Anterior abdominal wall Flashcards
what are the three layers of the thoracic wall and the way in which they travel
- External – anterior inferior
- Internal – anterior superior
- Innermost – going same was as internal intercostal
what is the three lateral layers of the abdominal wall and they way in which they travel
- external oblique - anterior inferior
- internal oblique - anterior superior
- tranversus abdominis - transverse (horiztonal)
what is the anterior wall in the abdomen
rectus abdominis
where does the external oblique and internal oblique and the transversus abdominis end
- they all end at the midclavicular line where an aponeurosis begins
what is the aponeurosis
- Aponeurosis is a tendon – it is a thin white flattened sheet of tendon
how does the Aponeurosis attach to each other (there is one on each side)
attaches to the other aponeurosis on the other side at the midline which is called the linea alba
describe the external oblique muscle
- the most superficial layer
- its fibres run in an anterior inferior direction
- Attach to the ribs superior and inferiorly attach to the iliac crest
- Muscle fibres end at mid clavicular line where the aponeurosis begins
- Aponeurosis attaches to the anterior superior iliac spine and the pubic tubercle this creates the inguinal ligament
describe the internal oblique muscle
- Middle layer
- Its fibres run in an anterior superior direction
- Attach to the ribs superiorly and the iliac crest inferiorly
- The sheet of muscle ends at the midclavicular line and then becomes aponeurosis
describe the transverses abdominis
- the deepest layer
- its fibres run in a transverse direction
- This means they pass horizontally across the abdomen
- Ends at the midclavicular line and then becomes an aponeurosis sheet
describe the rectus abdominis
- Extends from the costal margin (xiphoid process) superiorly to the pubic symphysis inferiorly
- The muscle is broken up into lots of different parts
- In between the muscle fibres there are tendon intersections
- In the midline there is the linea alba
what is the linea alba
fibrous structure that run down the midline that is where the apenrosis from the lateral abdominal muscles such as the external oblique attach
what is the rectus sheath
- this is how the rectus abdominis is covered with the Aponeurotic sheet that is derived from the aponeuroses of external oblique, internal oblique and transversus abdominis
what is the arcuate line
– this is below the arcuate line the structure of the rectus sheath changes and all run the aponeurosis run anterior to the rectus abdominis
describe the rectus sheath
- External oblique and half of internal oblique run anterior aperunosis to rectus abdominis
- Transversus abdominis and half of internal oblique run posterior apernuersis to rectus abdominis
what are the arteries in the thorax
- Thoracic aorta – gives on posterior intercostal artery
- Internal thoracic artery – gives of anterior intercostal artery
what artery goes from the thorax into the abdomen
internal thoracic artery
what does the internal thoracic artery run
- Internal thoracic artery run anterior to the diaphragm and then enter the abdomen
what happens when the internal thoracic artery enters the abdomen
this is where they change their name to the superior epigastric artery
what does the superior epigastric artery supply
rectus abdominis
what is the inferior epigastric artery a branch from
- There is also the inferior epigastric artery this is a branch from the external iliac artery
what does the inferior epigastric artery supply
these also supply the rectus abdominal – runs along the posterior aspect of the rectus abdominis and superiorly
what do the lower intercostal and lumbar arteries supply
- Lower intercostal and lumbar arteries supply blood to the lateral abdominal wall
where is the pubic tubercle
either side of the pubic symphysis
What does the external oblique attach to
- External oblique attaches to the anterior superior iliac spine and the pubic tubercle which is either side of the pubic symphysis
what is the inguinal ligament
- Inferior border of external oblique is called the inguinal ligament
what passes under the inguinal ligament
- The femoral artery, femoral nerve and femoral vein passes underneath it
how is the inguinal canal created
- The inferior border of the external oblique aponeurosis rolls under itself to create the inguinal ligament, this curling creates the inguinal canal
what passes through the inguinal canal
- Inguinal canal is in the roll itself, passes through the inguinal canal is the spermatic cord (testicular artery and vein and the vas deferens) in males and in females it is the round ligament of the uterus (thin fibrous cord)
the inguinal canal is …
more developed in males than in females
where do the testes develop
- The testes develop on the posterior abdominal wall and descend through the inguinal canal to reach the scrotum
where do testes get there blood supply
- Testes get their blood supply from the abdomen aorta
- Tetricualr artery starts in the abdominal and descends throught the pelvis and then the abdominal wall to meet the scrutum
what is an inguinal hernia
- A hernia is a protrusion of the peritoneum and viscera such as small intestine through a opening or weakness
how much do inguinal hernias account for abdominal hernias
75%
what is the risk of hernias
