Describe Abdominal Viscera Flashcards
Describe the peritoneum
Thin serous membrane consisting of two layers, the paritetal and visceral peritoneum
Parietal peritoneum is served by the same blood and lymphatic vasculature and the same somatic nerve supply as is the region of the wall it lines.
Pain from the parietal peritoneum is generally well localized except on the inferior surface of the central part of the diaphragm where innervation is provided by the phrenic nerve, irritation here is referred to the c3-5 dermatomes
- The visceral peritoneum and the organs it covers are served by the same blood and lymphatic vasculature and visceral nervey supply. Insensitive to touch, heat, cold and laceration. Is stimulated by stretch and chemical irritation. Poorly localized, foregut derivative transfer to the epigastrium, midgut to eh umbilical and hindgut to the pubic region.
- Peritoneal cavitiy is a potential space filled with serous fluid, nil organs. Completely closed in males but open in females thorugh the uterine tubes, uterine cavity and vagina and this constitutes a potential pathway of infection
Describe intraperitoneal organs:
Almost completely covered with visceral peritoneum. Not truly within the cavity.
Stomach, spleen, transverse colon, small intestine
Describe retroperitoneal organs
Lie behind the peritoneum or only one surface covered in peritoneum
-pancreaus, duodenum, ureters, aortoa
Discuss omentum
- Areas of doubling of the visceral peritoneum between the stomach and other organs
- Greater omentum is a prominent peritoneal fold that hands down from the greater curvature of the stomach and the proximal part of the duodenum. After descending it folds back and attaches to the anterior surface of the transverse colon and its mesentery
- Less omentum connects the lesser curvature of the stomach and the proximal part of the duodenum to the liver, it also connects the stomach to the triad of sturctures that run between the durodenum and liver
Discuss mestentary:
Areas of doubling of the visceral peritoneum which connects intra-abdominal organs to the posterior wall
It provides a means for the neurovascular commination between the organ and the body wall.
Describe peritoneal ligaments and attachments of the liver and stomach
Consists of a double layer of peritoneum that connect an organ with another organ or the abdominal wall.
The liver is connected to
1: the anterior abdominal wall by the falciform ligament
2: the stomach by the hepatogastric ligament the membranous portion of the lesser omentum
3: duodenum by the hepatoduodenal ligament the thickened free edge of the lesser omentum which conducts the portal triad. The hepatogastric and hepatoduodenal ligaments are continuous parts of the lesser omentum
The stomach is connected to
1: inferior surface of the diaphragm by the gastrophrenic ligament
2: spleent by the gastrosplenic ligament which reflects to the hilum of the spleen
3: transverse colon by the gastrocolic ligament the apronlike part of the greater omentum which descends from the greater curvature
Discuss the subdivisions of the peritoneal cavity:
After the rotation and development of the greater curvature of the stomach during development the peritoneal cavity is divided into the greater and lesser peritoneal sacs.
The omental bursa lies posterior to the stomach can lesser omentum
The transverse mesocolon divides the abdomen into a supracolic compartment and an infracolic compartment. Free communications occurs between the supracolic and infracolic compartment via the paracolic gutters the grooves between the ascending or descending colon and the posterolateral abdominal wall
Discuss the omental bursae
Extensive saclike cavity that lies posterior to the stomach, less omentum and adjacent structures
The omental bursae has a superior recess limited superiorly by the diaphragm and the posterior layers of the coronary ligmanet of the liver
The inferior recess between the superior parts of the layers of the greater omentum. The omental busa permits free movment of the stomach
The omental busa communicates with the greater peritoneal sac through the omental foramen an opeing situated posterior to the free edge of the lesser omentum.
Discuss the omental foramen
Boundaries
Anterior: the hepatoduodenal ligament containing the portal vein, heaptic artery and bile duct
Posterior: the IVC and right crus of the diaphragm covered anteriorly with parietal peritoneum
Superiorly: the liver covered with visceral peritoneum
Inferiorly the superior or first part of the duodenum.
Discuss the eospophagus
A muscular tube (approximately 25cm in length) with an average diameter of 2cm that conveys food from the pharynx to the stomach. There are three constriction of the oesophagus
1: cervical constriction: at its beginning at the pharenygoesophageal junction, approximately 15 cm from the incisor teeth, caused by the cricopharyngeus muscle
2: thoracic constriction: occurs where it is first crossed by the arch of the aorta
3: diaphragmatic constriction where it passes through the oesophageal hiatus of the diaphragm.
