Lynne M. Sylvia, PharmD

• Senior Clinical Pharmacy Specialist
• Cardiology, Tufts Medical Center
• Clinical Professor, School of Pharmacy, Northeastern University, Boston, Massachusetts

T12 L1 Iliohypogas tric nerve Ilio-inguinal nerve Genitofemoral nerve L3 Lateral cutaneous nerve of thigh L4 To iliacus mus cle Femoral nerve Obturator nerve To lumbos acral trunk L2 Iliohypogastric and ilio-inguinal nerves (L1) the iliohypogastric and ilio-inguinal nerves arise as a single trunk from the anterior ramus of nerve L1 treatment naive definition dramamine 50 mg purchase visa. Either before or soon after emerging from the lateral border of the psoas major muscle medications such as seasonale are designed to buy dramamine 50 mg overnight delivery, this single trunk divides into the iliohypogastric and the ilio-inguinal nerves medicine 5e 50 mg dramamine buy mastercard. It pierces the transversus abdominis muscle and continues anteriorly around the body between the transversus abdominis and internal oblique muscles medications related to the blood trusted dramamine 50 mg. Above the iliac crest medications nursing purchase dramamine 50 mg on-line, a lateral cutaneous branch pierces the internal and external oblique muscles to supply the posterolateral gluteal skin. The remaining part of the iliohypogastric nerve (the anterior cutaneous branch) continues in an anterior direction, piercing the internal oblique just medial to the anterior superior iliac spine as it continues in an obliquely downward and medial direction. Becoming cutaneous, just above the super cial inguinal ring, after piercing the aponeurosis of the external oblique, it distributes to the skin in the pubic region. Ilio-inguinal nerve the ilio-inguinal nerve is smaller than, and inferior to , the iliohypogastric nerve as it crosses the quadratus lumborum muscle. Its course is more oblique than that of the iliohypogastric nerve, and it usually crosses part of the iliacus muscle on its way to the iliac crest. Near the anterior end of the iliac crest, it pierces the transversus abdominis muscle, and then pierces the internal oblique muscle and enters the inguinal canal. The ilio-inguinal nerve emerges through the super cial inguinal ring, along with the spermatic cord, and provides cutaneous innervation to the upper medial thigh, the root of the penis, and the anterior surface of the scrotum in men, or the mons pubis and labium majus in women. Genitofemoral nerve (L1 and L2) the genitofemoral nerve arises from the anterior rami of the nerves L1 and L2. It passes downward in the substance of the psoas major muscle until it emerges on the anterior surface of psoas major. It then descends on the surface of the muscle, in a retroperitoneal position, Subcos tal nerve Iliohypogas tric nerve Ilio-inguinal nerve Lateral cutaneous nerve of thigh Subcos tal nerve (T12) Ps oas major mus cle Iliohypogas tric nerve (L1) Ilio-inguinal nerve (L1) Genitofemoral nerve (L1,L2) Iliacus mus cle Femoral nerve Genitofemoral nerve Obturator nerve Lateral cutaneous nerve of thigh (L2,L3) Femoral nerve (L2 to L4) Obturator nerve (L2 to L4) Lumbos acral trunks (L4,L5) 204. Regional anatomy · Posterior abdominal region T10 T11 T12 Lateral cutaneous branch of iliohypogas tric nerve (L1) Anterior cutaneous branch of iliohypogas tric nerve (L1) Ilio-inguinal nerve (L1) Femoral branch of genitofemoral nerve (L1,L2) Lateral cutaneous nerve of thigh (L2,L3) Cutaneous branch of obturator nerve (L2 to L4) Intermediate cutaneous from femoral nerve Femoral nerve (L2 to L4) Medial cutaneous from femoral nerve 4 T10 T11 T12 Genitofemoral nerve (L1,L2) Ilio-inguinal nerve (L1) Lateral cutaneous nerve of thigh (L2,L3) Obturator nerve (L2 to L4) T12 L1 Saphenous nerve from femoral nerve. The genital branch continues downward and enters the inguinal canal through the deep inguinal ring. It continues through the canal and: In men, innervates the cremasteric muscle and terminates on the skin in the upper anterior part of the scrotum; and In women, accompanies the round ligament of the uterus and terminates on the skin of the mons pubis and labium majus. The femoral branch descends on the lateral side of the external iliac artery and passes posterior to the inguinal ligament, entering the femoral sheath lateral to the femoral artery. It pierces the anterior layer of the femoral sheath and the fascia lata to supply the skin of the upper anterior thigh. The lateral cutaneous nerve of thigh supplies the skin on the anterior and lateral thigh to the level of the knee. Obturator nerve (L2 to L4) Lateral cutaneous nerve of thigh (L2 and L3) the lateral cutaneous nerve of thigh arises from the anterior rami of nerves L2 and L3. It emerges from the lateral border of the psoas major muscle, passing obliquely downward across the iliacus muscle toward the anterior superior iliac spine. It descends in the psoas major muscle, emerging from its medial side near the pelvic brim. The obturator nerve continues posterior to the common iliac vessels, passes across the lateral wall of the pelvic cavity, and enters the obturator canal, through which the obturator nerve gains access to the medial compartment of the thigh. In the area of the obturator canal, the obturator nerve divides into anterior and posterior branches. On entering the medial compartment of the thigh, the two branches are separated by the obturator externus and adductor brevis muscles. Throughout their course through the medial compartment, these two branches supply: articular branches to the hip joint, muscular branches to obturator externus, pectineus, adductor longus, gracilis, adductor brevis, and adductor magnus muscles, cutaneous branches to the medial aspect of the thigh, and 205 Abdomen in association with the saphenous nerve, cutaneous branches to the medial aspect of the upper part of the leg, and articular branches to the knee joint. Femoral nerve (L2 to L4) the femoral nerve arises from the anterior rami of nerves L2 to L4. It descends through the substance of the psoas major muscle, emerging from the lower lateral border of the psoas major. Continuing its descent, the femoral nerve lies between the lateral border of the psoas major and the anterior surface of the iliacus muscle. It is deep to the iliacus fascia and lateral to the femoral artery as it passes posterior to the inguinal ligament and enters the anterior compartment of the thigh. Muscular branches innervate the iliacus, pectineus, sartorius, rectus femoris, vastus medialis, vastus intermedius, and vastus lateralis muscles. The true pelvis (lesser pelvis) is related to the inferior parts of the pelvic bones, sacrum, and coccyx, and has an inlet and an outlet. This cavity is continuous superiorly with the abdominal cavity and contains and supports elements of the urinary, gastrointestinal, and reproductive systems. The perineum contains and supports the external genitalia and external openings of the genitourinary and gastrointestinal systems. Pelvic bone the pelvic bone is irregular in shape and has two major parts separated by an oblique line on the medial surface of the bone. The pelvic bone below this line represents the lateral wall of the true pelvis, which contains the pelvic cavity. The linea terminalis is the lower two-thirds of this line and contributes to the margin of the pelvic inlet. The lateral surface of the pelvic bone has a large articular socket, the acetabulum, which together with the head of the femur, forms the hip joint. Inferior to the acetabulum is the large obturator foramen, most of which is closed by a at connective tissue membrane, the obturator membrane. A small obturator canal remains open superiorly between the membrane and adjacent bone, providing a route of communication between the lower limb and the pelvic cavity. The posterior margin of the bone is marked by two notches separated by the ischial spine. Regional anatomy · Pelvis 5 the greater sciatic notch, and the lesser sciatic notch. The irregular anterior margin of the pelvic bone is marked by the anterior superior iliac spine, the anterior inferior iliac spine, and the pubic tubercle. Components of the pelvic bone Each pelvic bone is formed by three elements: the ilium, pubis, and ischium. At birth, these bones are connected by cartilage in the area of the acetabulum; later, Ilium Of the three components of the pelvic bone, the ilium is the