Abdominal Viscera Anatomy PDF

13. Abdominal Viscera A: Abdominal Oesophagus, Stomach and Duodenum Oesophagus Muscular tube from the pharynx to the stomach designed for propulsion of food (peristalsis) Average diameter is 2cm About 25-30c...

13. Abdominal Viscera A: Abdominal Oesophagus, Stomach and Duodenum Oesophagus Muscular tube from the pharynx to the stomach designed for propulsion of food (peristalsis) Average diameter is 2cm About 25-30cm in an adult male o Slightly less in females and less than half of that in a new-born Parts of the oesophagus: 1. Cervical part o 1/5 of total length o Starts at lower border of cricoid cartilage o Descends anterior to C6 and C7 and extends into thoracic inlet 2. Thoracic part o Extends from T1 to T10 o Longest part o Extends to oesophageal hiatus within in the right crus of the diaphragm 3. Abdominal part o Shortest o About 1/6 of total length o Ends at cardial orifice of stomach § At the level of T11 § 2.5cm from the median plane § Behind the left 7th costal cartilage 1 Zaid Ganie  Sites of constriction of the oesophagus: 1. Cervical constriction (upper oesophageal sphincter) o 15cm from incisor teeth o Narrowest point o Partly due to the inferior constrictor muscle 2. Thoracic (bronchoaortic) constriction o At 22.5cm from incisors § Due to aortic arch seen anteroposteriorly o At 27.5cm from incisors § Due to crossing of left main bronchus seen laterally 3. Diaphragmatic constriction o At 37-40cm from incisors o Due to passing of the oesophagus through the oesophageal hiatus NB: Awareness of these constrictions is important when Passing instruments through the oesophagus into the stomach and Viewing radiographs of patients who are experiencing difficulty swallowing Course of the oesophagus: Median at its commencement opposite C6 Deviates slightly to left until C7 Returns to median plane at T5 Inclines to left & forward at T7 Enters abdomen & sharply deviates to left at T10 Joins stomach at T1 Neurovasculature and lymphatics: Arterial supply Venous drainage Lymphatics Innervation Recurrent laryngeal nn. Cervical Inferior thyroid aa. Inferior thyroid vv. Deep cervical nodes Cervical sympathetic trunk (from middle cervical ganglion via plexus around inferior thyroid aa.) Azygos v. Vagal trunk Oesophageal br. from Hemiazygos v. Tracheobronchial nodes Oesophageal plexus (above and below Thoracic descending thoracic aorta Accessory Posterior mediastinal lung root) Bronchial aa. hemiazygos v. nodes Greater splanchnic nn. from sympathetic trunk Vagal trunks (anterior and posterior) Abdominal Left gastric a. from coeliac trunk Azygos v. Left gastric nodes Greater splanchnic nn. and plexus Left inferior phrenic a. Left gastric v. coeliac nodes around left gastric and inferior phrenic aa. from thoracic sympathetic trunk 2  Stomach Most dilated part of the GIT between the oesophagus and small intestine Location: o Epigastric, umbilical and left hypochondriac regions o Dependent on contents and surrounding viscera o Can distend down to hypogastric region Shape: o J-shaped o Modified by changes in content and surrounding viscera o In obese- high and transverse o In asthenic- long and narrow Capacity: o Varies with age o 30ml at birth o 1L at puberty o 1.5L in adults o Twice normal capacity in full distension Parts of the stomach: 1. Cardia: o Surrounds the cardial orifice (superior inlet of stomach) o In supine position, the orifice lies: § Posterior to 6th left costal cartilage § 2-4 cm from median plane § At the level of T11 2. Fundus: o Dilated superior part related to the left dome of the diaphragm o Limited inferiorly by the horizontal plane of the cardial orifice o Cardial notch- between oesophagus and fundus o In supine position, the fundus lies: § Posterior to the left 6th rib § In the plane of the midclavicular line 3. Body: o Largest part 4. Pyloric: o Funnel shaped outflow region o Pyloric antrum- wider part leading to pyloric canal o Pyloric canal- narrower part o Pylorus- distal sphincter region of the pyloric part o In supine position, the pyloric part lies: § In the transpyloric plane § About 1.25cm from the midline Transpyloric plane: Midway