The oesophagus
Follows the curve of the vertebral column
Has internal circular and external longitudinal layers of muscles. In its superior third the external layer consists of voluntary striated muscles
Passes through the elliptical oesophageal hiatus at the level of T10
Terminates by entering the cardiac orifice at the level of the 7th left costal cartilage and t11 vertebra
Is encircled by the oesophageal nerve plexus distally
Attached to the phrenicoesophageal ligament an extension of inferior diaphragmatic fascia
Disucss the esophagogastric junction
Lies to the left of T11 vertebra on the horizonatla plane that passes through the tip of the xiphoid process. The Z line is a jagged line where the mcuosa abruptly changes from oesophageal to gastric
The diaphragmatic musculature froms an oeophageal physiological sphincter that contracts and relaxes
Discuss the arterial supply to the abdominal oesophagus
Left gastric artery a branch of the caeliac trunk
Left inferior phrenic artery
The venous drainage is through both the left gastric vein into the portal system and into the systemic circulation via the oesophageal vein draining into the azygos
Lymphatic drain into the left gastric lymph nodes efferent from this nodes drain mainly to the celiac lymph nodes
Discuss innervation of the abdominal oesophagus
Oesophageal nerve plexus formed by the vagal trunks
Thoracic sympathetic trunks via the greater splanchnic nerves
Discuss the stomach
Can expand to hold 2-3 litres
The stomach has four parts
- cardia: the part surrounding the cardial orifice
- Fundus: the dilated superior part that is related to the left dome of the diaphragm and is limited inferior by the horizontal plane of the cardial orifice. The superior part of the fundus can reach the level of the left 5th intercostal space . Cardiac notch is between the fundus and the oesophagus
- Body:
- Pyloric part: the funnel shaped outflow. The pyloric antrum leads into the pyloric canal its narrowest part. The pylorus the distal sphincteric region of the pyloric part is a marked thickening of the circular layer of smooth muscle
Discuss the curvatures of the stomach
- Lesser curvature: forms the shorter concave border of the stomoach. The angular incisure is the sharp indentation that indicates the junction of the body and the pyloric part of the stomach
- Greater curvature: forms the longer convex border of the stomach
Discuss the interior of the stomach
Covered in a continuous mucous layer that protects its surface from the gastric acid the stomach’s glands secrete. When contracted the gastric mucosa is through into longitudinal reidges called the gastric folds or gastric rugae
Discuss relations of the stomach
Anterior
- diaphragm
- left lobe of the liver
- anterior abdominal wall
Posterior
- omental bursa – forms most of the anterior wall of the omental bursa
- pancreas
Stomach bed (which the stomach lies in supine position) from superior to inferior
- left dome of the diaphragm
- spleen
- left kidney
- suprarenal gland
- splenic artery
- pancreas
- transverse mesocolon and colon
Describe the foregut
- oesophagus
- stomach
- proximal half of duodenum
- liver
- gall bladder
- pancreus
- spleen
Describe the midgut
Duodenum distal half
- jejunum
- iliem
- caecum
- appendix
- ascending colon
- hepatic flexure
- transverse colon (proximal two-third)
Describe the hindgut
- Distal third of the transverse colon
- descending colon
- rectum
Describe the abdominal aorta
Begins at the aortic hiatus of the diaphragm at the level of t12
Ends at the birfucation of the common iliac arteries at the level L4
Anterior artery
Coeliac trunk – foregut. Lies at the level of the transpyloric plane (L1)
Superior mesenteric – mid gut (lower border of L1)
Inferior mesenteric – hind gut (inferior L3)
Discuss the branches of the coeliac trunk
- Left gastric
- splenic
- common hepatic
- inferior phrenic arteries can branch from the coeliac trunk (supply the diaphragm)
Discuss the left gastric
Ascends from the ceoliac trunk retroperitonealy to eosophageal hiatus, giving rise to an oesophageal branch the n descending along the lesser curvature to anastomose with the right gastric artery.
Supplies the disal oesophagus and lesser curvature of the stomach
Discuss the splenic artery
Runs retroperitoneally along the superior border of the pancreas, traverses spenorenal ligament to hilum of the spleen
Supplies the pancreaus, spleen and greater curvature and posterior stomach
Branches
- posterior gastric: supplies the posterior wall and fundus of the stomach
- left gastromental: left portion of greater curvature of stomach
- short gastric: fundus of the stomach
Discuss the hepatic artery
Pass retroperitoneally to reach hepatoduodenal ligament; passing between layers of the pora hepatis; birfucates into right and left hepatic arteries
Supplies the liver, gallbladder, biliary ducts, stomach, duodenum, pancreuas and respective lobes of liver
Branches
- Right gastric: runs along the lesser curvature of the stomach to anastomose with the left gastric
- right and left hepatic arteries
- gastroduodenal
Describe the gastroduodenal artery
Descends retroperitoneally, posterior to gastroduodenal junction
Suppleis stomach pancreas and first part of duodenum
Branches:
- Right gastro-omental: right portion of greater curvature of the stomach
- superior pancreaticodudenal: proximal portion of duodenum and superior part of head of pancreas
Describe the venous drainage of the stomach
Parrallel the arteries in position and course
The right and left gastric drain into the portal vein
Short gastric and left gastroomental veins drain into the splenic vein which joins the SMV to form the portal vein
The right gastro-omental drain into the SMV
Discuss the lymphatic drainage of the stomach
Lymphatic accompany the arteries along the lesser and greater curves where the gastric and gastro-omental lymph nodes are located
Lymph from the superior two thirds of the stomach drains along the right and left gastric vessels to the gastric lymph nodes;
Lymph from the right 2/3rd of the inferior third drain along the right gastro-omental vessels to the pyloric lymph nodes
Lymph from the left on third of the greater curvature drains along the short gastric and splenic vessels to the pancreaticoduodenal lymph nodes
Describe the para-sympathetic nerve supply of the stomach
Anterior and posterior vagal trunks and their branches which enter the abdomen through the oesophageal hiatus
The anterior vagal trunk derived mainly from the left vagal nerve usually enters the abdomen as a single branch that lies on the anterior surface of the oesophagus. It runs toward the lesser curvature of the stomach where it give off hepatic and duodenal branches.
