© 2009 Mark Tuttle

Anterior Abdominal Wall and Inguinal Canal Learning Objectives – 1/5/09 [LANE]

  1. Define the boundaries of the abdominal cavity and the skeletal components related to the abdominal wall.
  2. Boundaries:
  3. Superior:Diaphragm
  4. Anterior:Aponeuroses
  5. Inferior:Superior pelvic aperture (imaginary)
  6. Posterior:Anterior longitudinal ligament of vertebral bodies
  7. Skeletal components
  8. Lumbar vertebrae
  9. Lower ribs
  10. Pubic bones
  11. Iliac crest
  12. Describe the major surface landmarks of the anterior abdominal wall.
  13. Linea semilunaris:On the lateral side of each rectus abdominus muscle
  14. Umbilicus:Remnant of the umbilical cord
  15. Linea alba:“happy trail.” Medially between rectus abdominal mm.
  16. Describe the lines and planes that are used to divide the abdomen into quadrants and regions.
  17. Quadrants
  18. Dividers
  19. Transumbilical plane (TUP)
  20. IV disk L3/L4
  21. Median plane (follows linea alba)
  22. Regions (4)
  23. Right upper quadrant (RUQ)
  24. Left upper quadrant (LUQ)
  25. Right lower quadrant (RLQ)
  26. Left lower quadrant (LLQ)
  27. Regions
  28. Dividers
  29. Mid-clavicular lines (2):Middle of clavicle down
  30. Subcostal plane:Tangent to lowest ribs (L2)
  31. Transtubercular plane:Midway between the upper transverse and the upper border of the symphysis pubis. Between iliac tubercles. (L5)
  32. Regions (9)
  33. Epigastric
  34. Right/Left hypochondriac
  35. Umbilical
  36. Right/Left lumbar
  37. Hypogastric
  38. Right/left inguial
  39. Other planes
  40. Transpyloric:L1, just above subcostal at L2
  41. Interspinous plane:Connects right/left ASIS, just above transtubercular
  42. Describe the attachments, orientations, relative positions, actions, and fascia of the four major abdominal muscles.
  43. External oblique
  44. Attachment
  45. 5th-12th ribs, inferiorly
  46. (Linea alba)
  47. Pubic tubercle
  48. Anterior ½ of iliac crest. “jumps across” inguinal ligament
  49. Orientation
  50. Like a “V”, or “hands in pockets”
  51. Relative position
  52. Superior lateral, membranous tendon inferior medial
  53. Action
  54. Compress abdominal contents
  55. Innervation
  56. Ventral rami T7-T12 (Thoracoabdominal nn.) +/- L1
  57. Fascia
  58. Superficial:
  59. Camper’s: Fatty (superficial) layer of superficial fascia
  60. Scarpa’s: Membranous (deep) layer of superficial fascia
  61. Deep fascia
  62. Deep:
  63. Deep fascia
  64. Internal oblique
  65. Attachment
  66. Thoracolumbar fascia
  67. Anterior 2/3 of iliac crest
  68. Inginal ligament (lateral ½)
  69. Lower ribs
  70. Orientation
  71. Upside-down “V”
  72. Relative position
  73. Inferior lateral, membranous tendon superior medial
  74. Action
  75. Unilateral: same side rotation/bending
  76. Innervation
  77. Ventral rami T7-T12 (Thoracoabdominal nn.) +/- L1
  78. Fascia
  79. Superficial/Deep:Deep fascia
  80. Transverse oblique
  81. Attachment
  82. Ribs/costal muscle
  83. Thoracolumbar fascia
  84. Iliac crest
  85. Lateral 1/3 of inguinal ligament
  86. Important b/c it does NOT contribute a layer to the spermatic cord
  87. Orientation
  88. Horizontal
  89. Relative position
  90. Lateral, membranous medial
  91. Action
  92. Raise abdominal pressure
  93. Innervation
  94. Ventral rami T7-T12 (Thoracoabdominal nn.) +/- L1
  95. Fascia
  96. Superficial: Deep
  97. Deep:Transversalis fascia
  98. Rectus Abdominus
  99. Attachment
  100. Costal cartilage of ribs 5-7
  101. Xyphoid process
  102. Pubic crest
  103. Orientation
  104. Vertical
  105. Relative position
  106. Segmented, with 4 sets of membranous aponeurosess
  107. Action
  108. Flexes trunk, compresses abdomen
  109. Innervation
  110. Ventral rami T7-T12 (Thoracoabdominal nn.) +/- L1
  111. Fascia
  112. Above arcuate line:
  113. Superficial/Deep:Internal oblique aponeurosis
  114. At/below arcuate line:
  115. Superficial:All abdominal aponeuroses
  116. Deep:Perietal peritoneum
  117. Define the blood supply, nerve supply, fascial layers, muscle layers, extraperitoneal fat, and parietal peritoneum of the anterior abdominal wall. How do these relate to the various surgical approaches to the abdominal cavity?