between jugular notch superiorly and pubic crest inferiorly Transects the 8th costal cartilage and L1 vertebra 3  Curvatures of the stomach: Lesser curvature- o Forms the shorter concave right border of the stomach o Angular notch (incisure) § Most inferior part of the curvature § Marks the junction of the body and the pyloric part of the stomach § Lies just to the left of the midline Greater curvature- o Forms the longer convex border of the stomach (4-5 times longer) o Course: § Passes inferiorly to the left from the junction of the 5th intercostal space and the MCL § Curves to the right passing deep to the 9th/10th left costal cartilage § Continues medially to reach pyloric antrum o Covered by peritoneum and gives attachment to gastrosplenic ligament and greater omentum Interior of stomach: Gastric folds (rugae) diminish with distension Oesophageal opening and physiological sphincter at level of T11 Pyloric opening and anatomical sphincter at level of L1 o Identified by pre-pyloric vein of Mayo which runs vertically across its anterior surface Relations of stomach: Anterior- 1. Diaphragm 2. Spleen (upper and left parts of stomach) 3. Left lobe of liver 4. Anterior abdominal wall Posterior- 1. Diaphragm (left dome) 2. Omental bursa 3. Left kidney and suprarenal gland 4. Spleen and splenic artery 5. Pancreas 6. Transverse mesocolon and splenic flexure inferiorly 4 Arterial supply to stomach: 1. Left gastric Common hepatic 2. Right gastric Coeliac trunk Gastroduodenal 5. Right gastro-omental Splenic 3. Short gastric 4. Left gastro-omental Right and left gastric anastomose along lesser curvature Right and left gastro-omental anastomose along greater curvature Venous drainage: Short gastric Splenic vein Left gastro-omental Right gastro-omental Superior mesenteric vein Left gastric Hepatic portal vein Right gastric Innervation: Parasympathetic: o Anterior and posterior vagal trunks § Secretomotor to glands § Motor to muscles Sympathetic: o Coeliac plexus (T6-T9) § From greater splanchnic n. § Runs with gastric and gastro-omental aa. Lymphatic drainage: Vasomotor to blood vessels Superior 2/3 o Along right and left gastric vessels Pain fibres from muscles o To gastric nodes ® to aortic nodes Motor to pylorus for sphincteric constriction Right 2/3 of inferior 1/3 o Along gastro-omental vessels o To pyloric (subpyloric) nodes Left 1/3 of greater curvature o Along short gastric and splenic vessels o To suprapancreaticoduodenal nodes ® to aortic nodes 5  Duodenum Shortest, widest and most fixed part of small intestine Retroperitoneal except for proximal half of the superior part Extent: pylorus on the right to duodenojejunal flexure on the left o Flexure at the level of L2, 2-3cm from the left of the midline Shape: c-shaped with convexity to the right side and concavity enclosing the head of the pancreas Location: epigastric and umbilical regions Parts: superior, descending, inferior and ascending Parts of the duodenum and their relations: Common bile duct and pancreatic ducts open into descending part Duodenojejunal flexure is widened by suspensory muscle of the duodenum (ligament of Treitz) Anterior Posterior Medial Superior Inferior Superior (A&B) Peritoneum Bile duct Pylorus Neck of gallbladder Neck of 5cm Gallbladder Gastroduodenal a. pancreas Lies at L1 Liver-quadrate lobe Hepatic portal v. IVC Descending (C) Transverse colon & Right kidney (hilum) Head of pancreas Superior duodenum Inferior 8.5cm Mesocolon Renal vessels Pancreatic duct duodenum Lies at L1-L3 Small intestine Ureter Bile duct Psoas major Inferior (D) SMA and SMV Right psoas major SMA and SMV Ilium 7cm Small intestine IVC Head of uncinate Lies at L3 Aorta process of pancreas Right ureter Ascending (E) Root of mesentery Left psoas major SMA and SMV Body of pancreas Jejunum 5cm Jejunum Left margin of aorta Uncinate process Runs superomedially of pancreas (left to right) from L3-L2 Neurovasculature and lymphatics Venous drainage Lymphatic drainage Innervation Directly to hepatic portal vein Pancreaticoduodenal LN Sympathetic: Indirectly through Superior mesenteric LN Greater and lesser splanchnic Splenic v. plexuses SMV Parasympathetic: