Anatomy of abdomen and regions of trunk

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1. Regions of abdominal For the purpose of description clinicians use planes to refer nine regions of the abdominal cavity to describing the location of the organs They use four planes two horizontal and two vertical T he nine regiona are:

2. Regions and their contents Right Hypochondriac Epigastric Left Hypochondriac Digestive:      Liver      Gall Bladder      Small Intestine      Ascending Colon      Transverse Colon Endocrine:      Right Kidney Excretory:      Right Kidney Lymphatic:      NONE Reproductive:      Digestive:       Esophagus      Stomach      Liver      Pancreas      Small Intestine      Transverse Colon Endocrine:      Right & Left Adrenal Glands      Pancreas      Right & Left Kidneys Excretory:      Right & Left Kidneys      Right & Left Ureters Lymphatic:      Spleen Reproductive:      NONE Digestive:      Stomach      Liver (tip)      Pancreas (tail of)      Small Intestine      Transverse Colon      Descending Colon Endocrine:      Pancreas      Left Kidney Excretory:      Left Kidney Lymphatic:      Spleen Reproductive:      NONE

3. Right lumber umbilicus Left lumber Digestive:      Liver (tip)      Gall Bladder      Small Intestine      Ascending Colon Endocrine:      Right Kidney Excretory:      Right Kidney Lymphatic:      NONE Reproductive:      NONE Digestive:      Stomach      Pancreas      Small Intestine      Transverse Colon Endocrine:      Pancreas      Right & Left Kidneys Excretory:      Right & Left Kidneys      Right & Left Ureters Lymphatic:      Cisterna chyli Reproductive:      NONE Digestive:      Small Intestine      Descending Colon Endocrine:      Left Kidney (tip) Excretory:      Left Kidney (tip) Lymphatic:      NONE Reproductive:      NONE

4. Right iliac hypo gastric Left iliac Digestive:      Small Intestine      Appendix      Cecum & Ascending Colon Endocrine:      Right Ovary (Females) Excretory:      NONE Lymphatic:      NONE Reproductive:      Female -           Right Ovary           Right Fallopian Tube      Male -           NONE Digestive:      Small Intestine      Sigmoid Colon      Rectum Endocrine:           Right & Left Ovaries (Fem.) Excretory:      Right & Left Ureters      Urinary Bladder Lymphatic:      NONE Reproductive:      Female -           Uterus *           Right & Left Ovaries           Right & Left Fallopian Tubes      Male -           Vas Deferens           Seminal Vessicle           Prostate Digestive:      Small Intestine      Descending Colon      Sigmoid Colon Endocrine:      Right Ovary (Females) Excretory:      NONE Lymphatic:      NONE Reproductive:      Female -           Left Ovary           Left Fallopian Tube      Male -           NONE

5. Abdominal Wall & Cavity The abdomen is the part of the trunk inferior to the thorax. Its musculomembranous walls surround a large cavity (the abdominal cavity) is bounded superiorly by the diaphragm and inferiorly by the pelvic inlet . The abdominal cavity may extend superiorly as high as the fourth intercostal space, and is continuous inferiorly with the pelvic cavity. It contains the peritoneal cavity and the abdominal viscera.

6. LAYERS OF THE ABDOMINAL WALL  (external to internal): Skin Superficial fascia (or subcutaneous tissue) Muscles and associated fascia Parietal peritoneum The Superficial Fascia Above the umbilicus : A single sheet of connective tissue. This continuous with the superficial fascia in other regions of the body. Below the umbilicus : It is divided into two layers; the fatty superficial layer (Camper’s fascia) and the membranous deep layer ( Scarpa’s fascia). Superficial vessels and nerves run between these two layers of fascia. Muscles of the Abdominal Wall There are five muscles in the abdominal wall. They can be divided into two groups: Vertical muscles  – There are two vertical muscles, situated near the mid-line of the body. the  Rectus Abdominis and  Pyramidalis . Flat muscles  – There are three flat muscles, situated laterally . the  external oblique ,  internal oblique  and  transversus abdominis .