The larger posterior vagal trunk is derived from the right vagal nerve. Supplies the anterior and posterior surfaces of the stomach. Gives off a ceoliac branch which runs to the celiac plexus and then continues along the lesser curvature given rise to posterior gastric branches
The sympathetic is through th t6-t9 through the greater splanchnic nerve
Describe the duodenum
First and shortest part of the small intestine (25cm) is also the widest and most fixed.
C-shaped course around the pancreas
Begins at the pyloris and ends in the duodenojejunal junction at the level of L2. This junction normally forms an acute angle the duodenojejunal flexure . Fixed by peritoneum to structures on the posterior abdominal wall and is considered to be partially retroperitoneal. Divisible into four parts
1: superior part: short (approximately 5cm) and lies anterolateral to the body of the L1 Vertebra
2: descebing part longer (7-10) and descends along the L1-l3 vertebrae
3: Horizontal (6-8) cross the l3
4: ascending part (5c) and beings at the left of the l3 and raises superiorly as far as the superior border of the l2 vertebra
The first 2cm of the superior part of the duodenum immediately distal to the pyloris has a mesentery and is mobile. This free part is called the ampulla. The rest have no mesentery and a immobile as they are retroperitoneal
Describe the superior part of the duodenum
Overlapped by the liver and gallbladder.
Has the hepatoduodenal ligament
Relations:
- Anterior: peritoneum, gallbladder, quadrate lobe of the liver
- Posterior: bile duct, gastroduodenal artery, portal vein, IVC
- Superior: neck of gallbladder
- Inferior: neck of pancreuas:
Describe the descending part of the duodenum
Recieves the hepatopancreatic ampulla which opens on an eminences called the major duodenal papilla
Relations
Anterior: transverse colon, transverse mesocolon, colis of small intestine
Posterior: hilum of right kidney, renal vessels, ureter, psoas major
Medial: head of pancreas, pancreatic duct bile duct
Describe the relations of the 3rd part of the duodenum
Anterior: SMA, SMV, coils of small intestine
Posterior: right psoas major, IVC, Aorta, right ureter
Superior: head and uncinated process of pancrease. Superior mesenteric vessels
Describe the relations of the ascending part of the duordenum
Anterior: beginning of root of mesentery, Colis of jejunum
Posterior: left psoas major, left margin of aorta
Medial: head of pancreas
Superior: body of pancreas
Describe the blood supply to the duodenum
Superior pancreaticoduodenal arteries gastroduodenal artery of the common hepatic
Inferior pancreaticoduodenal artery of the SMA supplies duodenum distal to the entry of the bile duct
Veins follow the arteries and drain into the portal system.
Discuss the ilieum and jejunum
The second part of the small intestine the jejunum at the duodenojejunal flexure where the alimentary tract resumes an intraperitoneal course. The ilieum the third portion ends at the ileocaeacl junction.
Together the ilieum and jejunum are 6-7 m long , jejunum(2/5) and ilieum 3/5th the length.
Jejunum lies in the left upper quadrant
Ilieum lies in the right lower quadrant Specialiased lymphatic vessels in the intestinal villi that absorb fat called lacteals. They empty their milk like fluid into the lymphatic plexuses in the walls of the jejunum and lieum. Within the mesentery the lymph nodes pass sequentially through three groups of lymph nodes
1) Juxtu-intestinal lymph nodes
2) Mesenteric lymph nodes
3) Superior central nodes
These drain into the ileocolic lymph nodes
Discuss the large intestine
Site where water is absorbed from the indigestible residues of the liquid chyme converting it into semisolid stool
Can be differentiated from the small intestine by
1: omental appendices, small, fatty omentum like projections
2: three teni coli (thicekend bands of smooth muscle representing most of the longitudinal coat)
- mesocoli: to which the transverse and simoid mesocolons attach
- omental to which the omental appendices attach
- free tow which neither mesocolons nor omental appendices attach
The tenia coli begin at the appendix as as the thick longitudinal layer of the appendix and then split into three merging again at the rectosigmoid junction
Describe the Caecum
First part of the large intestine
It is a blind intestinal pouch approximately 7.5cm in both length and breath
Lies with 2.5cm of the inguinal ligament
Nil mesentery but freely moveable
Terminal ilieum enters the caecum obliquely and partly invaginates into it. This manner of entrance produce ileocolic lips at the ileal orifice which form the ileal papilla. These meet laterally to form the frenula which when the caecum contracts tight to prevent reflux
Describe the appendix
Blind intestinal diverticulum (6-10cm) that contains masses of lymphoid tisseus. It arises from the posteriormedial aspect of the caecum inferior to the ileocaecal junction.