Vagus n. via coeliac and superior mesenteric plexuses Arterial supply Coeliac trunk Common hepatic a. Gastroduodenal a. Supraduodenal Superior pancreaticoduodenal a. Superior mesenteric a. Inferior pancreaticoduodenal a. 6  B: Liver and Gallbladder Liver Largest and heaviest gland Wedge-shaped or roughly triangular with dark reddish-brown colour Weight: 2.5% of adult body weight o Heavier in males o Relatively larger in foetuses and new-borns Functions: 1. Secretes bile 2. Synthesises proteins 3. Metabolism of all nutrients except fat 4. Stores glycogen 5. Destruction of RBCs and toxins Location: o Lies in the right upper quadrant- protected by the ribs and diaphragm o Deep to ribs 7-11 o Occupies right hypochondrium, epigastrium and may extend into left hypochondrium o Moves with the diaphragm § Palpable during deep inspiration in supine position Surfaces of the liver: Applied anatomy: Diaphragmatic and visceral surfaces separated by sharp inferior border The great vascularity of the liver 1. Convex diaphragmatic surface causes considerable haemorrhage o Formed by anterior, superior and part of the posterior surfaces in wounds of the live o Subphrenic recesses: Liver is prone to perforation from § Superior extensions of the peritoneal cavity fractures of the surrounding ribs Liver is a good site for secondary § Between the diaphragm and the anterior and superior aspects carcinoma from almost any other of the liver body site § Separated into right and left by falciform ligament o Anterior surface: § Diaphragm separates it from 6-10 costal cartilages on the right and 7-8 costal cartilages on the left o Superior surface: § Dome of diaphragm separates it from lung and heart § Bare area of the liver present on this surface Area not covered by visceral peritoneum § IVC runs posteriorly o Posterior surface § Against vertebral column 2. Concave visceral surface o Porta hepatis: § Transverse fissure for portal triad, hepatic nerve plexus and lymphatics o H-shaped right and left sagittal fissures § Right- groove for IVC and fossa for gall bladder § Left- fissure for the round ligament and fissure for ligamentum venosum 7  o Impressions and relations of the visceral surface: 1. Stomach- right side of anterior aspect 2. Pyloric area of stomach 3. Duodenum- superior part 4. Right transverse colon 5. Right colic flexure 6. Right kidney and suprarenal gland Peritoneal ligaments: Falciform ligament- to supra-umbilical anterior abdominal wall and diaphragm o Contains ligament teres hepatis- remnant of umbilical vein (round ligament) Triangular ligaments (right and left)- to diaphragm o Meeting points of coronary ligaments Coronary ligaments (superior and inferior layers)- to diaphragm o Sites of reflection of peritoneum Hepatogastric ligament- to stomach by the membranous portion of the lesser omentum Hepatoduodenal ligament- to duodenum by thickened free edge of the lesser omentum Hepatocolic ligament- liver to right colic flexure of transverse colon Lobes of the liver: Larger left lobe and smaller right lobe separated by falciform ligament and left sagittal fissure Transverse porta hepatis separates right lobe between right and left sagittal fissures into o Quadrate- anterior and inferior o Caudate- posterior and superior Functional segments: 8 segments each having its own branch of the hepatic artery, portal vein and bile duct Part Division Segment Lobe Posterior I Posterior segment caudate Left Left lateral II Left posterolateral Left III Left anterolateral Left medial IV Left medial Quadrate Right medial V Right anteromedial Right VI Right anterolateral Right Right lateral VII Right posterolateral VIII Right posteromedial Neurovasculature and lymphatics: Blood supply Venous drainage Lymph drainage Innervation Left and right hepatic aa. (20-25%) Left and right hepatic vv. Superficial vessels in subserosa areolar Hepatic plexus derived from Hepatic portal v. (75-80%) To IVC tissue drain via coeliac plexus - Hepatic - Accompanies hepatic a. - Coeliac and portal v. - Para-aortic lymph nodes - Sympathetic trunk via Into the thoracic duct coeliac ganglion and plexus Deep vessels end in nodes around IVC