7. ABDOMINAL VISCERA AND PERITONEAL CAVITY Visceral peritoneum is a thin membrane (the peritoneum) lines the walls of the abdominal cavity and covers much of the viscera. The parietal peritoneum lines the walls of the cavity and the visceral peritoneum covers the viscera. Between the parietal and visceral layers of peritoneum is a potential space ( the peritoneal cavity ). Abdominal viscera either are suspended in the peritoneal cavity by folds of peritoneum ( mesenteries ) or are outside the peritoneal cavity. Organs suspended in the cavity are referred to as intraperitoneal ; organs outside the peritoneal cavity, with only one surface or part of one surface covered by peritoneum, are retroperitoneal . The peritoneal cavity is subdivided into the greater sac and the omental bursa (lesser sac) : The greater sac accounts for most of the space in the peritoneal cavity, beginning superiorly at the diaphragm and continuing inferiorly into the pelvic cavity. The omental bursa is a smaller subdivision of the peritoneal cavity posterior to the stomach and liver and is continuous with the greater sac through an opening, the omental ( epiploic ) foramen .

8. Esophagus The esophagus is a tubular structure that joins the pharynx to the stomach. The esophagus pierces the diaphragm slightly to the left of the midline and after a short course of about 0.5 inch. (1.25 cm) enters the stomach on its right side. It is deeply placed, lying behind the left lobe of the liver It is a straight muscular tube connecting the oral cavity to the stomach It is about 25cm long and 2cm wide

9. The esophagus is a muscular canal, about 23 to 25 cm. long, extending from the pharynx to the stomach. It begins in the neck at the lower border of the cricoid cartilage, opposite the sixth cervical vertebra, descends along the front of the vertebral column, through the superior and posterior mediastinum, passes through the diaphragm, and, entering the abdomen, ends at the cardiac orifice of the stomach, opposite the eleventh thoracic vertebra.

10. Esophageal constrictions Normally, the esophagus has three anatomic constrictions at the following levels . 1-At the esophageal inlet, where the pharynx joins the esophagus, behind the cricoid cartilage (14-16 cm from the incisor teeth). 2-Where its anterior surface is crossed by the aortic arch and the left bronchus (25-27 cm from the incisor teeth). 3-Where it pierces the diaphragm (36-38 cm from the incisor teeth). The distances from the incisor teeth are important as is useful for diagnostic endoscopic procedures.

11. Gastro esophageal junction The junction between the esophagus and the stomach (the gastro esophageal junction or GE junction) is not actually considered a valve, although it is sometimes called the cardiac sphincter, cardia or cardias , it actually better resembles a structure. In much of the gastrointestinal tract , smooth muscles contract in sequence to produce a peristaltic wave which forces a ball of food (called a bolus ) while in the esophagus. In humans, peristalsis is found in the contraction of smooth muscles to propel contents through the digestive tract.

12. Stomach The stomach is a dilated part of the alimentary canal between the esophagus and the small intestine. It occupies the left upper quadrant, epigastric, and umbilical regions, and much of it lies under cover of the ribs. Its long axis passes downward and forward to the right and then backward and slightly upward.

13. The stomach lies between the oesophagus and the duodenum (the first part of the small intestine ). It is on the left upper part of the abdominal cavity . The top of the stomach lies against the diaphragm . Lying behind the stomach is the pancreas . The greater omentum hangs down from the greater curvature . Two sphincters keep the contents of the stomach contained. They are the esophageal sphincter (found in the cardiac region, not an anatomical sphincter) dividing the tract above, and the Pyloric sphincter dividing the stomach from the small intestine.

14. The stomach is surrounded by parasympathetic (stimulant) and orthosympathetic (inhibitor) plexuses (networks of blood vessels and nerves in the anterior gastric, posterior , superior and inferior , celiac and myenteric), which regulate both the secretions activity and the motor (motion) activity of its muscles. In adult humans, the stomach has a relaxed, near empty volume of about 45 ml. Because it is a distensible organ, it normally expands to hold about 1 litre of food , but can hold as much as 2-3 liters. The stomach of a newborn human baby will only be able to retain about 30ml.

15. Sections of Stomach The stomach is divided into 4 sections, each of which has different cells and functions. The sections are: Cardia Where the contents of the esophagus empty into the stomach. Fundus Formed by the upper curvature of the organ. Body or Corpus The main, central region. Pylorus The lower section of the organ that facilitates emptying the contents into the small intestine.

16. Anatomy of Small Intestine

17. Small intestine The small intestine is the longest part of the gastrointestinal tract and extends from the pyloric orifice of the stomach to the ileocecal fold. This hollow tube, which is approximately 6-7 m long with a narrowing diameter from beginning to end, consists of the duodenum, the jejunum, and the ileum.