Appendix has a short triangular mesentery
Discuss the nerve supply to the caecum and appendix
Derives parasympathetic and sympathetic from the superior mesenteric plexus . Sympathetic nerves originating in the lower thoracic part of the spinal cord and the parasympathetic nerves fibers derive from the gagus nerve
Describe the SMA
Branches unite to form loops or arches called arterial arcades which give rise to straight arteries called vasa recta
Arises anteriorly form the lower border of the L1 vertebrae
Runs in root of mesentery to ileocaecal junction
Branches
- Inferior pancretoduodenal
- intestinal (jejunal and ileal)
- middle colic which supplies the transverse colon
- right colic: which supplies the ascending colon
- ileocolic: terminal branch of SMA supplies the ilieum, caecum and ascending colon. Appendicular is a branch of the ileocolic and supplies the appendix
The marginal artery anastomoses the SMA with the IMA is weakest at the left colic flexure
Describe the IMA
Arises at the level of L3
Descends retroperitoneally to left of abdominal aorta
Branches
- left colic which supplies the descending colln
- sigmoid which supplies the descending and sigmoid colon
- superior rectal: proximal part of rectum
- middle rectal: midpart of rectum
- inferior rectal: distal part of the rectum and anal canal
Describe the ascending colon:
Pass superiorly on the right side of the abdominal cavity from the caecum to the liver where it turns left at the right colic flexure
Narrower then the caecum and is secondarily retroperitoneal
Lymphatic pass first the epicolic and paracolic lymph nodes next to the ileocolic and intermediate right colic lympn nodes to the superior mesenteric lymph nodes
Nervous supply from the superior mesenteric plexus
Describe the transverse colon (45cm) long
Most mobile part of the intestine
Runs from the left to right colic flexure
Lies anterior to the inferior part of the left kidney and attaches to the diaphragm through the phreniocolic ligament.
The transverse mesocolon loops down often inferior to the level of the iliac crest and is adherent ot or fused with the posterior wall of the omental busa.
The root of the transverse mesocolon lies along the inferior border of the pancreas and is continuous with the parietal peritoneum
Lymphatic drainage is to the middle colic and eventually into the superior mesenteric
Describe the descending colon
Secondarily retroperitoneal position
Short mesentery in 33% of people
Describe the sigmoid colon
S shaped loop of variable length (usually approx. 40cm) links the descending colon and the rectum
Extends from the iliac fossa to the levee of S3
The teniae coli terminate approximately 15 cm from the anus
Long mesentery
The left ureter and the division of the left common iliac artery lie retroperitoneally posterior to the apex of the root of the sigmoid mesoclon
Lymph drains through the intermediate colic lymph nodes along the left colic artery and then into the inferior mesenteric lymph nodes
Discuss the spleen
12cm long 7cm wide, convex
Receives the protection of the lower thoracic cage
Largest of the lymphatic organs
Completely surrounded by peritoneum except at the splenic hilum where the splenic branches of the splenic artery and vein enter and leave
Located at the level of the 9th-11th ribs and separated from the diaphragm by the costodiaphragmatic recess
Relations:
Anterior: stomach
Posterior: the left part of the diaphragm which separates it from the pleura, lung and ribs 9-11
Inferior: the left colic flexure
Medially: kidney
Splenic capsule is fibrous and composed of dense fibroeleastic connective tissue . Internally the trabeculae arising from the deep aspect of the capsule carries blood vessels to and from the parenchyma or splenic pulp
Spleen contacts the posterior wall of the stomach and is connected to its greater curvature by the gastrosplenic ligament and to the left kidney by the splenorenal ligament. These ligaments containing splenic vessels are attached to the hilum of the spleen. The hilum of the spleen is in contact with the tail pancreas
Describe the blood supply to the spleen
The splenic artery is the largest branch of the celiac trunk and follows a tortuous course posterior to the omental bursa, anterior to the left kidney and superior to the border of the pancreaus. At the hilum of the spleen it divides into five or more branches. Lack of anastomoses results in the formation of vascular segments 2 in 84% of spleens and 3 in the other
Venous drainage is by the splenic veins which is supplied by many tributaries. It is joined by the IMV and runs posterior to the body and tail of the pancreas. It then joins the SMV posterior to the neck of the pancreas to form the portal vein
Lymph drainage is to the pancreaticosplenic lymph nodes
Discuss the pancreas
Retroperitoneal posterior to the stomach between the duodenum on the right and the spleen on the left
Four parts Head: Expanded part of the gland that is embraced by the c-shaped duodenum. Firmly attached to the descending and horizontal portion of the duodenum. The uncinated process is a projection from the inferior part of the pancreatic head. Rest posteriorly on the IVC, right renal artery and vein and the left renal vein
Neck: (1.5-2cm): Adjacent to the pyloris of the stomach. SMV joins the splenc posterior to this portion
Body: Passes over the aorta and lies at the L2 vertebrae. Posterior portion is in contact with the aorta, SMA, left suprarenal gland and left kidney and renal vessels.