Vagal trunks 8  Gallbladder Piriform-shaped sac lying in its fossa on the visceral surface of the liver Length: 7-10cm Breadth: 3cm at widest Capacity: 30-50ml Function: storage, concentration and release of bile Parts of the gallbladder: Fundus o Wide blunt end projecting from the inferior border of the liver o At the tip of right 9th costal cartilage in the MCL o Anteriorly- anterior abdominal wall o Posteriorly- transverse colon Body o Main holding portion o Contacts the visceral surface of the liver, transverse colon and superior duodenum Neck o Directed towards the porta hepatis o Makes an s-shaped bend and joins the cystic duct o Hartmann’s pouch- small pouch projecting from the right wall of the neck § Not present in everyone Cystic duct: 3-4cm long Connects the neck of the gallbladder to the common hepatic duct Mucosa of the neck spirals into the spiral fold o Keeps the cystic duct open so that bile can o be diverted into the gallbladder when the distal end of the bile duct is closed o pass to the duodenum when the gallbladder contracts Neurovasculature and lymphatics: Blood supply Venous drainage Lymph drainage Innervation Cystic artery Cystic veins Hepatic and cystic lymph Around cystic artery from - from right hepatic a. - into liver directly or nodes coeliac plexus and vagus n. - variations in origin: - into hepatic vein or - right phrenic n. may carry o common hepatic a. - into veins draining upper pain caused by o gastroduodenal a. bile duct inflammation - supplies hepatic ducts and upper common bile duct accessory cystic a. - may arise from common hepatic a. 9  Biliary Ducts convey bile from the liver to the duodenum Hepatocytes Hepatocytes Bile canaliculi Bile canaliculi Interlobular biliary ducts Interlobular biliary ducts collecting bile ducts of intrahepatic portal triad collecting bile ducts of intrahepatic portal triad Right hepatic duct Left hepatic duct Common hepatic duct Cystic duct (Common) bile duct Bile duct: Forms in the free edge of the lesser omentum by union of common hepatic and cystic ducts Course: o Left of descending duodenum o Joins main pancreatic duct o Forms dilation- hepatopancreatic ampulla o Opens into the duodenum at the major duodenal papilla Blood supply: Cystic artery Proximal bile duct Right hepatic artery Middle bile duct Posterior superior pancreaticoduodenal a. Retroduodenal bile duct Gastroduodenal a. Venous drainage: Proximal and middle parts directly into liver Posterior superior pancreaticoduodenal v. drains distal part into hepatic portal vein Applied anatomy: Obstruction of duct system from gallstone formation (cholelithiasis) leads to pain and jaundice o Could also be caused by pressure from malignant tumours (pylorus and pancreas) Duplicated gall bladder with separate or a common cystic duct. Failure of canalization of bile duct congenital atresia or stenosis. Separate opening of common bile duct and pancreatic duct into the duodenum 10  C: Pancreas and Spleen Pancreas Soft, lobulated greyish-pink gland 12-15cm long and 60-100g in weight Location: o Epigastric and left hypochondriac region o Directed nearly horizontally across the posterior abdominal wall o Posterior to the stomach between the duodenal concavity and the hilum of the spleen o At vertebral levels L1 and L2 (transpyloric plane) Produces: o Exocrine secretion § Pancreatic juice from acinar cells § Enters the duodenum through the main and accessory pancreatic ducts o Endocrine secretions § Glucagon, insulin, somatostatin § From the islets of Langerhans Parts of the pancreas and their relations: Part Relations Head Anterior surface: Posterior surface: Lodged within the curve of duodenum Transverse colon, mesocolon, jejunum IVC and aorta Uncinate process projects from inferior part SMA across uncinate process Common bile duct Renal veins Right crus of diaphragm Neck Posteriorly: Springs from right upper portion of the front SMV joins splenic vein to form hepatic portal vein of head 2.5cm long Anteriorly: Posteriorly: Inferiorly: Superiorly: Surface- Surface- Surface- Border- Peritoneum Aorta Peritoneum Coeliac a. Omental bursa Origin of SMA Duodenojejunal & Splenic a. Body