most superior in position. The ilium is separated into upper and lower parts by a ridge on the medial surface. Posteriorly, the ridge is sharp and lies immediately superior to the surface of the bone that articulates with the sacrum. This sacral surface has a large L-shaped facet for articulating with the sacrum and an expanded, posterior roughened area for the attachment of the strong ligaments that support the sacro-iliac joint. Anteriorly, the ridge separating the upper and lower parts of the ilium is rounded and termed the arcuate line. The portion of the ilium lying inferiorly to the arcuate line is the pelvic part of the ilium and contributes to the wall of the lesser or true pelvis. The upper part of the ilium expands to form a at, fanshaped "wing," which provides bony support for the lower abdomen, or false pelvis. This part of the ilium provides attachment for muscles functionally associated with the lower limb. The external (gluteal surface) of the wing is marked by lines and roughenings and is related to the gluteal region of the lower limb. The entire superior margin of the ilium is thickened to form a prominent crest (the iliac crest), which is the site of attachment for muscles and fascia of the abdomen, back, and lower limb and terminates anteriorly as the Iliac cres t Tuberculum of iliac cres t Gluteal s urface Anterior s uperior iliac s pine Ilium Is c hium P ubis. A prominent tubercle, tuberculum of iliac crest, projects laterally near the anterior end of the crest; the posterior end of the crest thickens to form the iliac tuberosity. This structure serves as the point of attachment for the rectus femoris muscle of the anterior compartment of the thigh and the iliofemoral ligament associated with the hip joint. The superior pubic ramus projects posterolaterally from the body and joins with the ilium and ischium at its base, which is positioned toward the acetabulum. The sharp superior margin of this triangular surface is termed the pecten pubis (pectineal line), which forms part of the linea terminalis of the pelvic bone and the pelvic inlet. Anteriorly, this line is continuous with the pubic crest, which also is part of the linea terminalis and pelvic inlet. The superior pubic ramus is marked on its inferior surface by the obturator groove, which forms the upper margin of the obturator canal. The inferior ramus projects laterally and inferiorly to join with the ramus of the ischium. It has: a large body that projects superiorly to join with the ilium and the superior ramus of the pubis; and a ramus that projects anteriorly to join with the inferior ramus of the pubis. The most prominent feature of the ischium is a large tuberosity (the ischial tuberosity) on the posteroinferior aspect of the bone. This tuberosity is an important site for the attachment of lower limb muscles and for supporting the body when sitting. The body is attened dorsoventrally and articulates with the body of the pubic bone on the other side at the pubic symphysis. The body has a rounded pubic crest on its superior surface that ends laterally as the prominent pubic tubercle. Sacrum the sacrum, which has the appearance of an inverted triangle, is formed by the fusion of the ve sacral vertebrae Regional anatomy · Pelvis. Each of the, lateral surfaces of the bone bears a large L-shaped facet for articulation with the ilium of the pelvic bone. Posterior to the facet is a large roughened area for the attachment of ligaments that support the sacro-iliac joint. Because the transverse processes of adjacent sacral vertebrae fuse laterally to the position of the intervertebral foramina and laterally to the bifurcation of spinal nerves into posterior and anterior rami, the posterior and anterior rami of spinal nerves S1 to S4 emerge from the sacrum through separate foramina. There are four pairs of anterior sacral foramina on the anterior surface of the sacrum for anterior rami. The sacral canal is a continuation of the vertebral canal that terminates as the sacral hiatus. Sacro-iliac joints the sacro-iliac joints transmit forces from the lower limbs to the vertebral column. They are synovial joints between the L-shaped articular facets on the lateral surfaces of the sacrum and similar facets on the iliac parts of the pelvic bones. Each sacro-iliac joint is stabilized by three ligaments: the anterior sacro-iliac ligament, which is a thickening of the brous membrane of the joint capsule and runs anteriorly and inferiorly to the joint. The superior surface bears a facet for articulation with the sacrum and two horns, or cornua, one on each side, that project upward to articulate or fuse with similar downward-projecting cornua from the sacrum. These processes are modi ed superior and inferior articular processes that are present on other vertebrae. Each lateral surface of the coccyx has a small rudimentary transverse process, extending from the rst coccygeal vertebra. Vertebral arches are absent from coccygeal vertebrae; therefore no bony vertebral canal is present in the coccyx. Anterior longitudinal ligament Intervertebral foramen for L5 nerve Zyg apo phys ial jo int For pos terior s acro-iliac ligament Inte rve rte bral dis c Promontory Articular s urface For interos s eous s acro-iliac ligament Anterior s acro-iliac ligament Inte rve rte bral dis c Ilium A B. Orientation In the anatomical position, the pelvis is oriented so that the front edge of the top of the pubic symphysis and the anterior superior iliac spines lie in the same vertical plane. As a consequence, the pelvic inlet, which marks the entrance to the pelvic cavity, is tilted to face anteriorly, and the bodies of the pubic bones and the pubic arch are positioned in a nearly horizontal plane facing the ground. Clinical app Common problems with the sacro-iliac joints the sacro-iliac joints have both brous and synovial components, and as with many weight-bearing joints, degenerative changes may occur and cause pain and discomfort in the sacro-iliac region. The more circular shape is partly caused by the less distinct promontory and broader alae in women. The angle formed by the two arms of the pubic arch is larger in women (80° to 85°) than it is in men (50° to 60°). The ischial spines generally do not project as far medially into the pelvic cavity in women as they do in men. Pubic symphysis joint the pubic symphysis lies anteriorly between the adjacent surfaces of the pubic bones. The joint is surrounded by interwoven layers of collagen bers and the two major ligaments associated with it are. True pelvis the true pelvis is cylindrical and has an inlet, a wall, and an outlet. The inlet is open, whereas the pelvic oor closes the outlet and separates the pelvic cavity, above, from the perineum, below. The promontory of the sacrum protrudes into the inlet, forming its posterior margin in the midline. The margin of the pelvic inlet then crosses the sacro-iliac joint and continues along the linea terminalis. Pelvic wall Pubic tubercles Pubic arch the walls of the pelvic cavity consist of the sacrum, the coccyx, the pelvic bones inferior to the linea terminalis, two ligaments, and two muscles. Prominent medially Prominent projecting projecting is chial s pines promontory Circular pelvic inlet Heart-s haped pelvic inlet A 80­85º B 50­60º. The angle formed by the pubic arch can be approximated by the angle between the thumb and index nger for women and the angle between the index nger and middle nger for men, as shown in the insets. Sa cro-iliac joint Margin of ala Promontory Clinical app Pelvic fracture the pelvis can be viewed as a series of anatomical rings. The major bony pelvic ring consists of parts of the sacrum, ilium, and pubis, which forms the pelvic inlet. The greater and lesser sciatic foraminae, formed by the greater and lesser sciatic notches and the sacrospinous and sacrotuberous ligaments form the four bro-osseous rings. It is not possible to break one side of a bony ring without breaking the other side of the ring, which in clinical terms means that if a fracture is demonstrated on one side, a second fracture should always be suspected. Pubic tub ercle Pubic s ymphys is Pubic cres t Pecten Arcuate pubis line Linea terminalis. The smaller of the two, the sacrospinous ligament, is triangular, with its apex attached to the ischial spine and its base attached to the related margins of the sacrum and the coccyx.