Tail: Anterior to the kidney
The main pancreatic duct begins in the tail of the pancreaus and runs through the parenchyma to the head of the pancreas. Most of the time the main pancreatic duct and the bile duct unite to form the hepatopancreatic ampulla (of Vater). In 25% of people the ducts open separately. There is a smooth muscle sphincter around the main pancreatic duct, the bile duct and the ampulla of vater(the sphincter of oddi)
The accessory pancreatic duct opens at the summit of the minor duodenal papilla, is normally communicating with the main duct
Describe the blood supply to the pancreas
Most of the blood supply to the pancreas comes from the tortous splenic artery which forms several aracades with pancreatic branches of the gastrodurodenal and SMA
The anterior and posterior superior pancreatoduodenal branch of the gastroduodenal and the anterior and posterior inferior pancreatoduodenal of the SMA supply the head
Most of the venous drainage is into the portal system
Most lymphatic end in the pancreaticosplenic lymph nodes which in turn drain into to the superior mesenteric lymph nodes or to the celiac lymph nodes via the hepatic lymph nodes
Discuss the liver
Largest gland in the body
Weighs approximately 1.5kg
Two surfaces a convex diaphragmatic surface and a relatively flat or even concave visceral surface
Subphrenic recesses – superior extensions of the peritoneal cavity exist between the diaphragm and the anterior and superior aspects of the liver. These are separated into right and left by the falciform ligament which joins the liver to the anterior abdominal wall (rectus sheath) as low as the umbilicus
The round ligament is contained within the inferior portion of the falciform and moves between the quadrate and left lobe of the liver
The hepatorenal recess (morison pouch) is the postero superior extension of the subhepatic space lying between the right part of the visceral surface and the right kindeyh. Gravity dependent when supine and receives drainage from the omental bursae
The posterior part of the liver is covered in peritoneum except for its bare portion in which the liver is in contact with the diaphragm. The bare area is demaracated by reflection of the peritoneum from the
diaphragm to it as the anterior (upper) and posterior(lower) layers of the coronary ligament. The coronary ligament holds the liver onto the inferior portion of the diaphragm.
The layers of the coronary ligament meet on the right to form the right triangular ligament. The anterior portion of the coronary ligament is continuous on the left with the right layer of the falciform and the posterior layer is continuous with lesser omentum.
The left coronary ligament also join to form the left triangular ligament. The IVC traverses a deep groove in the bare area
The visceral surface of the liver is covered with peritoneum except at the fossa for the gallbladder and the porta hepatis
Right sagittal fissures is the continuous groove formed anteriorly by the fossa for the gallbladder and posteriorly by the groove for the venacava. The left sagittal fissues is the continuous groove formed anteriorly by the fissue for the ligamentum teres (round ligament) and posteriorly by the fissure for the ligamentum venosum.
The lesser omentum enclosing the portal triad passes from the liver to the lesser curvature of the stomach and the first 2 cm of the superior part of the duodenum. The thick free edge of the lesser omentum extends between the porta hepatis and the duodenum(the hepatoduodenal ligament). The sheet like remainder (the hepatogastric ligament)
Discuss the anatomical lobes of the liver
Two topographical lobes and two accessory lobes
These are not true lobes as the term is generally used in relation to glands and are only secondarily related to the livers internal architecture
The essentially midline plane formed by the falciform ligament and the left sagittal fissure froms the right and much smaller left lobe
The right and left sagittal fissures and the transverse porta hepatis demarcates two accessory lobes the anterior and inferior quadrate and the posterior superior caudate
Discuss functional subdivisions of the liver
The liver functionally has independent left and right lobes which are much more equal in size then the anatomical lobes. Each receives its own primary branch of the hepatic artery and portal vein and is drained by its own hepatic duct
The caudate lobe can be considered a third liver, its vascularization is independent of the bifurcation of the portal triad and is drained by one or two small heaptic veins which enter directly into the IVC distal to the main hepatic veins . Can be further subdivided into 8 surgical resectable segment each served by independent blood supply
Discuss vascular supply of the liver.
