important ex- choses were well controlled, he was switched to an- trapyramidal reaction to long-term antipsychotic other agent, thioridazine, which proved to be as ef- administration—tardive dyskinesia—and its gener- fective as haloperidol in managing his primary ally accepted basis. Although some tolerance to the condition and did not result in the undesirable sedative effects of antipsychotics can occur, there is symptoms. However, a decrease in that of haloperidol, it also has much greater an- dopamine synthesis has not been linked with tar- timuscarinic activity. On the contrary, lower dopamine sate for dopamine receptor blockade in the nigro- tone would more resemble a parkinsonian state, striatal tract, so that extrapyramidal function is whereas in tardive dyskinesia, antidopaminergic more appropriately maintained. Thioridazine has drugs tend to suppress the dyskinetic symptoms, greater 1-adrenergic blocking activity than and dopaminergic agonists worsen the condition. The neuroleptic malignant syndrome is an infre- There is no evidence that the antipsychotics lead to quent extrapyramidal reaction with a relatively high loss of striatal cholinergic neurons. It may result from that occurs most commonly after long-term admin- too-rapid block of dopaminergic receptors in indi- istration of high-potency butyrophenone, thioxan- viduals who are highly sensitive to the extrapyrami- thene, or phenothiazine. Chlorpromazine is a low-potency phe- sists of control of fever, use of muscle relaxants, and nothiazine agent with moderate potential to cause administration of the dopamine agonist bromocrip- extrapyramidal signs. Clozapine is well known to tine, which is likely to worsen the psychotic symp- have the lowest potential for producing tardive toms. Antipsychotic drugs and have antiemetic properties but generally are more neuroplasticity: Insights into the treatment and neu- potent than is necessary to treat motion sickness. A clinical review of cognitive Haloperidol has high affinity for D2-dopaminergic therapy for schizophrenia. She started with haloperidol and has been reported to salvage as many as 50% of then after several months switched to thiothixene. While her extrapyramidal signs with these agents Clozapine does not have the status of a first-line were not unacceptable, the frequency of her acute agent because of its undesirable side effects. De psychotic episodes marked by paranoid delusions novo seizures occur in 2 to 5% of treated patients, was not substantially diminished. The significance was also given a trial of thioridazine with a similar of agranulocytosis is not the incidence (1–2%) but clinical response to those of the earlier agents. As antipsychotic agent would be the most appropriate a result, weekly blood counts are mandatory for pa- next choice for this patient? Patients should also be concerns with the use of this drug, and what precau- alert for sudden onset of any fever or chills. Other tions should be taken during therapy with this atypical antipsychotics, such as risperidone and agent? However, these terms abuse is the production of hazardous or harmful ef- may be applied when a legally obtainable medication fects to the individual and/or to society. The etiology of is used excessively and for unintended purposes or is substance abuse is a complicated phenomenon that is diverted to someone else’s use. Inappropriate use, or abuse, is menting behavior and sometimes an inappropriate at- 406 35 Contemporary Drug Abuse 407 tempt at self-medication to treat a real or perceived Chronic use of a drug over a long period sometimes disease state. It is also clear that drug abuse is a func- produces a state of tolerance that may be classified as tion of the pharmacology of each drug. The abused substances produce an effect on the brain that degree of tolerance is generally proportional to the drug is perceived as desirable and will initiate drug-seeking dose and the duration of use. However, tolerance to many of the other acute diverse backgrounds that adopting a common terminol- effects also generally develops. Termination of drug ogy for terms such as addiction and dependence has abuse may create a condition of drug abstinence, which been difficult. These terms are best defined in the con- coincides with the emergence of a measurable physical text of the pattern and consequences of drug use. This abstinence syndrome is an indication of Regardless of the characteristics of the drug-induced in- dependence, is often referred to as drug withdrawal, and toxication, the properties of the drug that are responsi- was once termed physical dependence to distinguish it ble for drug-seeking behavior are often referred to as from psychological dependence. These drugs produce effects tation, or tolerance, to repeated administration of drug is that are so desirable that the user is compelled to obtain responsible for physical dependence. Typically, espe- Epidemiological studies indicate that most individu- cially during the initial stages of drug addiction, the als who abuse any one drug often also abuse, or primary reinforcing property is the production of eu- coabuse, other drugs during the same period.
