Give the 4 functions of the abdominal wall
• Firm flexible wall keeps abdominal viscera in abdominal cavity
• Protects abdominal viscera
• Maintains position of abdominal viscera against gravity
• Involved in actions that increase intra-abdominal pressure e.g. coughing or vomiting.
Name the flat muscles of the abdominal wall. State the direction in which they run.
1) External oblique – most superficial. Fibres run inferomedially (hands in pockets) and form an aponeurosis in the midline. In the mid line, the aponeuroses of all the flat muscles become entwined, forming the linea alba.
2) Internal oblique – Fibres run superiormedially (at a 90 degree angle to externalis). Contributes to linea alba
3) Transversus abdominis – Deepest layer of flat muscles. Transversely running fibres. Underneath this muscle is the transversalis fascia.
What is the function of the flat muscles of the abdominal wall?
Laterally flex and rotate trunk
State the vertical muscle of the abdominal wall. What is its function? What is its structure?
Split into two by linea alba.
Separated by tendinous intersections.
Assists flat muscles in compressing abdominal viscera, stabilises pelvis during walking, flexion of trunk, and depresses ribs.
Label the following
What is the rectus sheath? What forms its anterior and posterior walls?
• Formed by the aponeuroses of the three flat muscles and encloses the rectus abdominis
• Anterior wall formed by aponeuroses of the external and internal oblique
• Posterior wall formed by aponeuroses of the internal oblique and transversalis abdominis.
Where is the arcuate line? What occurs below it?
• The area below the arcuate line (midway between umbilicus and pub symphysis) There is not posterior wall to the sheath and the rectus abdominis is in direct contact with the transversalis fascia.
Label the following
Label the following
What is a grid iron incision?
cuts are made according to the way which the muscle fibres run to avoid cutting them.
Where is mcburney's point?
1/3 of the distance between the ASIS and the umbilicus
Where is a transverse incision made? What does it give access to?
Made inferior and laterally to the umbilicus. Gives access to colon, duodenum and pancreas
What is ectopia cordis and why does it occur?
Heart located out of thorax and is located in abdomen, cervical or thoracic area.
Occurs during lateral plate folding, sternum split and allows heart to leave thoracic cavity.
What is patent urachus? Why is it clinically relevant?
Urachus which connects bladder to umbilicus remains open. Can lead to adenocarcinoma of the urachus
What is patent vitellointestinal duct?
Duct connecting umbilicus and intestine remains open
What is exampholos? Why does it occur
Peritoneum pouch protrudes through the umbilicus, Occurs due to defect in the abdominal muscles formed.
Define referred pain.
Pain perceived at a site distant from the site causing the pain.
What is somatic referred pain?
Pain caused by a stimulus in the proximal part of a somatic nerve is perceived in the distal dermatome of the nerve.
Why does visceral referred pain occur? What makes visceral referred pain occur?
• Caused by ischaemia, inflammation or stretching
• Due to Low density of sensory innervation of viscera, pain is non specific. Convergence of the visceral nerves entering the spinal cord at the same level as somatic nerves results in the sensations being referred to surface areas of the body.
Explain why early appendicitis and late appendicitis manifest differently in terms of pain localisation
Early appendicitis is general midgut.
Later is right midgut
In early appendicitis - visceral referred pain
In late appendicitis - Appendix becomes so inflamed that it starts to irritate the posterior abdominal wall, localising the pain to that area.
Why does irritation of the diaphragm result in pain in the shoulder? Give 2 examples of what can irritate the diaphragm.
The phrenic nerve innervates the diaphragm, and therefore irritating the diaphragm can result in referred pain to the shoulder which is served by the spinal nerves C3-C5.
Ectopic pregnancy, and ruptured spleens.
Name the 3 parts of the small intestine and state them in proximal to distal order. Are they retro or intraperitoneal?
Duodenum, jejunum, ileum Proximal duodenum is retro.
Everything else in intra.
Label the following
Where is the pancreas located? Where is the duodenum in relation to the pancreas? Is it intra or retroperitoneal?
Posterior and inferior to the stomach.
Head of the duodenum curves around pancreas.
Aside from tail it is retroperitoneal
Where is the gall bladder located? is it intra or retroperitoneal?
Inferior to liver.
Where is the spleen located? intra or retro?
Posterior to the stomach
What spinal levels are the kidneys found at?
T11-L2 (left kidney) and T12-L3 (right kidney)
What is the peritoneal cavity and why is it considered a potential space?
Peritoneal cavity is a potential space between the parietal and visceral peritoneum. referred to as a potential space because excess fluid can accumulate in the peritoneal cavity resulting in ascites.
What can the greater sac be divided into? What does each division contain?
• Divided in two by the transverse colon into the supracolic and infracolic compartments.
• Supracolic lies above the transverse colon and contains the stomach, liver and spleen
• Infracolic lies below the transverse colon and contains the small intestine, ascending and descending colon
What is the difference between males and females in the peritoneum? Why is there a difference? Why is it clinically relevant?
• The rectovesical pouch is a double folding of peritoneum between the rectum and the bladder.
• Peritoneal cavity is completely closed in males.
• Rectouterine pouch between rectum and uterus. Vesicouterine pouch between bladder and uterus.
• The peritoneal cavity is not closed in females, and therefore infections of vagina and uterus may result in infection of peritoneum.
Define mesentery. What is contained within mesentery?
o Double layer of visceral peritoneum that connects an intraperitoneal organ to the posterior abdominal wall.
o Provides a pathway for nerves, blood vessels, and lymphatics from the body wall to the viscera
What is the function of the greater omentum?
Can migrate to infected viscera, has role in immunity
What is the mesocolon
mesentery of the colon
Where are the subphrenic spaces located?
Between the diaphragm and upper side of the liver. Located on each side of the falciform ligament which splits the liver in two.
What are the left and right paracolic gutters? Why are they clinically relevant?
Paracolic gutters are the spaces between the colon and the abdominal wall
Fluids can run up these gutters and infect or irritate areas remote from organ of origin.
Define a hernia
Where an internal part of the body pushes through a weakness in the muscle or surrounding tissue wall.
Give 4 areas a hernia can occur
Umbilical, inguinal, femoral, and epigastric
What are the two types of inguinal hernia? Define both of them. Why is it more common in males?
Direct and indirect
Direct - Goes through hesselbach's triangle, a weak area in the abdominal wall
Indirect - Abdominal contents protrude through the deep inguinal ring More common in males as they have a larger opening in the inguinal ring formed by the route of the descending testes.
Where does a femoral hernia occur? What does this area contain?
Femoral canal - lymph vessels
What is the roof of the inguinal canal made of?
What is the anterior wall of the inguinal canal made up of?
What is the floor of the inguinal canal made up of?
What is the posterior wall made up of?