18. Duodenum The first part of the small intestine is the duodenum. This C-shaped structure, adjacent to the head of the pancreas, is 20-25 cm long and is above the level of the umbilicus; its lumen is the widest of the small intestine . It is retroperitoneal except for its beginning, which is connected to the liver by the hepatoduodenal ligament, a part of the lesser omentum.

19. Conti………… The duodenum is divided into four sections 1.superior part 2.descending part 3. inferior part 4. ascending part

20. The superior part (first part) extends from the pyloric orifice of the stomach to the neck of the gallbladder The descending part (second part ) of the duodenum is just to the right of midline and extends from the neck of the gallbladder to the lower border of vertebra LII. This part of the duodenum contains the major duodenal papilla, which is the common entrance for the bile and pancreatic ducts,and the minor duodenal papilla,

21. The inferior part (third part) of the duodenum is the longest section, crossing the inferior vena cava the aorta, and the vertebral column . The ascending part (fourth part) of the duodenum passes upward on, or to the left of, the aorta to approximately the upper border of vertebra LII and terminates at the duodenojejunalflexure .

22. Jejunum The jejunum represents the proximal two-fifths. It is mostly in the left upper quadrant of the abdomen and is larger in diameter and has a thicker wall than the ileum. Additionally, the inner mucosal lining of the jejunum is characterized by numerous prominent folds that circle the lumen

23. Ileum Ileum makes up the distal three-fifths of the small intestine and is mostly in the right lower quadrant. The ileum opens into the large intestine where the cecum and ascending colon join together.

24. Large intestine The large intestine extends from the distal end of the ileum to the anus, a distance of approximately 1.5 m in adults. It absorbs fluids and salts from the gut contents, thus forming feces, and consists of the cecum , appendix, colon, rectum.

25. Cecum and appendix The cecum is the first part of the large intestine It is inferior to the ileocecal opening and in the right iliac fossaThe cecum is continuous with the ascending colon at the entrance of the ileum and is usually in contact with the anterior abdominal wall. The appendix is a narrow, hollow, blind-ended tube connected to the cecum . It has large aggregations of lymphoid tissue in its walls and is suspended from the terminal ileum by the mesoappendix , which contains the appendicular vessels.

26. colon The colon extends superiorly from the cecum and consists of the ascending, transverse,descending , and sigmoid colon . Its ascending and descending segments are retroperitoneal and its transverse and sigmoid segments are intraperitoneal . The final segment of the colon (the sigmoid colon) begins above the pelvic inlet and extends to the level of vertebra SIII, where it is continuous with the rectum . This S-shaped structure is quite mobile except at its beginning, where it continues from the descending colon.

27. Rectum and anal Extending from the sigmoid colon is the rectum . The rectosigmoid junction is usually described as being at the level of vertebra SIII or at the end of the sigmoid mesocolon because the rectum is a retroperitoneal structure. The anal canal is the continuation of the large intestine inferior to the rectum.

28. Anatomy of Liver The liver is a reddish brown organ with four lobes of unequal size and shape. A human liver normally weighs 1.4–1.6 kg (3.1–3.5 lb), and is a soft, pinkish-brown, triangular organ. It is both the largest internal organ (the skin being the largest organ overall) and the largest gland in the human body. It is located in the right upper quadrant of the abdominal cavity , resting just below the diaphragm . The liver lies to the right of the stomach and overlies the gallbladder

29. The biliary tree&Biliary Flow The term biliary tree is derived from the arboreal branches of the bile ducts. The bile produced in the liver is collected in bile canaliculi , which merge to form bile ducts . Within the liver, these ducts are called intrahepatic (within the liver) bile ducts, and once they exit the liver they are considered extrahepatic (outside the liver). The intrahepatic ducts eventually drain into the right and left hepatic ducts , which merge to form the common hepatic duct . The cystic duct from the gallbladder joins with the common hepatic duct to form the common bile duct . Bile can either drain directly into the duodenum via the common bile duct, or be temporarily stored in the gallbladder via the cystic duct. The common bile duct and the pancreatic duct enter the second part of the duodenum together at the ampulla of Vater .