- Hernias are usually harmless but they have a risk of having their blood supply cut off
- If the blood supply is cut of in the abdominal wall it becomes a medicial and surgical emergency
who do hernias occur in
- Only really in men, in women inguinal canal is not that big therefore they don’t tend to get affected,
what are the two main types of hernia
direct and indirect
describe the direct hernia
- occur in middle aged men
- where the abdominal muscles have got weaker or they have put on weight,
- therefore it is acquired
- rarely enters the scrotum
describe the indirect hernia
– congenital
- they are linked to the development of the testes,
- these commonly enter the scrotum when the abdominal contents are pulled down with the teste
what is a femoral hernia
- This is when any abdomen content goes underneath the inguinal ligament
describe the 9 abdomen region
- Two midclavicular lines
- Subcostal plane
- Transtubercular plane this goes through the iliac tubuercles
- Right hypochondrium, epigastric, left hypocondrium
- Right lumbar, umbilical, left lumbar
- Right iliac, pubic, left iliac
what are the three parts of the oesophagus
foregut
midgut
hindgut
describe the parts of the foregut and its blood supply
- Oesophagus, stomach, 1st part duodenum, liver, pancreas, spleen
- Coeliac trunk supplies blood supply
describe the midgut and its blood supply
- Caudal (2nd part)duodenum, small and large intestine up to splenic flexure
- Superior mesenteric artery blood supply
describe the handout and its blood supply
- Splenic flexure, descending, sigmoid colon, rectum, upper anal canal
- Inferior mesenteric artery blood supply
- 2/3 along transverse colon is when it becomes hindgut
when does the nerve supply change in the gut
the midgut and hindgut
describe the oesophagus
- Muscular tube
- Connects from the pharynx superiorly to the stomach inferiorly
- 25cm in length
describe the muscles of the oesophagus
- Internal circular muscle fibres
- External longitudinal fibres
- Upper 1/3 is skeletal muscle – swallowing starts as a voluntary process therefore its skeletal and then it becomes involuntary so it changes to smooth muscle
- Lower 1/3 smooth muscle
what is the upper oesophageal sphincter
an anatomical sphincter
describe the upper oesophageal sphincter
- Anatomical sphincter produced by skeletal muscle the cricopharyngenus
- Also the inferior pharyngeal sphincter
what is the lower oesophageal sphincter
an physiological sphincter
what forms the lower oesophageal sphincter
Aided anatomically by
- The oesophagus enters the stomach at an acute angle – prevents food leaving the stomach and makes it move in one direction only
- The right crus of the diaphragm has a pinch cock effect aids food moving in one direction only, diaphragm essentially acts as an sphincter
what are the three constrictions in the oesophagus
- Cervical constructions – upper oesophageal sphincter
- Thoracic constrictions – within the throax at the point where the left main bronchus and arch of aorta passing over the oesophagus
- Diaphragmatic constriction – when it passes through the diaphragm
what is the nerve supply to the oesophagus
- Vagus nerve – supplies the oesophagus
where does the oesophagus enter the stomach
Enters the stomach at the cardinal orifice (7th costal cartilage left midline)
describe the structure for the stomach
- Made out of the fundus at the top, body, antrum, pylorus (there is a sphincter here called the pylorus sphincter)
- Either side of the stomach there is the lesser curvature and the greater curvature
what are the internal folds in the stomach called
rugae
what is the boundary between the oesophagus and the gastric mucosal
zig zag line
describe the structure of the duodenum
- Fixed part
- Retroperitoneal
- C shaped loop of the small intestine
- Curves around the head of the pancreas
- Split into 4 parts
- Part 1 superior
- Part 2 descending
- Part 3 horizontal
- Part 4 ascending
what is important about part 2 descending part of the duodenum
this is where the bile duct and pancreatic duct drain into the descending part of the duodenum, this is where the foregut ends
where is the jejunum found
- This is found in the largely in the left upper quadrant
there is not a point at which
the jejunum becomes the ileum
where is the ileum found
- The ileum is found largely in the right lower quadrant
describe the structure of the jejunum
- Jejnum is a major point of food absorption therefore there is loads of folds of mucosa,
- It has Plicae circulars
- And it has a Greater vascularity than the ileum
- Longer vasa recta
describe the structure of the ileum
- Shorter vasa recta
- Less vascuarlity
- Less plicae ciarularis
- Peyer’s patches
describe the structure of the large intestine
- More fixed in place
- Ascending and descending are fixed in place and cannot move
- The bubbles are called haustra and the internal folds that create them are called semi lunar folds
- The longitudinal muscle is collected into three bands these are called the tenia coli
- Fatty tags that go along the tenia coli are called omental appendices
what makes up the large intestine
- Start with the cecum – appendix projects of it
- Asecndng colon
- Hepatic flexcure
- Transvere
- Splexic flexus
- Descending colon
- Sigmoid
- Rectum
- Anal canal
what is the most common place where the appendix is attached to the cecum
retrocaecal