  118. Blood supply
  119. Superior
  120. Internal thoracic a.
  121. Musculophrenic a. branches laterally along subcostal angle
  122. Superior epigastric a. branches medially along rectal sheath
  123. Inferior
  124. External Iliac a.
  125. Inferior epigastric a. branches superior medial. Supplies more of rectus abdominus than superior epigastric because it is deep.
  126. Deep circumflex iliac a. branches superior medial
  127. Femoral a. continuation inferior to inguinal ligament
  128. Superficial epigastric a. branches superior medial
  129. Superficial circumflex iliac a. branches superior lateral along iliac crest superficially
  130. Lateral
  131. Intercostal aa. Even those of false ribs
  132. Subcostal a.
  133. Nerve supply
  134. Pathway:
  135. Between internal oblique mm. and transverse abdominis mm., pierce the rectus sheath to supply rectus ab. Mm. + provide anterior cutaneous branches
  136. Thoracoabdominal nn. (T7-T11)
  137. Cutaneous innervation separately of medial/lateral portions
  138. Iliohypogastric n. (L1) supplies mons pubis
  139. Ilioinguinal n. (L1) supplies scrotum/labia majora
  140. T10 supplies of umbilicus
  141. T5 supplies skin over xyphoid process
  142. Surgical approaches
  143. General goals
  144. Try not to transect arteries/nerves
  145. Use “Gridiron technique” in appendix surgery with McBurney’s point
  146. Landmarks
  147. Subcostal:outdated way for spleen surgery
  148. Median:linea alba
  149. Paramedian:just lateral to linea alba
  150. Super pubic:just above mons pubis, used in C-sections
  151. McBurney’s point
  152. Line between ASIS and umbilicus
  153. 1/3 of the way from ASIS to umbilicus
  154. Used for appendix surgery
  155. Describe the configuration of the anterior and posterior walls of the rectus sheath superior and inferior to the arcuate line.
  156. Superior to the arcuate line, the internal oblique aponeurosis surrounds the abdominus rectus
  157. Inferior to the arcuate line, the internal oblique aponeurosis is only superficial to the abdominus rectus since it pierces it
  158. Define the inguinal canal, including the location of the deep and superficial inguinal rings.
  159. Know the structures forming the walls of the inguinal canal.
  160. Superficial inguinal ring
  161. Medial Crus
  162. Lateral Crus
  163. Intercrural fibers (not very pronounced in most cadavers)
  164. Borders:
  165. Anterior:External oblique
  166. Posterior:Internal oblique/conjoint tendon
  167. Superior:Internal oblique
  168. Inferior:Inguinal ligament
  169. Define the function and mechanics of the inguinal canal.
  170. Route of passage for the testes from posterior abdominal wall to scrotum
  171. Contains the spermatic cord in males and the round ligament in females
  172. Describe the contents of the inguinal canal. How do these differ between the sexes?
  173. Males: spermatic cord, (gubernaculums)
  174. Females: round ligament
  175. Describe the borders of the inguinal triangle (Hasselbach’s Triangle).
  176. rectus abdominis muscle (medially)
  177. inguinal ligament (inferiorly)
  178. inferior epigastric vessels (superior and laterally).