Dual blood supply
Portal vein brings 75-80% of blood. This contains about 40% more oxygen then venous blood returning to the heart from the systemic circulation
Carries all nutrients absorbed from the GIT except for fats
Hepatic artery supplies 20-25%
Portal veins is formed by the splenic and SMT behind the neck of the pancreas. It ascends anterior to the IVC as part of the portal triad in the hepatoduodenal ligament
The hepatic arteries are a branch of the caeliac trunk – the common gives rise to the gastrodudenal and the right and left hepatic arteries
At the porta hepatis the portal and common hepatic bifurcate into the right and left branches supplying the right and left livers respectively. They continue to bificate to form 8 vascularly independent segments
The left right and intermediate hepatic veins formed by the union of collecting veins that in turn drain the central veins open into the IVC just inferior to the diaphragm.
Discuss lymphatic drainage of the liver
Liver is the major lymph producing organ. Between ¼ and 50% of the lymph received by the thoracic duct is from the liver
Superficial lymphatic vessels occur in the subperitoneal fibrous capsule of the liver and the deep in the connective tissue which accompany the ramifications of the portal triad
Most lymph is formed in the perisinusoidal space (of Disse)and drains to the deep lymphatics in the surrounding intralobular portal triads .
Superificial lymph drains into the hepatic lymph nodes, efferent vessels from these nodes drain into celiac lymph nodes which in turn drain into the chyle cistern, a dilated sac at the inferior end of the thoracic duct.
Superficial lymphatic from the posterior asepctes of the diaphragmatic and visceral surfaces of the liver drain into the bare space into phrenic lymph nodes
Deep drains into the posterior mediastinal lymph nodes
Discuss nerve supply to the liver
Via the hepatic plxus the largest derivative of the celiac plexus
Discuss bilary ducts
Hepatocytes secrete bile into the bile canaliculi formed between them. The canaliculi drain into small interlobular bilary ducts and then into large collecting bile ducts of the intrahepatic portal triads, Which merge to form the right and left hepatic ducts. The right and left hepatic ducts drain the right and left parts of the liver. Shortly after leaving the porta hepatis the right and left hepatic ducts unite to form the common hepatic duct which is joined on the right side by the cystic duct
Discuss the bile duct
Forms in the free edge of the lesser omentum by the union of the cystic duct and the common hepatic duct
The length of the bile duct varies from 5-15cm, depending on where the cystic duct joins the common hepatic duct.
Descends posterior to the superior part of the duodenum and lies in groove on the posterior face of the head of the pancreas
On the left side of the descending portion of the duodenum the bile duct comes into contact with the main pancreatic duct
When the sphincter of oddi is contracted the bile backs up and passes through the cystic duct to the gall bladder.
Discuss the blood supply to the bile duct
- Cystic artery a branch of the right hepatic supplying the proximal part
- right hepatic supplying the middle part
- posterior superior pancreaticoduodenal artery and gastroduodenal artery supply the retroduodenal part of the duct
Discuss the gallbladder
7-10cm long lies in the fossa for the gallbladder on the visceral surface of the liver
The relationship of the gallbladder and the superior part of the duodenum is intermit so much so that at autopsy is often stained with bile. Naturally lies anterior to the duodenum and its neck and cystic duct are immediately superior to the duodenum. Has three parts
- Fundus: the wide end of the organ, projects from the inferior border of the lvier and isually located at the tip of the 9th costal cartilage in the MCL
- Body:
- Neck
Describe the cystic duct
3-4cm long connects neck of the gallbladder with the common hepatic duct. The mucosa of the neck spirals into the spiral fold (spiral valve). This helps keep the cystic duct open and thus bile can easily be diverted into the gall bladder .
Passes between the layers of the lesser omentum usually parallel to the common hepatic duct which ti joins to form the bile duct
Cystic artery from the right hepatic artery supplies the gallbladder and cystic duct
Veins drain to the portal tract
Lymphatic to the hepatic lymph nodes often through the cystic lymph nodes
Supplies by the coeliac nerve plexus, the vagus and the right phrenic
Discuss the portal vein
Formed by the splenic and SMV, anterior to the IVC and posterior to the neck of the pancreas. Large vessel with a short course contained most withint the hepatoduodenal ligament
Collects blood from the SMV, IMV, splenic , gallbladder and pancreas
Splenic with products of RBC breakdown passes mostly to the left liver
Blood from the SMV nutrient dense passes mostly to the right
Discuss the portal systemic anastomoses
Areas in which the portal system communicates with systemic venous system are found in
- the inferior oeophagus
- submucosa of the anal canal
- paraumbilcal region
- posterior aspects of secondarily retroperitoneal viscera or the liver
Nil valves in these anastomoses and blood can flow either way
Describe the kindey
Retroperitoneal
Lie at the level of T12-L3 with the right lying inferior ot the left due to the lvier.
Measure approximately 1052.5
Related superiorly with the diaphragm and inferiorly with the quadratus lumborum
The subcostal nerves and vessels and the iliohypogastric and ilioinguinal nerves descend diagonally across the posterior surface of the kidneys
The liver duodenum and ascending colon are anterior to the right kidney
Left kidney is related to the stomach spleen pacnreaus duodenum and descednign colon.