30. Lobes of The Liver

31. the liver is Divided into four lobes based on surface features. The falciform ligament is visible on the front ( anterior side) of the liver. This divides the liver into a left anatomical lobe , and a right anatomical lobe . If the liver is flipped over, to look at it from behind (the visceral surface), there are two additional lobes between the right and left. These are the caudate lobe (the more superior) and the quadrate lobe (the more inferior). From behind, the lobes are divided up by the ligamentum venosum and ligamentum teres (anything left of these is the left lobe), the transverse fissure (or porta hepatis ) divides the caudate from the quadrate lobe , and the right sagittal fossa , which the inferior vena cava runs over, separates these two lobes from the right lobe. Each of the lobes is made up of lobules; a vein goes from the centre, which then joins to the hepatic vein to carry blood out from the liver. On the surface of the lobules, there are ducts, veins and arteries that carry fluids to and from them.

32. Anatomy of Gall Bladder

33. Conti…………… he gallbladder is a hollow system that sits just beneath the liver.In adults, the gallbladder measures approximately 8 cm in length and 4 cm in diameter when fully distended. It is divided into three sections: fundus , body and neck. The neck tapers and connects to the biliary tree via the cystic duct , which then joins the common hepatic duct to become the common bile duct . The angle of the gallbladder is located between the costal margin and the lateral margin of the rectus abdominis muscle .

34. Parts of Gall Bladder The gall bladder is consisting of the following parts if seen from below upwards and also backwards: the fundus , body, and the neck. Each of them is given a brief description below:

35. Conti…….. Funds: the lower free and the expanded end of the Gall bladder is known as the fundus of the gall bladder. It is projection from below the liver and its direction is downwards, forwards, and also to the right where it comes in contact with the anterior wall of the abdomen where it makes an angle of about thirty degrees.

36. Conti………….. Body: the body of the gall bladder is the portion that is lying between that of the funds and also the neck. The direction of the body is upwards, backwards, and to the left.

37. Conti……………….. Neck: it is the “S” shaped curve present above the body, and extends up to the cystic duct. Direction is upwards, forwards and then takes a turn and becomes downwards and backwards. Sometimes there is a presence of some diverticulum’s known as the Hartmann’s pouch and this portion is often termed as the isthmus of the gall bladder.

38. Anatomy of Spleen spleen, in healthy adult humans, is approximately 11 centimeters (4.3 in) in length. It usually weighs between 150 grams (5.3 oz) and 200 grams (7.1 oz) and lies beneath the 9th to the 12th thoracic ribs.

39. Anatomy Of Kidney

40. Relationship of the Kidneys to Vertebra and Ribs 57 Figure 23.1b They are retroperitoneal and are located in the abdominal cavity. They are at the level of T12 to L3, so they are at the costal margin, and the ribs protect them a little. Even though they are protected by thoracic ribs, they are NOT in the thoracic cavity because they are below the diaphragm.

41. Conti…………… The kidney has a bean-shaped structure, each kidney has concave and convex surfaces. The concave surface, the renal hilum , is the point at which the renal artery enters the organ, and the renal vein and ureter leave. The kidney is surrounded by tough fibrous tissue, the renal capsule, which is itself surrounded by perinephric fat , renal fascia (of Gerota ) and paranephric fat .

42. 59 Arcuate arteries Interlobular arteries Interlobar arteries Renal fascia

43. Conti………… The superior border of the right kidney is adjacent to the liver; and the spleen, for the left border. Therefore, both move down on inhalation. The kidney is approximately 11–14 cm in length, 6 cm wide and 4 cm thick. It weighs about 150 Grams. The Superior part of the kidney has a suprarenal gland(Adrenal Gland)

44. Blood Supply to Kidney 61 AORTA  RENAL ARTERY  SEGMENTAL ARTERIES  INTERLOBAR ARTERIES  ARCUATE ARTERIES (form arcs)  INTERLOBULAR ARTERIES INTERLOBULAR VEIN  ARCUATE VEIN  INTERLOBAR VEINS  SEGMENTAL VEINS  RENAL VEIN  INF. VENA CAVA

45. Internal Anatomy of the Kidneys 62 Figure 23.3b Interlobar artery

46. Ureter the ureters are muscular tubes that propel urine from the kidneys to the urinary bladder . In the adult, the ureters are usually 25–30 cm (10–12 in) long and ~3-4 mm in diameter. In humans, the ureters arise from the renal pelvis on the medial aspect of each kidney before descending towards the bladder on the front of the psoas major muscle. The ureters cross the pelvic brim near the bifurcation of the iliac arteries (which they run over). This is a common site for the impaction of kidney stones (the others