  179. Define the anatomy and relationships of the:
  180. Process vaginalis
  181. Portion of peritoneal cavity that “follows” the testes as they descent. Normally is obliterated, but can be patent in adults.
  182. Spermatic cord
  183. Fascia layers
  184. External spermatic fascia
  185. Cremasteric fascia
  186. Internal spermatic fascia (continuous with transversalis fascia)
  187. Contents
  188. Ductus (Vas) deferens
  189. Testicular arvery, artery of Vas
  190. Pampiniform plexus of veins
  191. Helps cool temperature in testicles
  192. Lymph vessels
  193. Nerves
  194. Epididymus
  195. Narrow, tightly-coiled tube connecting the efferent ducts from the rear of each testicle to its vas deferens.
  196. Storage of sperm
  197. Cremaster muscle
  198. Originates from the internal oblique
  199. Surrounds the testes
  200. Helps regulate testes temperature to optimal for spermatogenesis
  201. Testes
  202. Site of spermatogenesis
  203. Consist of seminiferous tubules
  204. Scrotum
  205. Surrounds the testes
  206. Layers
  207. Skin
  208. Tunica dartosDartos fascia/muscle
  209. Colles’ fascia and dartos m. (smooth m.)
  210. External spermatic fasciaExternal oblique
  211. Cremaster muscle/fasciaInternal oblique
  212. Internal spermatic fasciaTransversalis fascia
  213. Tunica vaginalis (parietal/visceral)Peritoneum
  1. Describe the coverings of the spermatic cord and their role in the descent of the testes during development. How do these layers relate to the coverings of the scrotum?
  2. Many of the layers of the testes are continuous with analagous layers in the spermatic cord. However, the tunica vaginalis of the scrotum is a remnant of the peritoneum which is sealed off from the testes in normal adults
  3. Chart the blood supply and lymphatic drainage of the testis. How do they differ from that of the scrotum?
  4. Testes
  5. Blood:Testicular arteries
  6. Lymphatic:Inguinal Nodes
  7. Scrotum
  8. Blood:Anterior/posterior scrotal arteries
  9. Lymphatic:Deep lumbar nodes
  10. What is an inguinal hernia? What features distinguish a direct from an indirect inguinal hernia?
  11. Direct
  12. Through the inguinal triangle
  13. Transversalis fascia forms hernia sac
  14. Occurs medially to epigastric artery
  15. Less common than indirect hernias
  16. Indirect
  17. Through the deep/superficial inguinal rings
  18. Covered by all three layers of spermatic cord
  19. Remains of the process vaginalis forms the hernia sac
  20. 20x more common in males than females
  21. More common in younger people

Peritoneum and Major Vessels -1/6/2009 [LANE]

  1. Define the peritoneum and peritoneal cavity.
  2. Peritoneum
  3. Large, thin, transparent sheet of serous membrane which lines the walls of the abdominopelvic cavity and is reflected onto the viscera