At the concave medial margin of each kidney is a vertical cleft the renal hilum. The vein is anterior to the artery at the hilum. Renal hilum is the entrance to the renal sinus which is occupied by the renal pelvis, calices, vessels and nerves and a variable amount of fat
The renal pelvis is the flattened funnel shaped expansion of the superior end of the ureter. The renal pelvis receives two or three major calices each of which divides into two or three minor calices. Each minor calyx is indented by the renal papilla the apex of the renal pyramid from which urine is secreted
Describe the ureters*
Muscular ducts 25-30cm in length
Run inferiorly from the apex of the renal hila passing over the pelvic brim at the bifurcation of the common iliac. Run along the lateral wall of the pelvis and enter the urinary bladder. Constricted to a variable degree in three places
1: at the junction of the ureters and renal pelves
2: where the ureters cross the pelvic brim of the pelvic inlet
3: during their passage through the wall of the urinary bladder
The ureters intersect the tips of the transverse processes of the lumbar vetebrae
Arterial supply to the abdominal portion of the ureters is consistently from the renal arteries with less constant branches form the testicular or ovarian arteries, the AA and the common ilaics. These branches approach the ureters medially and divide into ascending and descending branches forming an anastomosis
Veins drain inot the renal or gonadal veins
Lymph drains directly to the right or left lumbar lymph nodes and the common iliac lymph nodes
Discuss the suprarenal glands
Superomedial aspects of the kidney
Surrounded by significant amounts of perinephric fat
Enclosed in renal fascia by which they are attached to the crura of the diaphragm.
Rich blood supply. The suprarenal arteries branch freely before entering the gland and 50-60 arteries penetrate the capsule. Blood supply is from
- superior sprarenal arteries (from the inferior phrenic)
- middle suprarenal arteries (from the abdominal aorta level of the sma)
- Inferior suprarenal arteries (from the renal arteries)
Discuss the vasculature supply of the kidney
Renal artery arises inferior to the celiac trunk at the level of L1-l2
The longer right renal artery passes posterior to the IVC.
Typically, each artery divides close to the hilum into five segmental arteries that are end arteries.
Segments include the superior, anterosuperior, anteroinferior, inferior and posterior segmental arteries
Renal veins exit anterior to the artery and empty into the IVC. The left renal is longer then the right
Lymph drains into the right and left lumbar lymph nods
Discuss the sympathetic innervation of the abdominal viscera
The sympathetic part of the autonomic innervation of the abdominal viscera consists of the
- abdominopelvic splanchnic nerves from the thoracic and abdominal sympathetic trunks
- prevertebral sympathetic ganglia
- abdominal aorta plexus and its extensions, the periarterial plexuses
The abdominopelvic splanchin nerves convey presynaptic fibers to the abdominal viscera and arise from cell bodies in the IML of the gray matter of the spinal cord segements t5-l2,3. They pass through the anterior roots, anteiro rami and white communicating branches of thoracic and upper lumbar spinal nerves to reach the sympathetic trunk. They pass through the paravertebral ganglia or the trunk without synapsing to enter the abominopelvic splanchnic nerves.
The abdominopelvic splanchnic nerves include
- lower thoracic splanchin nerevs (greater, lesser and least)
- Lumbar splanchnic nerves (lumber part of the sympathetic trunks)
Discuss the lower thoracic splanchnic nerves
The main source of presynaptic fibers serving the abdominal viscera
The greater (t5-9/10), lesser (10-11) nad least (12), lower thoracic splanchnic nerves pierce the crus of the diaphragm to supply sympathetic fibers to the celiac, superior mesenteric and aorticorenal sympathetic ganglia respectively
Discuss the lumbar splanchnic nerves
Arise from the abdominal part of the sympathetic trunk. Medially the lumbar sympathetic trunks five off three to four lumber splanchnic nerves which pass to the intermesenteric, inferior mesenteric and superior hypogastric plexuses conveying presynaptic sympathetic fibers to the associated prevertebral ganglia of those plexuses
Discuss postsynaptic sympathetic nerve fibres
The cell bodies of postsynaptic sympathetic neruons consititue the major prevertebral ganglia that cluster around the roots of the major branches of the abdominal aorta. The celiac, aorticorenal, superior mesenteric, and inferior mesenteric
Synapse between pre and post synaptic sympathetic fibers occur in the prevertebral ganglia. Postsynaptic fibers pass from the prevertebral ganglia to the abdomainl viscera by means of the periarterial plexuses associated with the branches of the abdominal aorta.
Mainly involved in vasoconstriciotn and slowing of Gi motility
Discuss afferent pain impulses from abdominal viscera
Pass into the posterior root to the spinal sensory ganglia.
