Abdominal wall and Peritoneum Flashcards
The abdomen can be divided into nine regions. What is the horizontal plane most superior called?
Subcostal Plane
The abdomen can be divided into nine regions. What is the horizontal plane most inferior called?
Transtubercular plane
The abdomen can be divided into nine regions. What are the vertical lines called?
Midclavicular
The abdomen can be divided into nine regions. Name the regions starting from the top right
Right hypochondriac, epigastric, left hypochondriac
Right lumbar, umbilical, left lumbar
Right inguinal/iliac, hypogastric/suprapubic, left inguinal/iliac
The abdomen can also be divided into 4 quadrants. What is the plane that runs horizontally?
Umbilical plane -> runs straight through belly button, umbilical cord
The abdomen can also be divided into 4 quadrants. what is the plane that runs vertically?
Median plane -> in the middle
The abdomen can also be divided into 4 quadrants. Name the quadrants from top right.
Right upper quadrant, left upper quadrant, right lower quadrant, left lower quadrant.
What is the most superficial muscle of the anterolateral wall?
External oblique
What direction do the external oblique muscle fibers run?
Downwards and forwards
What is the origin of the external oblique muscle?
External surface of lower 8 ribs
What is the insertion of the external oblique muscle?
Linear alba, pubic tubercle, anterior half of the iliac crest
The free lower border of the external oblique muscle forms what ligament?
inguinal ligament
What is the intermediate muscle of the anterolateral abdominal wall?
Internal oblique
What direction do the fibres of the internal oblique muscles slope?
forwards and upwards
What is the origin of the internal oblique muscle?
Thoracodorsal fascia, anterior two-thirds of the iliac crest, lateral half of inguinal ligament
What is the insertion of the internal oblique muscle?
The inferior border of the lower 3 ribs, linea alba, and pubis via conjoint tendon
What is the deepest anterolateral muscle of the abdominal wall?
Transversus abdominis
What direction to the fibres in the transversus abdominis run?
Horizontally
What is the origin of the transversus abdominis?
Internal surface of the lower 6 costal cartilages, thoracodorsal fascia, iliac crest, the lateral third of the inguinal ligament
What is the insertion of the transversus abdominis?
Linar alba, pubic crest, pubis via conjoint tendon
What structures leave the intercostal spaces and run anteriorly, superficial to this muscle?
Lower thoracic nerves
What structures compose the rectus sheath in the transverse section?
Parietal peritoneum,
Trasversalis fascia,
Transversus abdominis
Internal oblique
external oblique
linear alba
rectus abdomins
What forms the anterior wall of the rectus sheath superior to the arcuate line?
Aponeurosis of external oblique and anterior lamina of internal oblique
What forms the anterior wall of the rectus sheath inferior to the arcuate line?
Aponeuroses of external oblique, inner oblique and transversus abdominis
What is the arcuate line?
The line formed where the posterior wall of the sheath thins out (as the aponeuroses of the muscles pass anterior to the rectus abdominis)
What are the contents of the rectus sheath?
Rectus abdominis, pyramidalis, superior and inferior epigastric vessels, lymphatic vessels, ventral rami of nerves T7-T12
Where does the pyramidalis originate?
Pubic crest
Where does the pyramidalis insert?
linear alba
what is the function of the pyramidalis?
Tenses the linear alba
What is the function of the rectus abdominis?
Flexes the trunk, compresses abdominal viscera and stabilises the tilt of the pelvis
What do the tendinous intersections do?
They fuse with the anterior wall of the rectus sheath
Which vessel does the inferior epigastric arise from?
external iliac
The inferior epigastric artery anastomoses with another vessel, what is it?
superior epigastric artery
where does the superior epigastric artery arise from?
musculophrenic artery
where does the superior epigastric artery enter the sheath?
the superior aspect, posterior to the rectus abdominis
in what direction do the thoracic nerves run within the sheath?
horizontally from lateral to medial
What structures contribute to the posterior wall of the sheath at the superior region?
posterior lamina of internal oblique and aponeurosis of transversus abdominis
What structures contribute to the posterior wall of the sheath at the inferior region?
transversalis fascia
Which nerves supply the anterolateral abdominal wall?
T7-T11, T12 (subcostal), L1 (ilioinguinal and iliohyogastric)
Between which muscles do these nerves run?
Internal oblique and transversus abdominis
Where do the lateral cutaneous branches of the T7-T11, T12 (subcostal), L1 (ilioinguinal and iliohyogastric) nerves pass through the subcutaneous tissue to reach the skin?
At the level of the anterior axillary line
Through which structure do the anterior cutaneous branches pass before entering the subcutaneous tisse?
rectus sheath
Which dermatomes supply the epigastric region?
T5-T9
Which dermatomes supply the umbilical region?
T10-T11
Which dermatomes supply the hypogastric region?
T12-L1
What and where is the inguinal canal?
An oblique passage through the abdominal wall just above the medial end of the inguinal ligament
Where does the inguinal canal extend from and to?
The deep inguinal ring to the superficial inguinal ring
Which structures form the boundaries of the inguinal canal?
Anterior wall -> external oblique aponeurosis
Posterior wall -> transversalis fascia and conjoint tendon
Floor -> inguinal ligament
Roof -> arching fibres of internal oblique and transversus abdominis
What does the inguinal canal contain?
spermatic cord (or round ligament in females), blood and lymphatic vessels, ilioinguinal nerve
What name is given to the layer of peritoneum that lines the abdominopelvic cavity?
Parietal peritoneum
What name is given to the layer of peritoneum layer that invests the viscera?
Visceral peritoneum
What is an omentum?
Double layer of peritoneum that extends from one organ to another?
What is the transverse mesocolon?
a broad, meso-fold of peritoneum, which connects the transverse colon to the posterior wall of the abdomen.
what is the lesser omentum?
the double layer of peritoneum that extends from the liver to the lesser curvature of the stomach (hepatogastric ligament) and the first part of the duodenum (hepatoduodenal ligament).
what is the greater omentum?
fibro-fatty tissue that extends from the greater curvature of the stomach to the transverse colon. It spans the width of the abdomen laterally and reaches the pelvis inferiorly.
what is the definition of a mesentery?
A double layer of peritoneum that suspends an organ from the body wall
What are 2 more examples of a mesentery?
sigmoid mesocolon and mesoappendix
what is the mesentary in the diagram?
The mesentery is an organ that attaches the intestines to the posterior abdominal wall in humans and is formed by the double fold of peritoneum.
How is the parietal peritoneum innervated?
somatic innervation
How is the visceral peritoneum innervated?
visceral (autonomic) innervation
What does the two types of innervation mean when considering pain perception?
The parietal peritoneum is sensitive to pressure, pain, temperature and laceration -> pain is well localised.
The visceral peritoneum is insensitive to touch, temperature and laceration, it is stimulated by stretch and chemical irritation - pain is poorly localised
Where does the greater omentum attach superiorly?
greater curvature of stomach and proximal duodenum
Where does the greater omentum attach inferiorly?
the anterior surface of the transverse colon
what is a thing to note about the greater omentum?
the length of the greater omentum is greater than the distance between the stomach and transverse colon so it doubles back on itself forming four layers that tend to be fused together. It may contain varying amounts of fat and is often referred to as the “fatty apron
Where does the lesser omentum attach superiorly?
Liver