Border- Left crus of diaphragm Splenic flexure Hepatic a. Transverse colon Left suprarenal gland Jejunum Left kidney Border- Left renal vessels SMA&SMV Splenic vein Tail In contact with gastric surface of spleen and closely related to the splenic hilum Narrow Anterior to the left kidney 11 Pancreatic ducts: Main duct (of Wirsung): o Runs from tail to head o At the neck it turns caudally and dorsally to contact the bile duct o Hepatopancreatic ampulla (of Vater)- dilation where the bile duct meets the main pancreatic duct o Passes obliquely through the wall of the descending duodenum o Opens via a common orifice into the lumen 8-10cm from the pylorus o Sphincters: § Sphincter of the pancreatic duct around the terminal part of the pancreatic duct § Choledochal sphincter around the termination of the bile duct § Hepatopancreatic sphincter of Oddi around the hepatopancreatic ampulla Accessory (minor) duct of Santorini o Duct of the embryonic dorsal pancreas o Drains part of the head o Enters the duodenum 2cm above the main pancreatic duct o May or may not join the main duct Neurovasculature and lymphatics: Venous drainage Lymph drainage Innervation Directly into hepatic portal vein Pancreaticosplenic LN Coeliac and mesenteric plexuses Indirectly via splenic v. and SMV Coeliac LN Superior mesenteric LN Arterial supply Splenic a. Pancreatic branches (great, inferior, dorsal etc.) Coeliac trunk Common hepatic a. Gastroduodenal a. Superior pancreaticoduodenal a. Retroduodenal a. Superior mesenteric a. Inferior pancreaticoduodenal a. Applied anatomy: cancer of the head of the pancreas Often compresses and obstructs the bile duct and/or the hepatopancreatic ampulla Results in o Retention of bile pigments o Enlargement of gallbladder o Jaundice 12  Spleen Largest lymphoid organ Soft, highly vascular and dark purplish in colour covered with a layer of visceral peritoneum o Peritoneum covers the entire spleen except for the hilum Normal spleen is not palpable Functions in the immune response o Initially- lymphocyte proliferation o Subsequently- identification, removal and destruction of RBCs and platelets Location: o Left hypochondrium and epigastric regions o Between the fundus of the stomach, diaphragm and kidney o The spleen is mobile Shape: slightly curved wedge Size and weight vary at different periods in life o 12x7x3 cm o 150g Surface anatomy: Long axis lies in line of 9th, 10th and 11th left ribs Posterior end is 4cm from mid-dorsal line opposite the spine of T10 Anterior end reaches midaxillary line Relations of the spleen: Anterior- stomach Posterior- left part of diaphragm o separating it from the pleura, lung and ribs 9-11 Inferior- left colic flexure Medial- left kidney Hilum- o Tail of pancreas o Splenic vessels, nerves and nodes Surfaces and borders: Diaphragmatic surface is convex Anterior and superior (notched) borders are sharp Posterior (medial) end and inferior borders are rounded Ligaments of spleen: Lienorenal (splenorenal) o Contains splenic vessels Gastrosplenic o Contains short gastric and left gastro-omental vessels Phrenicocolic o Acts as a wedge for inferior border Neurovasculature and lymphatics Arterial supply Venous drainage Lymphatic drainage Innervation Splenic artery from coeliac trunk 5-6 tributaries unite to form a single splenic vein Splenic nodes Coeliac plexus Tortuous course Splenic v. joins SMV to form hepatic portal v. Each segment has its own br. End artery: Obstruction leads to segmental infarction 13  D: Jejunum, Ileum and Large Intestine Small Intestine Extent: pylorus to ileocecal valve Parts: duodenum, jejunum and ileum Jejunum and ileum o are 6-7m long o Diminish in diameter towards termination o Are completely intraperitoneal Jejunum: proximal 2/5 after duodenum from duodenojejunal flexure Ileum: distal 3/5 to ileocecal junction Locations: o Jejunum- left upper quadrant o Ileum- right lower quadrant Distinguishing characteristics of jejunum and ileum in the living body Characteristics Jejunum Ileum 1 Colour Deeper red Paler pink 2 Calibre 2 –4 cm 2 –3 cm 3 Wall Thick and heavy Thin and light 4 Vascularity Greater Less 5 Vasa recta Long Short 6 Arcades A few