  4. Peritoneal cavity
  5. Potential space between adjacent layers of peritoneum usually containing a small amount of fluid
  6. Understand what distinguishes parietal from visceral peritoneum.
  7. Parietal peritoneum lines the abdominal and pelvic walls
  8. Visceral peritoneum covers abdominal and pelvic organs
  9. Describe the shape and extent of the peritoneal cavity
  10. Know what the borders of the greater and lesser sac are.
  11. Lesser sac borders
  12. Anterior
  13. Lesser omentum
  14. gastrocolic ligament
  15. Inferior
  16. Trasverse mesocolon
  17. Superior
  18. Caudate lobe of liver
  19. Posterior
  20. Pancreas
  21. Aorta
  22. Celiac trunk
  23. Splenic a. and v.
  24. Gastrosplenic fold
  25. Left suprarenal gland
  26. Left kidney
  27. Right
  28. Liver
  29. Duodenal bulb
  30. Left
  31. Spleen
  32. Gastrosplenic ligament
  33. Greater sac borders
  34. Everything else within the peritoneum
  35. Describe the components of the greater and lesser omentums.
  36. Greater Omentum
  37. Attaches the stomach (along the greater curvature) to the posterior abdominal wall.
  38. Subdivided into 3 ligaments: (PCS)
  39. Gastrophrenic
  40. Gastrosplenic
  41. Gastrocolic
  42. Lesser Omentum
  43. Attaches the stomach (along the lesser curvature) to the liver.
  44. Subdivided into 2 ligaments:
  45. Hepatogastric
  46. Hepatoduodenal
  47. Know what forms the borders of the epiploic foramen. What spaces does it connect?
  48. It connects the greater and lesser sacs
  49. Also known as the Foramen of Winslow
  50. Borders:
  51. Anterior
  52. Hepatoduodenal ligament
  53. Posterior
  54. Peritoneum covering the inferior vena cava
  55. Superior
  56. Peritoneum covering the caudate lobe of the liver
  57. Inferior
  58. Peritoneum covering the duodenum/proper hepatic a.
  59. Know what organs and structures within the abdomen are intraperitoneal (peritoneal) and which are primarily and secondarily retroperitoneal?