Excessive iron deposition is toxic to tissues in many organs symptoms leukemia order 50 mg dramamine with amex, but heart (congestive failure) medications depression 50 mg dramamine visa, pancreas (diabetes mellitus) medicine 93 5298 order dramamine 50 mg on-line, liver (cirrhosis and hepatic failure) medications 377 order dramamine online from canada, joints (pseudogout with polyarthropathy) medications list a-z dramamine 50 mg buy lowest price, skin (dark pigmentation), and pituitary and gonads (loss of libido, impotence, amenorrhea, testicular atrophy, gynecomastia) are the most severely affected. Treatment consists of periodic phlebotomy to remove 250 mg of iron with each unit of blood. Decreased hepatic copper excretion into bile leads to copper accumulation in brain, eye, and liver. Hepatic copper accumulation results in steatosis (shown here), cholestasis, acute or chronic hepatitis, and eventual cirrhosis. Destruction of bile ductules within hepatic triads is shown here with intense mononuclear infiltrates and occasional granulomatous inflammation. Additional findings include elevations in serum alkaline phosphatase, cholesterol, and globulins. Microscopic examination shows a bile duct surrounded by marked collagenous connective tissue deposition with epithelial atrophy and luminal narrowing. Patients can have marked alkaline phosphatase elevation along with icterus and pruritus. About 70% of cases occur with idiopathic inflammatory bowel disease, particularly ulcerative colitis. Note the dark-red congested regions that represent accumulation of red blood cells within centrilobular regions. The nutmeg pattern results from congestion around the central veins, usually from right-sided heart failure. Rarely, chronic passive congestion leads to fibrosis extending between central veins-a "cardiac cirrhosis. A subcapsular adenoma such as the one shown here (right panel) may rupture, producing a hemoperitoneum. These neoplasms are composed of cells resembling normal hepatocytes, but without a lobular pattern, so that normal triads and central veins are not recognized cells; they can produce bile, with the green appearance with formalin fixation shown here (left panel). In addition to the main mass, there are smaller satellite nodules that represent either intrahepatic spread or multicentric origin of the tumor. Such masses can focally obstruct the biliary tract to increase the serum alkaline phosphatase. Primary liver cancers typically arise in the setting of chronic hepatitis and cirrhosis from increased hepatocellular proliferative activity. Worldwide, viral hepatitis B and C are the most common causes, but chronic alcohol abuse is a common cause. These cancers can appear as one large mass, or there may be small surrounding satellite nodules, or multifocal masses. Intrahepatic mass lesions are unlikely to obstruct the biliary tract completely, so hyperbilirubinemia is infrequent. Clinical findings include malaise, fatigue, weight loss, abdominal pain, and abdominal enlargement. Note the nodule in the left panel that is architecturally different from and more cellular than the surrounding cirrhotic liver. The most common risk factor in the United States is primary sclerosing cholangitis, although cholangiocarcinoma is more common in parts of the world where infection with trematodes (liver flukes), such as Clonorchis sinensis, occurs. Cholangiocarcinomas do not make bile, but the cells do make mucin, and they can be almost impossible to distinguish from metastatic adenocarcinoma. Some of the larger masses show central necrosis, producing a grossly umbilicated appearance when seen beneath the hepatic capsule. The obstruction from such masses generally elevates the serum alkaline phosphatase, but not all bile ducts are obstructed, so that hyperbilirubinemia is typically not present. Of all neoplasms involving the liver, metastases are the most common because the liver is a good place for circulating neoplastic cells to settle down and grow. As the metastases enlarge, they outgrow their blood supply, leading to central necrosis. Sufficient hepatic function is typically retained, so liver failure is unlikely to occur from metastases. One minor variation is the small yellowish bulbous projection on the right-a phrygian cap-resulting from a folded fundus. The muscularis of the gallbladder contracts under the influence of cholecystokinin secreted by enteroendocrine cells of the small intestine with passage of food from the stomach into the duodenum, particularly fatty food. Modern gallbladders work harder than ancient gallbladders because of increasing dietary fat from such sources as fast food and ice cream. The location of the gallbladder on the inferior surface of the hepatic right lobe varies among 5% to 10% of the population, but congenital gallbladder anomalies, such as agenesis, are rare. Beneath the lamina propria is a muscularis, and not seen here surrounding the gallbladder are a connective tissue layer and serosa. The gallbladder mucosa transports sodium out of the bile, passively followed by chloride and water, leading to bile concentration. Bile excreted by the liver and stored in the gallbladder becomes more concentrated. The bile includes bile salts such as cholic and chenodeoxycholic acid, lecithin, calcium bilirubinate, and cholesterol. An imbalance in the relative concentrations of these bile components predisposes to precipitation and stone formation. Genes encoding proteins that transport biliary lipids, including the D19H variant, may contribute 10% of the risk for cholesterol gallstones. They are often built through apposition of layers, leading to the laminated appearance shown here. A small stone or a portion of a stone broken off may pass into the neck of the gallbladder and become impacted, or may pass down the cystic duct and impact at the ampulla. The cursors mark the thickened wall of the gallbladder, a finding consistent with chronic cholecystitis. The cholangiogram (right panel) reveals the outline of a gallstone occluding the distal dilated common bile duct near the ampulla. Most gallstones have a preponderance of cholesterol, giving them a yellow gross appearance. Some calcium bilirubinate is often present, however, and these are termed mixed stones. Stones mainly composed of calcium bilirubinate are dark-green to black and are known as pigment stones. The gallbladder on the right is dilated from obstruction by calculi at the gallbladder neck. Stones from the gallbladder, if small enough, can pass through (or impact within) the neck of the gallbladder and gain access to the common bile duct, a condition termed choledocholithiasis. In about two thirds of the population, the common bile duct joins the main pancreatic duct before emptying through the ampulla of Vater, and this allows a stone to obstruct the pancreatic duct, causing pancreatitis. The term acalculous cholecystitis applies when inflammation is present, but cholelithiasis is absent. A thickened gallbladder wall is shown here beneath the mucosa with chronic inflammatory infiltrates and containing outpouchings of the mucosa, termed RokitanskyAschoff sinuses. Bacterial infection is typically absent from cases of acute and chronic cholecystitis. Adenocarcinomas of the biliary tract are uncommon and typically occur in elderly patients. Larger tumors, or tumors arising in the extrahepatic bile ducts, may lead to biliary tract obstruction, with laboratory findings including direct hyperbilirubinemia and elevated serum alkaline phosphatase. There often are no early signs or symptoms; most adenocarcinomas of the gallbladder are nonresectable at diagnosis, and the prognosis is poor. There may be clinical signs and symptoms similar to those of cholelithiasis with cholecystitis. Adenocarcinoma of the gallbladder is more common in elderly patients and more frequently seen in women. Carcinomas can arise in the rest of the biliary tree, but these are associated with gallstones in only one third of cases and are slightly more common in men. Although liver failure is not always a consequence of cirrhosis, disruption of vascular flow leads to portal hypertension and hyperdynamic circulation. Fibrosis and even cirrhosis are reversible to some degree if the underlying disease abates. However, the extensive amounts of dark brown hemosiderin pigmentation, particularly at the periphery of the nodules, is consistent with iron overload. Microscopically they are composed of small uniform ductules with a small lumen lined by cuboidal cells. It consists of irregularly shaped and branched ductules that communicate with normal bile ducts. Polycystic liver change, if extensive, may lead to hepatic failure, but liver function is normal in most cases. The polycystin gene product is a membrane-associated protein involved in cell-cell interactions during tubular epithelial cell growth and differentiation. Ingestion of infective eggs by humans, an accidental intermediate host, is followed by hatching of oncospheres in the intestine that penetrate the intestinal wall and migrate to various tissues, often liver or lungs, where hydatid cyst development occurs over many years. The laminated cyst wall (which may calcify) is lined by a germinal epithelium from which daughter larvae develop by the thousands and float into the clear fluid. A large amebic abscess of liver is shown here, producing a mass lesion with grumous center filling much of the right lobe. Abscesses may arise in liver when there is seeding of infection from the bowel via portal circulation. Entamoeba histolytica infections can occur in situations of fecal-oral contamination, but many of these infections are mild. Dissemination of the organisms to other organs, such as the liver, is far less common. Extraintestinal manifestations of amebiasis typically appear weeks after the original colonic infection, which has often resolved. Entamoeba histolytica organisms invading the colonic mucosa gain access to the venous portal system and can be carried to the liver. Fever, right upper quadrant abdominal pain, nausea, and weight loss are typical presenting features. This parasite can have a direct life cycle with only one host, such as rodents or other omnivores. Ingested embryonated eggs hatch in the intestine, releasing larvae that migrate via the portal vein to the liver. Adult worms release eggs that remain in the liver until the host dies and eggs embryonate in a moist environment. Infarcts are uncommon because the liver has two blood supplies: portal venous system and hepatic arterial system. Hepatic infarcts typically have irregular geographic borders with surrounding hyperemia. About half of liver infarcts occur with arteritis involving the hepatic artery and its branches, such as classic polyarteritis nodosa, and the remaining half have a variety of causes. This patient had recurrent thrombosis of the inferior vena cava and hepatic venous system, leading to an enlarged liver, reduced hepatic function, and complications of portal hypertension. Causes of Budd-Chiari syndrome, which is rare, include polycythemia, pregnancy, coagulopathies, and paroxysmal nocturnal hemoglobinuria. A catheter is introduced into the jugular vein and passed down the vena cava, and the location of the hepatic veins and portal system is identified angiographically. The wire mesh stent is introduced through the liver parenchyma between large branches of the venous channels to reduce the pressure in the portal system. The use of serologic tests for syphilis coupled with widespread antibiotic therapy for Treponema pallidum infections has greatly reduced the cases of tertiary syphilis. Rarely, extensive metastases to the liver can be accompanied by a marked desmoplastic response that results in extensive fibrosis with scarring, leading to the appearance of so-called hepar lobatum carcinomatosum. Neonatal cholestasis with hepatitis may be idiopathic or the result of infection, such as cytomegalovirus, or inborn errors of metabolism. Many neonates with idiopathic or viral causes of this disease recover within several months. All these conditions are uncommon and can manifest with icterus and liver failure. Some cases represent a congenital abnormality, but most are presumed to occur after birth, possibly from viral infection. If a large enough bile duct can be found to anastomose and provide bile drainage, surgery can be curative. In contrast, nodular hyperplasia, or nodular regenerative hyperplasia, is a diffuse process distinguished from cirrhosis by the lack of portal bridging fibrosis. The pathogenesis is thought to be related to impaired blood flow causing ischemia with reactive hepatocyte proliferation. Of the pancreatic mass, 99% is acinar parenchyma producing digestive enzymes and bicarbonate, with the remainder being islets of Langerhans. The pancreas forms embryologically from a larger dorsal and smaller ventral endodermal bud from the duodenum; the buds fuse along with their respective developing ducts of Wirsung and Santorini. The pancreatic duct runs the length of the pancreas to empty into the duodenum at the ampulla of Vater. The pancreas forms embryologically from dorsal and ventral buds that form from gut outpouchings; these fuse to form the pancreas. Failure of fusion may produce pancreas divisum, with exocrine pancreatic tissue draining into the duodenum through a larger duct of Santorini and a smaller duct of Wirsung that normally forms the papilla of Vater. Much rarer is abnormal fusion of dorsal and ventral buds to form an annular pancreas that encircles the duodenum and can produce bowel obstruction. Pancreatic ectopia in gastrointestinal tract mucosa is common (2% of the population), but it is an incidental finding because the mass of tissue is typically less than 1 cm in diameter. Interspersed within the exocrine acini are the islets of Langerhans with endocrine function, one of which is shown here in the center. Small capillaries within the islet receive the hormonal secretions of islet cells (glucagon), cells (insulin), and cells (somatostatin).