large loops Many short loops 7 Fat in mesentery Less More 8 Circular folds Large, tall and Low and sparse, (plica circulares) closely packed absent in distal part 9 Lymphoid nodule Few Many (Peyer’s patches) Mesentery of the small intestine: Extent: o from the duodenojejunal junction on the left of L2 to the ileocolic junction o to ileocolic junction and the right sacro-iliac joint contents: o superior mesenteric vessels o lymph nodes o variable amount of fat o autonomic nerves Neurovasculature and lymphatics: Blood supply Venous drainage Lymph drainage Innervation Superior mesenteric a. Superior mesenteric v. Juxta-intestinal lymph nodes ® Posterior vagal trunk - jejunal and ileal br. mesenteric lymph nodes ® Thoracic splanchnic - br. form arterial arcades superior mesenteric lymph nodes. nerves (T8-T10) through - arcades give rise to vasa recta coeliac ganglia and Terminal ileum ® ileocolic lymph superior mesenteric plexus nodes. 14  Large Intestine Parts: o caecum and appendix o ascending, transverse, descending and sigmoid colon o rectum and anal canal 1.5m long More fixed in position than small intestine and has a larger internal diameter Features: Omental appendices: o Small fat-filled sacs of peritoneum o Not in caecum, vermiform appendix and rectum Taenia coli: o Longitudinal muscle fibres arranged in 3 bands from base of appendix 1. Mesocolic taenia- transverse and sigmoid mesocolons attach 2. Omental taenia- omental appendices attach 3. Free taenia o Not in appendix and rectum Haustra/sacculations: o Caused by taenia coli being shorter than the other coats Surface anatomy: Ascending colon: o upward through right lumbar region, lateral to right MCL. Right colic flexure: o in upper right angle of intersection of subcostal line & right MCL. Transverse Colon: o crosses abdomen through umbilical & epigastric regions o lower border at level above umbilicus o upper border just below greater curvature of stomach Descending colon o courses down through left lumbar region lateral to left MCL as far as iliac crest Left colic flexure o in upper left angle of intersection between left MCL & transpyloric lines. Sigmoid Colon o line is from end of descending colon to left MCL at level of ASIS 15 Caecum: Dilated pouch Continuous superiorly as ascending colon Extends caudally below ileocecal valve Location: o right iliac fossa above inguinal ligament Completely covered by peritoneum. Variable shape and relatively stable. Dimension: 6-7 cm in length and breadth. Ileocecal valve: o Has an upper and a lower lip which fuse at either side to form frenulum of the valve. o Suggested to prevent reflux into ileum Vermiform appendix: Long and narrow worm like tube about 8 cm Arises from posteromedial wall of caecum 2 cm below ileocecal valve. Longer in infants than in adults. Fixed by meso-appendix which contains appendicular artery Has a small canal which communicates with caecum by an orifice placed below and behind the ileocecal opening Variable position o Retrocecal- most common o Subcecal o Pre-ileal or retro-ileal The 3 taeniae coli converge on the base of the appendix o Easy guide to it in surgery Surface marking: o Base of appendix is 2/3 the way from umbilicus to right ASIS § McBurney’s point Applied anatomy: appendicitis o Obstruction of lumen of appendix is the usual cause o Acute infection of appendix can cause thrombosis of appendicular artery leading to quick development of gangrene and subsequent perforation and then peritonitis o Referred pain: § region around umbilicus (T10 spinal nerve) Ascending colon: Narrower than caecum Extent: Ileocecal orifice to right colic (hepatic) flexure Location: right lumbar and right hypochondriac regions. Peritoneum covers anterior and lateral surfaces Transverse colon: Longest Extent: from right colic flexure crosses umbilical region into left hypochondriac region and bends caudally (left colic/splenic flexure) Most mobile Completely invested in peritoneum Transverse mesocolon extends to pancreas Descending colon Extent: from left colic flexure to end in the sigmoid colon at pelvic inlet Covered by peritoneum on the anterior and lateral surfaces 16  Sigmoid