  60. Primarily retroperitoneal
  61. Esophagus
  62. Suprarenal glands
  63. Kidneys
  64. Rectum
  65. Secondarily retroperitoneal
  66. Pancreas
  67. Duodenum (except for superior portion)
  68. Ascending colon
  69. Descending colon
  70. Intraperitoneal
  71. Everything else
  72. Be able to describe and give examples of peritoneal pouches, folds, recesses and gutters.
  73. Folds
  74. Lateral umbilical fold (2) (inferior epigastric)
  75. Medial umbilical fold (2) (obliterated umbilical a.)
  76. Median umbilical fold (1) (urachus)
  77. Recesses
  78. Subphrenic recess
  79. Between liver and diaphragm
  80. Superior recess of omental bursa
  81. Posterior part of liver
  82. Part of the lesser sac
  83. Borders the greater sac via the coronary ligaments
  84. Inferior recess of omental bursa
  85. Between stomach and transverse colon
  86. Pouches (pouch of peritoneum formed by peritoneal folds or ligaments)
  87. Rectovesical pouch
  88. Everything eventually drains here
  89. Hepatorenal pouch
  90. Gutters
  91. Right paracolic gutter
  92. Left paracolic gutter
  93. Spaces
  94. Supracolic compartment
  95. Infracolic compartment
  96. Right infracolic space
  97. Leaks can stay localized here for a while
  98. Bordered by mesentery
  99. Left infracolic space
  100. Distinguish between mesentery, mesocolon, greater omentum, lesser omentum and the various peritoneal ligaments.
  101. Mesocolon
  102. Transverse + Sigmoid  sections of colon that are intraperitoneal
  103. Greater omentum
  104. Hangs down from front of stomach
  105. Gastrophrenic + gastrosplenic + gastrocolic ligaments
  106. Lesser omentum
  107. Between stomach and liver
  108. Hepatogastric + hepatoduodenal ligaments
  109. Describe the causes and relations of the peritoneal reflections located on the anterior abdominal wall.
  110. Lateral umbilical folds (L + R)
  111. Houses the inferior epigastric artery
  112. Medial umbilical folds (L + R)
  113. Houses the obliterated umbilical artery
  114. Median umbilical fold
  115. Houses remnant of urachus, anembryological canal connecting the urinary bladder of the fetus with the allantois
  116. List the three unpaired branches of the abdominal aorta. Know the terminal branches of these main arteries.
  117. Splenic a.
  118. Short gastric aa.
  119. Left gastro-omental a. (gastropiploic) (on the greater curvature)
  120. Pancreatic a.
  121. Posterior gastric a. (60-80% of people)
  122. Proper hepatic a.
  123. Right gastric a.
  124. Left hepatic a.
  125. Right hepatic a.
  126. Cystic a.
  127. Gastroduodenal a.
  128. Supraduodenal a.
  129. Superior pancreatocoduodenal a.
  130. Right gastro-omental a. (gastroepiploic) (on the greature curvature)
  131. Describe the venous drainage from the abdominal viscera. What is the hepatic portal system?
  132. Begins at the venous ends of capillaries in the organs of the GI tract and ends at the venous sinusoids in the liver
  133. Formed bythe joining of the plenic vein with the superior mesenteric vein
  134. Inferior mesenteric vein usually joins the splenic vein
  135. NO VALVES in portal vein
  136. What is a portal-systemic anastomoses? Where do four major portal-systemic anastomosis occur in the body and what is the clinical significance of varicosities at these sites
  137. Esophageal varices
  138. Portal:Esophageal branch of left gastric v.
  139. Systemic:Esophageal branch to Azygous v.
  140. Anorectal varices
  141. Portal:Superior rectal branch of inferior mesenteric v.
  142. Systemic:Middle and inferior rectal to internal iliac v.
  143. Caput medusa
  144. Portal:Paraumbilical (in falciform ligament) branch of portal
  145. Systemic:Superior and inferior epigastric vv.
  146. Retroperitoneal varices (Veins of Retzius)
  147. Portal:Colic, duodenal, and pancreatic vv.
  148. Systemic:Lumbar and renal vv. to inferior vena cava

GI Tract and Associated Organs - Lane

  1. Abdominal part of esophagus
  2. Comes through the diaphragm at T8
  3. Stomach:
  4. Cardiac and pylorus orifices
  5. Cardiac orifice is at the top of the stomach at the gastroesophageal junction in the cardia region
  6. There are no chief cells in the cardiac region
  7. The pyloric orifice lies at the distal part of the stomach, part of the gastric sphincter
  8. Relation with greater and lesser omentum
  9. The greater omentum takes its origin along the greater curvature of the stomach
  10. Attaches the stomach to the posterior abdominal wall
  11. Composed of Gastrophrenic, gastrosplenic, and gastrocolic ligaments
  12. The lesser omentum takes origin along the lesser curvature of the stomach and attaches to the liver
  13. Composed of hepatogastric and hepatoduodenal ligaments
  14. Anterior and posterior surfaces
  15. On the posterior surface of the stomach runs the splenic artery off of the celiac trunk and in 60-80% of people
  16. Fundus and cardinal notch
  17. Fundus is the most superior part of the stomach. It ascends above the gastricesophageal junction. Usually there is an air bubble here.