The pudendal nerve (S2 to S4) and the internal pudendal artery are the major nerve and artery of the region medications every 8 hours purchase 50 mg dramamine with amex. Borders and ceiling the margin of the perineum is marked by the inferior border of the pubic symphysis at its anterior point treatment in statistics order dramamine mastercard, the tip of the coccyx at its posterior point 92507 treatment code purchase cheap dramamine on-line, and the ischial tuberosities at each of the lateral points treatment centers near me dramamine 50 mg order mastercard. The lateral margins are formed by the ischiopubic rami anteriorly and by the sacrotuberous ligaments posteriorly symptoms 0f gallbladder problems dramamine 50 mg buy otc. The perineum is divided into two triangles by an imaginary line between the two ischial tuberosities. Anterior to the line is the urogenital triangle and posterior to the line is the anal triangle. In the anatomical position, the urogenital triangle is oriented in the horizontal plane, whereas the anal triangle is tilted upward at the transtubercular line so that it faces more posteriorly. The roof of the perineum is formed mainly by the levator ani muscles that separate the pelvic cavity, above, from the perineum, below. These muscles, one on each side, form a cone- or funnel-shaped pelvic diaphragm, with the anal aperture at its inferior apex in the anal triangle. Its peripheral Pubic s ymphys is Urogenital triangle Levator ani Is chiopubic ramus Is chial tuberos ity Sacrotuberous ligament A Coccyx Anal triangle Inferior pubic ligament Urethral opening Perineal membrane Perineal body Anal aperture Vaginal opening External anal s phincter Deep Superficial Subcutaneous B External anal s phincter 244. Regional anatomy · Perineum Anteriorly, in the urogenital triangle, a U-shaped defect in the muscles, the urogenital hiatus, allows the passage of the urethra and vagina. This is best done with patients lying on their backs with their thighs exed and abducted in the lithotomy position. The ischial tuberosities are palpable on each side as large bony masses near the crease of skin (gluteal fold) between the thigh and gluteal region. The tip of the coccyx is palpable in the midline posterior to the anal aperture and marks the most posterior limit of the perineum. In men, the pubic symphysis is palpable immediately superior to where the body of the penis joins the lower abdominal wall. Imaginary lines that join the ischial tuberosities with the pubic symphysis in front, and with the tip of the coccyx behind, outline the diamond-shaped perineum. An additional line between the ischial tuberosities divides the perineum into two triangles, the urogenital triangle anteriorly and anal triangle posteriorly. This line also approximates the position of the posterior margin of the perineal membrane. The midpoint of this line marks the location of the perineal body or central tendon of the perineum. It has a free posterior border, which is anchored in the midline to the perineal body and is attached laterally to the pubic arch. Immediately superior to the perineal membrane is a thin region termed the deep perineal pouch, containing a layer of skeletal muscle and neurovascular tissues. The perineal membrane and deep perineal pouch provide support for the external genitalia, which are attached to its inferior surface. Also, the parts of the perineal membrane and deep perineal pouch inferior to the urogenital hiatus in the levator ani provide support for pelvic viscera. The urethra leaves the pelvic cavity and enters the perineum by passing through the deep perineal pouch and perineal membrane. In women, the vagina also passes through these structures posterior to the urethra. In the anal triangle, these gutters, one on each side of the anal aperture, are termed ischio-anal fossae. The medial and lateral walls converge superiorly where the levator ani muscle attaches to the fascia overlying the obturator internus muscle. The ischio-anal fossae allow movement of the pelvic diaphragm and expansion of the anal canal during defecation. The ischio-anal fossae of the anal triangle are continuous anteriorly with recesses that project into the urogenital triangle superior to the deep perineal pouch. Clinical app Abscesses in the ischio-anal fossae the anal mucosa is particularly vulnerable to injury and may be easily torn by hard feces. Occasionally, patients develop in ammation and infection of the anal canal (sinuses or crypts), which can spread laterally into the ischio-anal fossae or superiorly into the pelvic cavity. The ceiling of the anal triangle is the pelvic diaphragm, which is formed by the levator ani and coccygeus muscles. The anal aperture occurs centrally in the anal triangle and is related on either side to an ischio-anal fossa. The external anal sphincter, which surrounds the anal canal, is formed by skeletal muscle and consists of three parts-deep, super cial, and subcutaneous- arranged sequentially along the canal from superior to inferior (Table 5. The external anal sphincter is innervated by inferior rectal branches of the pudendal nerve and by branches directly from the anterior ramus of S4. Bulbourethral gland within d eep pouch Urogenital triangle the urogenital triangle of the perineum is the anterior half of the perineum and is oriented in the horizontal plane. Surrounds lower part of anal canal Horizontally attened disc that surrounds the anal aperture just beneath the skin. Anchored anteriorly to the perineal body and posteriorly to the anococcygeal body Pudendal nerve (S2 and S3) and branches directly from S4 Muscles of pelvic wall External anal sphincter Deep part Super cial part Subcutaneous part 246 Regional anatomy · Perineum As with the anal triangle, the roof or ceiling of the urogenital triangle is the levator ani muscle. Unlike the anal triangle, the urogenital triangle contains a strong bromuscular support platform, the perineal membrane, and deep perineal pouch (see p. Anterior extensions of the ischio-anal fossae occur between the deep perineal pouch and the levator ani muscle on each side. Between the perineal membrane and the membranous layer of super cial fascia is the super cial perineal pouch. The principal structures in this pouch are the erectile tissues of the penis and clitoris and associated skeletal muscles. Unlike the root of penis, the root of clitoris technically consists only of the two crura. The body of clitoris is supported by a suspensory ligament that attaches superiorly to the pubic symphysis. The glans clitoris is attached to the distal end of the body and is connected to the bulbs of the vestibule by small bands of erectile tissue. The glans clitoris is exposed in the perineum and the body of the clitoris can be palpated through skin. Structures in the super cial perineal pouch the super cial perineal pouch contains. Each erectile structure consists of a central core of expandable vascular tissue and its surrounding connective tissue capsule. Erectile tissues Two sets of erectile structures join to form the penis and the clitoris. A pair of cylindrically shaped corpora cavernosa, one on each side of the urogenital triangle, are anchored by their proximal ends to the pubic arch. These attached parts are often termed the crura (from the Latin for "legs") of the clitoris or the penis. The distal ends of the corpora, which are not attached to bone, form the body of the clitoris in women and the dorsal parts of the body of the penis in men. The second set of erectile tissues surrounds the openings of the urogenital system. In women, a pair of erectile structures, termed the bulbs of vestibule, are situated one on each side at the vaginal opening and are rmly anchored to the perineal membrane. Small bands of erectile tissues connect the anterior ends of these bulbs to a single, small, pea-shaped erectile mass, the glans clitoris, which is positioned in the midline at the end of the body of the clitoris and anterior to the opening of the urethra. In men, a single large erectile mass, the corpus spongiosum, is the structural equivalent to the bulbs of the vestibule, the glans clitoris, and the interconnecting bands of erectile tissues in women. The corpus spongiosum is anchored at its base (bulb of penis) to the perineal membrane. Its proximal end, which is not attached, forms the ventral part of the body of the penis and expands over the end of the body of the penis to form the glans penis. In men, the urethra is enclosed by the corpus spongiosum and opens at the end of the penis. This is unlike the situation in women where the urethra is not enclosed by erectile tissue of the clitoris and opens directly into the vestibule of the perineum. Penis the penis is composed mainly of the two corpora cavernosa and the single corpus spongiosum, which contains the urethra. The body of penis, which is covered entirely by skin, is formed by the tethering of the two proximal free parts of the corpora cavernosa and the related free part of the corpus spongiosum. The base of the body of penis is supported by two ligaments: the suspensory ligament of penis (attached superiorly to the pubic symphysis), and the more super cially positioned fundiform ligament of penis (attached above to the linea alba of the anterior abdominal wall and splits below into two bands that pass on each side of the penis and unite inferiorly). Because the anatomical position of the penis is erect, the