colon: From the pelvic brim, crosses the sacrum and then curves to midline at S3 to enter the rectum Forms a loop hanging into the pelvis with sigmoid mesocolon. Position and shape vary based on its length o Freedom of sigmoid mesocolon and distension of rectum and uterus. Blood supply to large intestine: Artery Branch Distribution Intestinal (15-18) Jejunum and ileum Proximal 2/3 of Middle colic transverse colon Superior mesenteric Right colic Ascending colon Ileum, caecum and Ileocolic ascending colon Appendicular Appendix Distal 1/3 of transverse, Left colic and descending colon Inferior mesenteric Descending and Sigmoid (3-4) sigmoid colon Superior rectal Proximal rectum Venous drainage: Superior and inferior mesenteric vv. Innervation: Midgut derivatives: o Coeliac and superior mesenteric plexuses Hindgut derivatives: o Lumbar part of sympathetic trunk o Superior hypogastric plexuses Lymphatics: Part of colon Drained by Caecum and appendix ileocolic LN Ascending colon epiploic and paracolic LN Transverse colon middle colic LN Descending and sigmoid colon intermediate colic LN Applied anatomy: Colonoscopy- to view interior of the colon o Removal of biopsy for analysis and clumps of cells (polyps). o Colorectal cancer is the 4thmost common cancer in South Africa Volvulus of sigmoid colon with complication of loss of blood supply leading to necrosis 17  E: Kidneys, Ureters and Suprarenal Glands Kidneys Reddish brown, bean-shaped Location: o posterior abdominal wall o each side of vertebral column from T12 to L3 Retroperitoneal Right kidney usually lower than left Left kidney is narrower, longer and closer to midline Transpyloric plane passes through superior part of right kidney and through inferior part of hilum of left kidney. Dimensions: Superior o Length: 11cm o Breadth: 6cm o Thickness: 3cm A Weight: 150g in males and 135g in females Posterior V Anterior P Surfaces and borders: Anterior and posterior surfaces Superior and inferior poles Inferior Medial and lateral margins o Medial margin contains the hilum § Anterior to posterior: vein, artery, pelvis § Superior to inferior: artery, vein, pelvis Relations of the kidneys: Anterior relations Posterior relations Right kidney Left kidney Both kidneys 1. Suprarenal gland 1. Suprarenal gland 1. Ribs 11&12 2. Liver 2. Stomach 2. Diaphragm 3. Duodenum (2nd part) 3. Spleen 3. Muscles: 4. Right colic (hepatic) flexure 4. Pancreas - Psoas major 5. Jejunum 5. Descending colon - Quadratus lumborum 6. Jejunum - Transversus abdominis 4. Neurovascular structures - Subcostal nn. and vessels - Iliohypogastric nn. - Ilioinguinal nn. Renal fascia and fat: Renal fascia: from subserous extraperitoneal fascia o Splits into § Anterior layer- continues over renal vessels and aorta to join opposite side § Posterior layer- in front of fascia on quadratus lumborum and psoas major to opposite side Perirenal (perinephric) fat: mass of adipose tissue between surface of kidney (capsule) and renal fascia (space of Gerota) Pararenal (paranephric) fat: considerable quantity of fat lying behind renal fascia o Fibrous and more in new-born than in adults 18  Structure of the kidney: Renal capsule: o Tough fibrous tissue which is easily removable except during disease Hilum of the kidney: o Deep vertical slit o Passes renal vessels, lymphatics and nerves o Continuous internally with the renal sinus Renal cortex and medulla: o Continuous band of pale tissue completely surround the renal medulla o Renal columns- extensions of the renal cortex into the inner aspect of the kidney Renal pyramids: o Discontinuous aggregations of triangular-shaped tissue divided by the renal columns o Apices are directed toward the renal sinus o Renal papilla- apical projection containing openings of papillary ducts into minor calices Major calyx: o Uniting of many minor calices o 2-3 major calices unite to form the renal pelvis Applied anatomy: Horseshoe-shaped kidney Pelvic kidney Neurovasculature and lymphatics: Blood supply Venous drainage Lymphatic drainage Innervation Renal aa. Renal vv. Lymph vessels to lateral Renal plexus - from abdominal aorta - drain into IVC aortic lymph nodes - level