  18. The cardial notch is the region immediately superior to the gastroesophageal junction
  19. Body and angular incisures
  20. The body of the stomach is below the Cardia and the Fundus
  21. The angular incisures divides the body from the pyloric antrum, it is clearly evident in a deflated stomach
  22. Pyloric antrum
  23. Distal to the gastric body is the pyloric antrum
  24. Pylorus, pyloric sphincter, pyloric canal
  25. The pyloric canal is a narrowing of the stomach approaching the pyloric sphicter
  26. Mucous membrane appearance, gastric folds (rugae)
  27. Rugae are oriented in the direction of flow
  28. Muscles of stomach wall
  29. 3 layers whereas the rest of the GI is only 2
  30. Oblique, circular, longitudinal
  31. Describe relations of stomach with adjacent structures.
  32. Right side: spleen
  33. Above: diaphragm and liver
  34. Left: liver
  35. Behind: pancreas
  36. Below: transverse colon
  37. Describe the blood supply of the stomach.
  38. The stomach is supplied by the right and left gastric arteries, (posterior gastric artery), and by the right and left gastro-omental arteries
  39. Small Intestine:
  40. Identify and distinguish the 3 major divisions of the small intestine: Duodenum, Jejunum, and Ilium. Note the major and minor doudenal papillae
  41. The duodemum is the most proximal part of the intestine, connecting to the stomach.
  42. The duodenum’s transition to jejunum occurs at the suspensetory ligament of the duodenum (Ligament of Treitz)
  43. There is no clearly defined border between the jejunum and the ileum, but you can tell the difference between the two regions based on structure
  44. Jejunum
  45. Thicker wall
  46. Smaller number of arcardes, longer vasa recta, poorer anastomoses
  47. Less fat
  48. Numerous plicae
  49. Few Peyer’s patches
  50. Ileum
  51. Thinner wall
  52. Larger number of arcades, shorter vasa recta, better anastomoses
  53. More fat
  54. Poorly defined plicae
  55. Many Peyer’s Patches
  56. Describe their locations and relationships to other abdominal structures including mesenteries and peritoneum.
  57. Superior mesenteric artery supplies the entire small intestine as well as the cecum (ileocolic), ascending colon (ileocolic), and transverse colon (middle colic)
  58. The inferior mesenteric artery supplies the descending colon (left colic), the sigmoid colon (sigmoid), and the rectum (superior rectal)
  59. The transverse colon, sigmoid colon, and cecum are intraperitoneal, but ascending, descending, are retroperitoneal (secondarily)
  60. Describe the blood supply of the small intestine, note the distinct features of jejunal and ileal vessel arcades and vasa recta.
  61. See above.
  62. The jejunum has longer vasa recta but a smaller number of arcades than the ileum
  63. Large Intestine:
  64. Identify the various parts including the appendix, their location and relationships to other abdominal structures including mesenteries and peritoneum.
  65. Ascending and descending colon are retroperitoneal (secondarily)
  66. Cecum, transverse colon, and sigmoid colon are intraperitoneal
  67. The rectum is retroperitoneal
  68. Describe the blood supply of the large intestine.
  69. See above, 3b
  70. Identify the appendix and its relationships.
  71. Retrocecal (64%): posterior to the cecum
  72. Subcecal (<1%): just below the cecum
  73. Pelvic (32%):sticking into the pelvis
  74. Preileal (<1%):Anterior to the distal-most part of the ileum
  75. Postileal(<1%):Posterior to the distal-most part of the ileum
  76. Describe the teniae coli, omental appendices, haustra, semilunar folds.
  77. Teniae coli:
  78. Smooth muscle bands
  79. 3 layers which correspond to muscularis externa in GI
  80. Mesocolic, free, and omental
  81. Omental appendices
  82. little processes or sacs of peritoneum filled with adipose tissue and projecting from the serous coat of the large intestine, except the rectum; they are most evident on the transverse and sigmoid colon, being most numerous along the free tenia.
  83. Haustra
  84. Small pouches caused by sacculation, which give the colon its segmented appearance. The taenia coli runs the length of the large intestine. Because the taenia coli is shorter than the intestine, the colon becomes sacculated between the taenia, forming the haustra. In between adjacent haustra are semi-lunar folds, known as the plicae semilunares.
  85. Haustral contractions are slow segmenting movements that occur every 25 minutes. One haustrum distends as it fills, which stimulates muscles to contract, pushing the contents to the next haustrum.
  86. Semilunar folds
  87. See above
  88. Understand the location and relations of the colic flexures.
  89. Right colic flexure (hepatic) (hepatocolic ligament?)
  90. Left colic flexure (phrenicocolic ligament)

ACCESSORY ORGANS OF THE GASTROINTESTINAL TRACT