paired corpora are de ned as dorsal in the body of the penis and the single corpus spongiosum as ventral, even though the positions are reversed in the nonerect (accid) penis. The corpus spongiosum expands to form the head of penis (glans penis) over the distal ends of the corpora cavernosa. Erection Erection of the penis and clitoris is a vascular event generated by parasympathetic bers carried in pelvic splanchnic nerves from the anterior rami of S2 to S4, which enter the inferior hypogastric part of the prevertebral plexus and ultimately pass through the deep perineal pouch and perineal membrane to innervate the erectile tissues. Stimulation of these nerves causes speci c arteries in the erectile tissues to relax. This allows blood to ll the tissues, causing the penis and clitoris to become erect. They are small, pea-shaped mucous glands that lie posterior to the bulbs of the vestibule on each side of the vaginal opening and are the female homologues of the bulbourethral glands in men. However, the bulbourethral glands are located within the deep perineal pouch, whereas the greater vestibular glands are in the super cial perineal pouch. The duct of each greater vestibular gland opens into the vestibule of the perineum along the posterolateral margin of the vaginal opening. Like the bulbourethral glands in men, the greater vestibular glands produce secretion during sexual arousal. Muscles the super cial perineal pouch contains three pairs of muscles: the ischiocavernosus, bulbospongiosus, and super cial transverse perineal muscles (Table 5. Two of these three pairs of muscles are associated with the roots of the penis and clitoris; the other pair is associated with the perineal body. Surface anatomy Super cial features of the external genitalia in women In women, the clitoris and vestibular apparatus, together with a number of skin and tissue folds, form the vulva. The region enclosed between them, and into which the urethra and vagina open, is the vestibule. The medial folds unite to form the frenulum of clitoris, that joins the glans clitoris. The lateral folds unite ventrally over the glans clitoris and the body of clitoris to form the prepuce of clitoris (hood). The body of the clitoris extends anteriorly from the glans clitoris and is palpable deep to the prepuce and related skin. Posterior to the vestibule, the labia minora unite, forming a small transverse fold, the frenulum of labia minora (the fourchette). Within the vestibule, the vaginal ori ce is surrounded to varying degrees by a ringlike fold of membrane, the hymen, which may have a small central perforation or may completely close the vaginal opening. Following rupture of the hymen (resulting from rst sexual intercourse or injury), irregular remnants of the hymen fringe the vaginal opening. The ori ces of the urethra and the vagina are associated with the openings of glands. Regional anatomy · Perineum 5 crease between the vaginal ori ce and remnants of the hymen. Lateral to the labia minora are two broad folds, the labia majora, which unite anteriorly to form the mons pubis. The mons pubis overlies the inferior aspect of the pubic symphysis and is anterior to the vestibule and the clitoris. Posteriorly, the labia majora do not unite and are separated by a depression termed the posterior commissure, which overlies the position of the perineal body. A recess or gutter, termed the fornix, occurs between the cervix and the vaginal wall and is further subdivided, based on location, into anterior, posterior, and lateral fornices. The roots of the clitoris occur deep to surface features of the perineum and are Skin overlying body of clitoris Glans clitoris Labium minus Ves tibule Labium majus Pos terior commis s ure B (overlies Vaginal opening perineal (introitus) body) attached to the ischiopubic rami and the perineal membrane. These erectile masses are continuous, via thin bands of erectile tissues, with the glans clitoris, which is visible under the clitoral hood. The greater vestibular glands occur posterior to the bulbs of the vestibule on either side of the vaginal ori ce. Anteriorly, these erectile corpora detach from bone, curve posteroinferiorly, and unite to form the body of the clitoris. The body of clitoris underlies the ridge of skin immediately anterior to the clitoral hood (prepuce). Inferior view of the urogenital triangle of a woman with major features indicated. Also indicated are the glans clitoris, the clitoral hood, and the frenulum of the clitoris. Inferior view of the vestibule showing the urethral and vaginal ori ces and the hymen. Inferior view of the vestibule with the left labium minus pulled to the side to show the regions of the vestibule into which the greater vestibular and para-urethral glands open. Inferior view of the urogenital triangle of a woman with the erectile tissues of the clitoris and vestibule and the greater vestibular glands indicated with overlays. The urogenital triangle itself contains the root of the penis; however, the testes and associated structures, although they migrate into the scrotum from the abdomen, are generally evaluated with the penis during a physical examination.

Occasionally the clot may dislodge and pass into the venous system through the right side of the heart and into the main pulmonary arteries medicine grand rounds dramamine 50 mg buy without prescription. If the clots are of signi cant size they obstruct blood ow to the lung and may produce instantaneous death treatment spinal stenosis purchase dramamine discount. Other complications include destruction of the normal valvular system in the legs symptoms when quitting smoking generic dramamine 50 mg buy on-line, which may lead to venous incompetency and chronic leg swelling with ulceration medications look up purchase discount dramamine line. In certain situations it is not possible to optimize the patient with prophylactic treatment symptoms 7dpiui 50 mg dramamine purchase with visa, and it may be necessary to insert a lter into the inferior vena cava that traps any large clots. Surface anatomy Visualizing the position of major blood vessels Each of the vertebral levels in the abdomen is related to the origin of major blood vessels. Lymphatic system Lymphatic drainage from most deep structures and regions of the body below the diaphragm converges mainly on collections of lymph nodes and vessels associated with the major blood vessels of the posterior abdominal region. Pre-aortic and lateral aortic or lumbar nodes (para-aortic nodes) Approaching the aortic bifurcation, the collections of lymphatics associated with the two common iliac arteries and veins merge, and multiple groups of lymphatic vessels and nodes associated with the abdominal aorta and inferior vena cava pass superiorly. These collections may be subdivided into pre-aortic nodes, which are anterior to the abdominal aorta, and right and left lateral aortic or lumbar nodes (para-aortic nodes), which are positioned on either side of the abdominal aorta (Table 4. The lateral aortic or lumbar lymph nodes (para-aortic nodes) receive lymphatics from the body wall, the kidneys, the suprarenal glands, and the testes or ovaries. The pre-aortic nodes are organized around the three anterior branches of the abdominal aorta that supply the abdominal part of the gastrointestinal tract, as well as the spleen, pancreas, gallbladder, and liver. They are divided into celiac, superior mesenteric, and inferior mesenteric nodes, and receive lymph from the organs supplied by the similarly named arteries. Finally, the lateral aortic or lumbar nodes form the right and left lumbar trunks, whereas the pre-aortic nodes form the intestinal trunk. These trunks come together and form a con uence that, at times, appears as a saccular dilation (the cisterna chyli). Lymphatic vessel Right jugular trunk Left jugular trunk Right subclavian trunk Left subclavian trunk Right bronchomediastinal trunk Left bronchomediastinal trunk Area drained Right side of head and neck Left side of head and neck Right upper limb, super cial regions of thoracic and upper abdominal wall Left upper limb, super cial regions of thoracic and upper abdominal wall Right lung and bronchi, mediastinal structures, thoracic wall Left lung and bronchi, mediastinal structures, thoracic wall Lower limbs, abdominal walls and viscera, pelvic walls and viscera, thoracic wall 200 Thoracic duct Regional anatomy · Posterior abdominal region 4 Clinical app Retroperitoneal lymph node surgery From a clinical perspective, retroperitoneal lymph nodes are arranged in two groups. The pre-aortic lymph node group drains lymph from the embryological midline structures, such as the liver, bowel, and pancreas. The para-aortic lymph node group (the lateral aortic or lumbar nodes), on either side of the aorta, drain lymph from bilateral structures, such as the kidneys and adrenal glands. Organs embryologically derived from the posterior abdominal wall also drain lymph to these nodes. These organs include the ovaries and the testes (importantly, the testes do not drain lymph to the inguinal regions). Massively enlarged lymph nodes are a feature of lymphoma, and smaller lymph node enlargement is observed in the presence of infection and metastatic malignant spread of disease. The surgical approach to retroperitoneal lymph node resection involves a lateral paramedian incision in the midclavicular line. The three layers of the anterolateral abdominal