Stomach (foregut) t6-9
Small intestine through the trasnver colon (midgut) t8-12
Descending t12-l2
Sigmoid s2-s4
Discuss the parasympathetic innervation of the abdominal viscera
Consists of the following
- Anterior and posterior vagal trunks
- pelvic splanchnic nerves
- Abdomianl autonomic plexus
- intrinsic parasympathetic ganglia
The anterior and posterior vagal trunks are continuations of the left and right vagus nerve that emerge from the oesophageal plexus and pass through the oesophageal hiatus
The pelvic splanchinic nerves are distinct from other splanchnic nerves in that they
- have nothing to do with the sympathetic trunks
- derive directly form anterior rami of spinal nerve s2-4
- convey presynaptic parasympathetic fibers to the inferior hypogastric plexus
Presynaptic fibers terminate on the isolated and widely scattered cell bodies of postsynaptic neurons lying on or within the abdominal viscera consitituing intrinsic ganglia
Discuss distrubtion of parasympathetic input by the vagus
Vagal presynaptic parasympathetic and visceral afferent reflex fibers are conveyd by the vagus nerves extend to the lower oesophagus, stomach, small intestine indcluding the duodenum, ascending colon and most o fthe transverse.
Those conveyed by the pelvic splanchnic nerves are the descending and sigmoif parts of the colon, rectum and pelvic organs
Discuss the abdominal autonomic plexuses
Nerve networks consisting of both sympathetic and parasympathetic fibers which surround the abdominal aorta and its major branches.
- Superior mesenteric plexus has one median root and two lateral roots
- inferior mesenteric plexus has one median and one lateral root
Discuss the diaphragm
Main muscle of inspiration
Central parts descends during inspiration, lateral parts don’t as they are fixed
During inspiration the right dome can reach as high as the fifth rib and the left as high as the 5th intercostal space.
The muscular part of the diaphragm is situated peripherally with fibers that converge radially on the trifoliate central aponeurotic part, the central tendon.
The central tendon has nil bony attachment and is incomplete divided into three leaves resembling a wide clover leaf.
The caval opening through which the IVC passes through the central tendon
The muscular portion of the diaphragm forms a continuous sheet but is divided into three parts for description
1: sternal part: consisting of two muscular slips that attach to the posterior aspect of the xiphoid process
2: Costal part: consisting of wide muscular slips that attach to the internal surface of the inferior six costal cartilages and their adjoining ribs on each side; the costal parts form the right and left domes
3: lumbar part: arising from two aponeurotic arches the medial and lateral arcuate ligaments, and the three superior lumbar vertebrae; the lumbar part forms the right and left muscular crura that ascend to the central tendon
The crura of the diaphragm and musculotendinous bundles that arise from the anterior surfaces of the bodies of the superior three lumbar vertebrae, the anterior longitudinal ligament and the IV discs.
The right crus is large and longer
The oesophageal hiatus is a formation of the right crus even though it lies left of the midline
The right and left crus and the medial arcuate which unites them forms the aortic hiatus
The medial and lateral arcuate ligaments are thickening of fascia covering the psoas major and the quadratus lumborum
Discuss the vascular supply of the diaphragm
Superior surface is supplied by the pericardiacophrenic and musculophrenic arteries branches of the internal thoracic artery and the superior phrenic artery arising from the thoracic aorta
The arteies supplying the inferior surface are the internal phrenic nerve arising from either the abdominal aorta or the coeliac trunk
Venous drainage on the superior surface are the pericardiacophrenic and musculophrinc veins which empty into the internal thoracic venis and on the right side the superior phrenic vine which drains itno the iVC
Some veins from the posterior curvature drain into the azygos and hemiazygos veins
The right inferior phrenic vein usually opens into the ICV where as the left is double with once branching passing through the oesophageal hiatus to end in the IVC and the other joining the left suprarenal vein
Describe the lymphatic drainage of the diaphragm
The lymphatic plexuses on the thoracic and abdomainl surfaces of the diaphragm communicate freely, The anterior and posterior diaphragmatic lymph nodes are on the thoracic surface of the diaphragm. Lymph from these nodes drains into the parasternal, posterior mediastinal and phrenic nodes. Lymphatic from the abdominal side drain into the anterior diaphragmatic phrenic and superior lumbar lymph nodes.
Discuss the nerve supply to the diaphragm
Via the left and right phrenic nerves each arising from the anterior rami of C3-5 segments of the spinal cord and distributed to ipsilateral half of the diaphgragm. Also supplies sensory(pain and proprioception)
Peripheral parts of the diaphragm receive supply from the intercotal nerves (lower 6-7) and the subcostal nerves
Describe the diaphragmatic apertures
- Caval opening: T8: IVC and terminal branches of the right phrenic
- Eosophageal hiatus: T10: eosophagus, anterior and posterior vagal trunks, oeophageal branches of the left gastric vessel and lymphatics. The fibers of the left and right crus decussate inferior to the hiatus forming a sphincter. Superior and left of the aortic hiatus
- Aortic hiatus: t12 transmits the aorta and thoracic duct and sometimes the azygos and hemiazygos. Does not pierce the diaphragm and is unaffected by contraction of the same.
- Small apertures of the diaphragm which transmits lymphatic vessels from the diaphragmatic surface of the liver and the superior epigastric vessel.s