of L1/L2 IV disc - left renal v. tributaries: - right is longer than left 1. left phrenic - Branches to 5 segments: 2. left testicular/ovarian 1. superior (apical) 3. left suprarenal vv. 2. anterosuperior 3. anteroinferior 4. inferior 5. posterior Relations of renal arteries and veins: Left renal artery: o Anteriorly- left renal v., splenic v., inferior mesenteric v. and body of pancreas Right renal artery: o Anteriorly- IVC, right renal v., head of pancreas and descending duodenum Left renal vein: o Crosses anterior to aorta just below SMA o Opens into IVC above right renal vein Right renal vein: o Lies anterior to renal artery 19  Ureters Highly distensible thick-walled tubes 25-30cm long and 3mm in diameter Extent: from the renal pelvis at the level of L1 to base of urinary bladder Retroperitoneal in its entire course Points of constriction: 1. At the junction of ureter and renal pelvis 2. At the brim of the pelvic inlet 3. At the ureterovesical junction Blood supply Lymphatic drainage Upper end- Upper end- Renal aa. Lateral aortic (lumbar) LN Middle part- Middle part- Superior & inferior vesical aa. LN around common iliac vessels Testicular/ovarian aa. Common iliac aa. In pelvis- Inferior part- Internal iliac aa. LN around internal and external iliac vessels Innervation Venous drainage Lesser and lower splanchnic nn. Veins correspond and follow arteries Renal plexus Aortic plexus Superior and inferior mesenteric plexuses Course: Abdominal course Pelvic course (see pelvic viscera) Male and female Male female Runs on medial side of psoas major Anterior to internal iliac a. Anterior to internal iliac a. Crosses genitofemoral nerve Medial to obturator, inferior vesical Forms posterior boundary of ovarian Crossed by gonadal vessels & middle rectal aa. fossa Right ureter: Turns at lower part of sciatic notch Closely related to uterine a. at medial part at origin- overlapped by descending to reach lateral end of bladder of broad ligament duodenum Anterior to seminal vesicles - Uterine a. lies above and crosses Courses on the right of IVC Crossed by vas deferens above & in anteriorly on the medial side Crossed anteriorly by font from lateral to medial Runs medially and anteriorly on the lateral - right colic and ileocolic vessels aspect of cervix of uterus and upper - mesentery and terminal part of ileum vagina Left ureter: Crossed by left colic vessels and sigmoid and sigmoid mesocolon Applied anatomy: Kidney stones may descend and lodge at points of constriction o Leads to dilation in ureter above the stones o Dilation of renal pelvis and calices lead to hydronephrosis o Results in severe pain (renal colic) and urinary retention. Congenital anomaly: double ureter 20  Suprarenal Glands Endocrine glands that secrete o Corticosteroids o Androgens o Catecholamines (adrenaline and noradrenaline) Location: lateral lumbar regions on the superomedial aspect of the kidneys Shape: o Right suprarenal gland- pyramidal o Left suprarenal gland- crescent-shaped Covered by renal fascia Attached to the crura of the diaphragm Separated from the kidneys by a thin septum Parts of the suprarenal glands: Suprarenal cortex: o Derived from the mesoderm o Secretes corticosteroids and androgens Suprarenal medulla: o Derived from neural crest cells o Secretes catecholamines Hilum: o Veins and lymphatics exit here § Arteries and nerves enter at many sites Relations of the suprarenal glands: Kidney Right crus of diaphragm Right suprarenal gland IVC Liver Kidney Left crus of diaphragm Left suprarenal gland Spleen Stomach Pancreas From right to left IVC Structures in between the medial Right crus of diaphragm borders of the suprarenal glands Coeliac ganglion Coeliac trunk Superior mesenteric a. Left crus of diaphragm Blood supply Venous drainage Lymphatic drainage Innervation 1. Superior suprarenal aa. Right suprarenal v. Lateral lumbar LN Coeliac and splanchnic nerves From inferior phrenic aa. To IVC Sympathetic fibres to chromaffin cells in suprarenal medulla. 2. Middle suprarenal aa. From abdominal aorta Left suprarenal v. 3. Inferior suprarenal aa. To left renal v. From renal aa. Referred pain from abdominal viscera: 21