wall (external oblique, internal oblique, and transversus abdominis) are opened and the transversalis fascia is divided. Instead of entering the parietal peritoneum, which is standard procedure for most intra-abdominal surgical operations, the surgeon gently pushes the parietal peritoneum toward the midline, which moves the intra-abdominal contents and allows a clear view of the retroperitoneal structures. On the left, the para-aortic lymph node group (lateral aortic or lumbar nodes) are easily demonstrated with a clear view of the abdominal aorta and kidney. On the right the inferior vena cava is demonstrated, which has to be retracted to access to the right para-aortic lymph node chain (lateral aortic or lumbar nodes). The procedure of the retroperitoneal lymph node dissection is extremely well tolerated and lacks the problems of entering the peritoneal cavity. Unfortunately, the complication of a vertical incision in the midclavicular line is to divide the segmental nerve supply to the rectus abdominis muscle. This produces muscle atrophy and asymmetrical proportions to the anterior abdominal wall. Sympathetic trunks and splanchnic nerves the sympathetic trunks pass through the posterior abdominal region anterolateral to the lumbar vertebral bodies, before continuing across the sacral promontory and into the pelvic cavity. These represent collections of neuronal cell bodies-primarily postganglionic neuronal cell bodies-which are located outside the central nervous system. There are usually four ganglia along the sympathetic trunks in the posterior abdominal (lumbar) region. Also associated with the sympathetic trunks in the posterior abdominal region are the lumbar splanchnic nerves. These components of the nervous system pass from the sympathetic trunks to the plexus of nerves and ganglia associated with the abdominal aorta. Usually two to four lumbar splanchnic nerves carry preganglionic sympathetic bers and visceral afferent bers. Abdominal prevertebral plexus and ganglia the abdominal prevertebral plexus is a network of nerve bers surrounding the abdominal aorta. It extends from the aortic hiatus of the diaphragm to the bifurcation of the aorta into the right and left common iliac arteries. Continuing inferiorly, the plexus of nerve bers extending from just below the superior mesenteric artery to the aortic bifurcation is the abdominal aortic plexus. At the bifurcation of the abdominal aorta, the abdominal prevertebral plexus continues inferiorly as the superior hypogastric plexus. Throughout its length, the abdominal prevertebral plexus is a conduit for: preganglionic sympathetic and visceral afferent bers from the thoracic and lumbar splanchnic nerves. Associated with the abdominal prevertebral plexus are clumps of nervous tissue (the prevertebral ganglia), which are collections of postganglionic sympathetic neuronal cell bodies in recognizable aggregations along the abdominal prevertebral plexus; they are usually named after the nearest branch of the abdominal aorta. They are therefore referred to as celiac, superior mesenteric, aorticorenal, and inferior mesenteric ganglia. These structures, along with the abdominal prevertebral plexus, play a critical role in the innervation of the abdominal viscera. Nervous system in the posterior abdominal region Several important components of the nervous system are in the posterior abdominal region. These include the sympathetic trunks and associated splanchnic nerves, the plexus of nerves and ganglia associated with the abdominal aorta, and the lumbar plexus of nerves. Pos terior root Anterior root Es ophagus Vagus nerve Aorta Celiac ganglion Preganglionic paras ympathetic Enteric neuron Gray ramus communicans Pos terior and anterior rami White ramus communicans Sympathetic ganglion and trunk Greater s planchnic nerve Vis ceral afferent Vis ceral afferent Preganglionic s ympathetic Pos tganglionic s ympathetic 202. Lumbar plexus the lumbar plexus is formed by the anterior rami of nerves L1 to L3, and most of the anterior ramus of L4 (Table 4. Branches of the lumbar plexus include the iliohypogastric, ilio-inguinal, genitofemoral, lateral cutaneous nerve of thigh (lateral femoral cutaneous), femoral, and obturator nerves. The lumbar plexus forms in the substance of the psoas major muscle anterior to its attachment to the transverse processes of the lumbar vertebrae. Therefore, relative to the psoas major muscle, the various branches emerge either: anterior-genitofemoral nerve, medial-obturator nerve, or lateral-iliohypogastric, ilio-inguinal, and femoral nerves, and the lateral cutaneous nerve of the thigh. The sacrotuberous ligament is also triangular and is super cial to the sacrospinous ligament. Its base has a broad attachment that extends from the posterior superior iliac spine of the pelvic bone, along the dorsal aspect and the lateral margin of the sacrum, and onto the dorsolateral surface of the coccyx. Laterally, the apex of the ligament is attached to the medial margin of the ischial tuberosity. These ligaments stabilize the sacrum on the pelvic bones by resisting the upward tilting of the inferior aspect of the sacrum. They also convert the greater and lesser sciatic notches of the pelvic bone into foramina. The greater sciatic foramen lies superior to the sacrospinous ligament and the ischial spine. The lesser sciatic foramen lies inferior to the ischial spine and sacrospinous ligament between the sacrospinous and sacrotuberous ligaments. The muscle bers of the obturator internus converge to form a tendon that leaves the pelvic cavity through the lesser sciatic foramen, makes a 90° bend around the ischium between the ischial spine and ischial tuberosity, and then passes posterior to the hip joint to reach its insertion Anterior surface of sacrum between anterior sacral foramina Insertion Medial surface of greater trochanter of femur Innervation Nerve to obturator internus L5, S1 Function Lateral rotation of the extended hip joint; abduction of exed hip Piriformis 214 Medial side of superior border of greater trochanter of femur Branches from L5, S1, and S2 Lateral rotation of the extended hip joint; abduction of exed hip Regional anatomy · Pelvis Muscles of the pelvic w all 5 Two muscles, the obturator internus and the piriformis, contribute to the lateral walls of the pelvic cavity. These muscles originate in the pelvic cavity but attach peripherally to the femur (Table 5. Apertures in the pelvic w all Passing through the foramen below the piriformis are the inferior gluteal nerves and vessels, the sciatic nerve, the pudendal nerve, the internal pudendal vessels, the posterior femoral cutaneous nerves, and the nerves to the obturator internus and quadratus femoris muscles. Each lateral pelvic wall has three major apertures through which structures pass between the pelvic cavity and other regions. Obturator canal At the top of the obturator foramen is the obturator canal, which is bordered by the obturator membrane, the associated obturator muscles, and the superior pubic ramus. The obturator nerve and vessels pass from the pelvic cavity to the thigh through this canal. Greater sciatic foramen the greater sciatic foramen is a major route of communication between the pelvic cavity and the lower limb. It is formed by the greater sciatic notch in the pelvic bone, the sacrotuberous and the sacrospinous ligaments, and the spine of the ischium. The piriformis muscle passes through the greater sciatic foramen, dividing it into two parts. The superior gluteal nerves and vessels pass through the foramen above the piriformis. Lesser sciatic foramen the lesser sciatic foramen is formed by the lesser sciatic notch of the pelvic bone, the ischial spine, the sacrospinous ligament, and the sacrotuberous ligament. The tendon of the obturator internus muscle passes through this foramen to enter the gluteal region of the lower limb. Because the lesser sciatic foramen is positioned below the attachment of the pelvic oor, it acts as a route of communication between the perineum and the gluteal region. The pudendal nerve and internal pudendal vessels pass between the pelvic cavity (above the pelvic oor) and the perineum (below the pelvic oor), by rst passing out of the pelvic cavity through the greater sciatic foramen, then looping around the ischial spine and sacrospinous ligament to pass through the lesser sciatic foramen to enter the perineum. Pelvic outlet the pelvic outlet is diamond shaped, with the anterior part of the diamond de ned predominantly by bone and the posterior part mainly by ligaments. In the midline anteriorly, the boundary of the pelvic outlet is the pubic symphysis. Reinforces the external anal sphincter and, in women, functions as a vaginal sphincter Contributes to the formation of the pelvic oor, which supports the pelvic viscera; pulls the coccyx forward after defecation Coccygeus Branches from the anterior rami of S3 and S4 Pubic s ymphys is Pubic arch Body of pubis the area enclosed by the boundaries of the pelvic outlet and below the pelvic oor is the perineum. Pelvic oor the pelvic oor is formed by the pelvic diaphragm and, in the anterior midline, the perineal membrane and the muscles in the deep perineal pouch. The pelvic diaphragm is formed by the levator ani and the coccygeus muscles from both sides. Extending laterally and posteriorly, the boundary on each side is the inferior border of the body of the pubis, the inferior ramus of the pubis, the ramus of the ischium, and the ischial tuberosity. From the ischial tuberosities, the boundaries continue posteriorly and medially along the sacrotuberous ligament on both sides to the coccyx. Terminal parts of the urinary and gastrointestinal tracts and the vagina pass through the pelvic outlet. Shaped like a bowl or funnel and attached superiorly to the pelvic walls, it consists of the levator ani and the coccygeus muscles (Table 5. Thus: the greater sciatic foramen is situated above the level of the pelvic oor and is a route of communication between the pelvic cavity and the gluteal region of the lower limb; and the lesser sciatic foramen is situated below the pelvic oor, providing a route of communication between the gluteal region of the lower limb and the perineum. These measurements include: the sagittal inlet (between the promontory and the top of the pubic symphysis); the maximum transverse diameter of the inlet; the bispinous outlet (the distance between ischial spines); and the sagittal outlet (the distance between the tip of the coccyx and the inferior margin of the pubic symphysis). Levator ani the two levator ani muscles originate from each side of the pelvic wall, course medially and inferiorly, and join together in the midline. The attachment to the pelvic wall follows the circular contour of the wall and includes. At the midline, the muscles blend together posterior to the vagina in women and around the anal aperture in both sexes. Posterior to the anal aperture, the muscles come together as a ligament or raphe called the anococcygeal ligament (anococcygeal body) and attaches to the coccyx. Anteriorly, the muscles are separated by a U-shaped defect or gap termed the urogenital hiatus. The margins of this hiatus merge with the walls of the associated viscera and with muscles in the deep perineal pouch below. The hiatus allows the urethra (in both men and women), and the vagina (in women), to pass through the pelvic diaphragm. The levator ani muscles are divided into at least three collections of muscle bers, based on site of origin and relationship to viscera in the midline: the pubococcygeus, the puborectalis, and the iliococcygeus muscles. The pubococcygeus originates from the body of the pubis and courses posteriorly to attach along the midline as far back as the coccyx. This part of the muscle is further subdivided on the basis of association with structures in the midline into the puboprostaticus (levator prostatae), the pubovaginalis, and the puboanalis muscles. A second major collection of muscle bers, the puborectalis portion of the levator ani muscles, originates, in association with the pubococcygeus muscle, from the pubis and passes inferiorly on each side to form a sling around the terminal part of the gastrointestinal tract. This muscular sling maintains an angle or exure, called the perineal exure, at the anorectal junction. This angle functions as part of the mechanism that keeps the end of the gastrointestinal system closed. This part of the muscle originates from the fascia that covers the obturator internus muscle. It joins the same muscle on the other side in the midline to form a ligament or raphe that extends from the anal aperture to the coccyx. The levator ani muscles help support the pelvic viscera and maintain closure of the rectum and vagina. Clinical app Defecation At the beginning of defecation, closure of the larynx stabilizes the diaphragm and intra-abdominal pressure is increased by contraction of abdominal wall muscles. As defecation proceeds, the puborectalis muscle surrounding the anorectal junction relaxes, which straightens the anorectal angle.

Each kidney has a smooth anterior and posterior surface covered by a brous capsule 10 medications generic dramamine 50 mg on line, which is easily removable except during disease medicine etodolac buy 50 mg dramamine with mastercard. On the medial margin of each kidney is the hilum of kidney treatment 1 degree burn order dramamine 50 mg with mastercard, which is a deep vertical slit through which renal vessels medications ranitidine cheap 50 mg dramamine visa, lymphatics treatment diverticulitis buy dramamine no prescription, and nerves enter and leave the substance of the kidney. The renal cortex is a continuous band of pale tissue that completely surrounds the renal medulla. Extensions of the renal cortex (the renal columns) project into the inner aspect of the kidney, dividing the renal medulla into discontinuous aggregations of triangular-shaped tissue (the renal pyramids). The bases of the renal pyramids are directed outward, toward the renal cortex, whereas the apex of each renal pyramid projects inward, toward the renal sinus. The apical projection (renal papilla) contains the openings of the papillary ducts draining the renal tubules and is surrounded by a minor calyx. The minor calices receive urine from the papillary ducts and represent the proximal parts of the tube that will eventually form the ureter. In the renal sinus, several minor calices unite to form a major calyx, and two or three major calices unite to form the renal pelvis, which is the funnel-shaped superior end of the ureters. Regional anatomy · Posterior abdominal region iliac or the beginning of the external iliac arteries, enter the pelvic cavity, and continue their journey to the bladder. Renal vasculature and lymphatics A single large renal artery, a lateral branch of the abdominal aorta, supplies each kidney. The left renal artery usually arises a little higher than the right, and the right renal artery is longer and passes posterior to the inferior vena cava. As each renal artery approaches the renal hilum, it divides into anterior and posterior branches, which supply the renal parenchyma. They originate from the lateral aspect of the abdominal aorta, either above or below the primary renal arteries, enter the hilum with the primary arteries or pass directly into the kidney at some other level, and are commonly called extrahilar arteries. Multiple renal veins contribute to the formation of the left and right renal veins, both of which are anterior to the renal arteries. Importantly, the longer left renal vein crosses the midline anterior to the abdominal aorta and posterior to the superior mesenteric artery and can be compressed by an aneurysm in either of these two vessels. The lymphatic drainage of each kidney is to the lateral aortic (lumbar) nodes around the origin of the renal artery. The ureters receive arterial branches from adjacent vessels as they pass toward the bladder. The middle part may receive branches from the abdominal aorta, the testicular or ovarian arteries, and the common iliac arteries. In the pelvic cavity, the ureters are supplied by one or more arteries from branches of the internal iliac arteries. In all cases, arteries reaching the ureters divide into ascending and descending branches, which form longitudinal anastomoses. Lymphatic drainage of the ureters follows a pattern similar to that of the arterial supply. They are continuous superiorly with the renal pelvis, which is a funnel-shaped structure in the renal sinus. The renal pelvis is formed from a condensation of two or three major calices, which in turn are formed by the condensation of several minor calices. The renal pelvis narrows as it passes inferiorly through the hilum of the kidney and becomes continuous with the ureter at the ureteropelvic junction. Inferior to this junction, the ureters descend retroperitoneally on the medial aspect of the psoas major muscle. At the pelvic brim, the ureters cross either the end of the common External iliac artery. The inferior part of each ureter drains to lymph nodes associated with the external and internal iliac vessels. Clinical app Kidney transplant Kidney transplantation began in the United States in the 1950s. Since the rst transplant, the major problem for kidney transplantation has been tissue rejection. A number of years have passed since this initial procedure and there have been signi cant breakthroughs in transplant rejection medicine. Renal transplantation is now a common procedure undertaken in patients with end-stage renal failure. An ideal place to situate the transplant kidney is in the left or the right iliac fossa. The external oblique muscle, internal oblique muscle, transverse abdominis muscle, and transversalis fascia are divided. The surgeon identi es the parietal peritoneum but does not enter the peritoneal cavity. The parietal peritoneum is medially retracted to reveal the external iliac artery, external iliac vein, and the bladder. In some instances the internal iliac artery of the recipient is mobilized and anastomosed directly as an end-to-end procedure onto the renal artery of the donor kidney. The ureter is easily tunneled obliquely through the bladder wall with a straightforward anastomosis. The left and right iliac fossae are ideal locations for the transplant kidney, because a new space can be created without compromise to other structures. Ureteric innervation Ureteric innervation is from the renal, aortic, superior hypogastric, and inferior hypogastric plexuses through nerves that follow the blood vessels. Visceral efferent bers come from both sympathetic and parasympathetic sources, whereas visceral afferent bers return to T11 to L2 spinal cord levels. Ureteric pain, which is usually related to distention of the ureter, is therefore referred to cutaneous areas supplied by T11 to L2 spinal cord levels. These areas would most likely include the posterior and lateral abdominal wall below the ribs and above the iliac crest, the pubic region, the scrotum in males, the labia majora in females, and the proximal anterior aspect of the thigh. Clinical app Urinary tract stones Urinary tract stones (calculi) occur more frequently in men than in women, are most common in people aged between 20 and 60 years, and are usually associated with sedentary lifestyles. The stones are polycrystalline aggregates of calcium, phosphate, oxalate, urate, and other soluble salts within an organic matrix. The urine becomes saturated with these salts, and small variations in the pH cause the salts to precipitate. Typically the patient has pain that radiates from the infrascapular region (loin) into the groin, and even into the scrotum or labia majora. Bla dde r Clinical app Urinary tract cancer Most tumors that arise in the kidney are renal cell carcinomas. Approximately 5% of tumors within the kidney are transitional cell tumors, which arise from the urothelium of the renal pelvis. Most patients typically have blood in the urine (hematuria), pain in the infrascapular region (loin), and a mass. Renal cell tumors are unusual because not only do they grow outward from the kidney, invading the fat and fascia, but they also spread into the renal vein. This venous extension is rare for any other type of tumor, so when seen, renal cell carcinoma should be suspected. The urothelium is present from the calices to the urethra and behaves as a "single unit. The relatively high atomic number of iodine compared with the atomic number of carbon, hydrogen, and oxygen, attenuates the radiation beam. After intravenous injection, contrast media are excreted predominantly by glomerular ltration, although some are secreted by the renal tubules. This allows visualization of the collecting system as well as the ureters and bladder. Although the ureters are poorly visualized using ultrasound, the bladder can be easily seen when full. Ultrasound measurements of bladder volume can be obtained before and after micturition. B Right kidne y Re na l pe lvis Le ft kidne y Nuclear medicine Nuclear medicine is an extremely useful tool for investigating the urinary tract, because radioisotope compounds can be used to estimate renal cell mass and function, and assess the parenchyma for renal scarring. These tests are often very useful in children when renal scarring and re ux disease is suspected. Suprarenal glands the suprarenal glands are associated with the superior pole of each kidney. The right gland is shaped like a pyramid, whereas the left gland is semilunar in shape and the larger of the two. Anterior to the right suprarenal gland is part of the right lobe of the liver and the inferior vena cava, whereas anterior to the left suprarenal gland is part of the stomach, pancreas, and, on occasion, the spleen. The suprarenal glands are surrounded by the perinephric fat and enclosed in the renal fascia, although a thin septum separates each gland from its associated kidney. Right s uprarenal gland Left s uprarenal gland Middle s uprarenal artery Inferior s uprarenal artery Abdominal aorta Right kidney Inferior vena cava Left kidney Suprarenal vasculature. The arterial supply to the suprarenal glands is extensive and arises from three primary sources. A middle branch (middle suprarenal artery) to the suprarenal glands usually arises directly from the abdominal aorta. Inferior branches (inferior suprarenal arteries) from the renal arteries pass upward to the suprarenal glands. In contrast to this multiple arterial supply is the venous drainage, which usually consists of a single vein leaving the hilum of each gland. On the right side, the right suprarenal vein is short and almost immediately enters the inferior vena cava; whereas on the left side, the left suprarenal vein passes inferiorly to enter the left renal vein. Suprarenal Innervation the suprarenal gland is mainly innervated by preganglionic sympathetic bers from spinal levels T8-L1 that pass through both the sympathetic trunk and the prevertebral plexus without synapsing. This bifurcation can be visualized on the anterior abdominal wall at a point approximately 2. As the abdominal aorta passes through the posterior abdominal region, the prevertebral plexus of nerves and ganglia covers its anterior surface. It is also related to numerous other structures: Anterior to the abdominal aorta, as it descends, are the pancreas and splenic vein, the left renal vein, and the inferior part of the duodenum. On its right side are the cisterna chyli, thoracic duct, azygos vein, right crus of the diaphragm, and the inferior vena cava. Vasculature Abdominal aorta the abdominal aorta begins at the aortic hiatus of the diaphragm as a midline structure at approximately the Inferior phrenic arteries Diaphragm Celiac trunk Middle s uprarenal artery Middle s uprarenal artery Left renal artery Superior mes enteric artery Tes ticular or ovarian arteries Lumbar arteries Inferior mes enteric artery Common iliac artery Ps oas major mus cle Median s acral artery 196. The three unpaired visceral branches that arise from the anterior surface of the abdominal aorta (Table 4. They run laterally and posteriorly over the bodies of the lumbar vertebrae, continue laterally, passing posterior to the sympathetic trunks and between the transverse processes of adjacent lumbar vertebrae, and reach the abdominal wall. From this point onward, they demonstrate a branching pattern similar to a posterior intercostal artery, which includes providing segmental branches that supply the spinal cord. This vessel arises from the posterior surface of the abdominal aorta just superior to the bifurcation and passes in an inferior direction, rst over the anterior surface of the lower lumbar vertebrae and then over the anterior surface of the sacrum and coccyx. Clinical app Abdominal aortic stent graft An abdominal aortic aneurysm is a dilatation of the aorta and generally tends to occur in the infrarenal region (the region at or below the renal arteries). As the aorta expands, the risk of rupture increases, and it is now generally accepted that when an aneurysm reaches 5. Treatment of aneurysms prior to rupture can involve inserting an endovascular graft. The technique involves surgically dissecting the femoral artery below the inguinal ligament. A small incision is made in the femoral artery and the preloaded compressed graft with metal support struts is passed on a large catheter into the abdominal aorta through the femoral artery. Using X-ray for guidance the graft is opened so that it lines the inside of the aorta. Posterior branches the posterior branches of the abdominal aorta are vessels supplying the diaphragm or body wall and are (Table 4. Whatever their origin, they pass upward, provide some arterial supply to the suprarenal gland, and continue onto the inferior surface of the diaphragm. Tributaries to the inferior vena cava include the: common iliac veins, lumbar veins, right testicular or ovarian vein, renal veins, right suprarenal vein, inferior phrenic veins, and hepatic veins. There are no tributaries from the abdominal part of the gastrointestinal tract, the spleen, the pancreas, or the gallbladder, because veins from these structures are components of the portal venous system, which rst passes through the liver. Of the venous tributaries mentioned above, the lumbar veins are unique in their connections and deserve special attention. Not all of the lumbar veins drain directly into the inferior vena cava: the fth lumbar vein generally drains into the iliolumbar vein, a tributary of the common iliac vein. Note the images only demonstrate the intraluminal contrast and not the entire vessel. Hepatic veins Es ophagus Inferior vena cava Left kidney Left renal vein Right tes ticular or ovarian vein Right kidney Inferior vena cava the inferior vena cava returns blood from all structures below the diaphragm to the right atrium of the heart. It ascends through the posterior abdominal region anterior to the vertebral column immediately to the right of the abdominal aorta. During its course, the anterior surface of the inferior vena cava is crossed by the right common iliac artery, the root of the mesentery, the right testicular or ovarian Abdominal aorta Right external iliac artery and vein Left external iliac artery and vein Left femoral artery and vein Right femoral artery and vein 198. Regional anatomy · Posterior abdominal region the ascending lumbar veins are long, anastomosing venous channels that connect the common iliac, iliolumbar, and lumbar veins with the azygos and hemiazygos veins of the thorax. If the inferior vena cava becomes blocked, the ascending lumbar veins become important collateral channels between the lower and upper parts of the body. Common predisposing factors include hospitalization, surgery, oral contraceptives, smoking, and air travel. The diagnosis of deep vein thrombosis may be dif cult to establish, with symptoms including leg swelling and pain and discomfort in the calf. Both the internal and the external anal sphincters also relax to allow feces to move through the anal canal. Normally, the puborectal sling maintains an angle of about 90° between the rectum and the anal canal and acts as a "pinch valve" to prevent defecation.

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