Session 3 - Abdominal wall and the mesenteries Flashcards
What are the three borders of the abdominal wall?
- Anterior
- Lateral (Together with anterior sometimes known as anterolateral)
- Posterior
What is the anterolateral abdominal wall bound by superiorly and inferiorly?
- Superiorly by the cartilages of the 7th-10th ribs and xiphoid process of the sternum
- Inferiorly by the inguinal ligament and the superior margins of the anterolateral aspects of the pelvic girdle
What does the anterolateral abdominal wall consist of (in order)
- Skin
- Subcutaneous tissue
- Muscle and their aponeurosis
- Deep fascia
- Extraperitoneal fate
- Parietal peritoneum
Where are the bony attachment points of the ribs?
- Ribs
- Spine
- Illiac crest
What is needed in the midline of the abdomen for muscles to contract against?
• Linae albase
What are the three layers of muscles of the abdominal wall?
- External obliques (Attached to ribs)
- Internal obliques (attached to illiac crest)
- Transversalis abdominus (Attached to lumbar verterbra)
What exists below the three layers of muscle?
• The transveralis fascia
What is the purpose of the greater omentum?
• Walls off areas of infection
What is the arcuate line?
• The point at which the posterior rectus abdominal sheath stops at a point 1/3rd from the umbilicus to the symphysis pubis
What is divarication of recti?
• Due to laxity of linea alba
Why does bleeding occur in rectus abdominus muscle?
• Due to warfarin use and in which haemorrhage
What is Cullen’s sign?
• Sign of pancreatitis
Haemorrhage into rectus abdominu
What is the umbilicus?
Embryological remenant found at spinal level L3
What is the epigastric fossa?
- Slight depression in the epigastric region, just inferior to the xiphoid process
- Noticeable when a person is in the supine position because the abdominal organs spread out
What is commonly felt at epigastric fossa?
• Heartburn
What is the linea alba?
• Aponeuroses of abdominal muscles, separating the left and right rectus abdominis
What happens if one has a lax linea alba?
• Muscles spread apart
Called divarication of recti
What is the pubic crest and symphisis?
• Upper margins of the pubic bones and the cartilaginous joints that unite them. Can be felt at the inferior end of the linea alba.
What is the inguinal groove?
• Skin crease that is parallel and just inferior to the inguinal ligament (runs between ASIS and pubic tubercle). Marks the division between the abdominal wall and the thigh.
What are the semilunar lines?
• Slight curves tendinous lines on either side of the rectus abdominis
What are the tendinous intersections of rectus abdominis?
• Tendinous lines running horizontally across rectus abdominis
What is the arcuate line?
• Where the fibrous sheath of the rectus abdominous stops 1/3 of the way from the umbilicus to the pubic crest
What is McBurney’s point?
- 2/3rds of the distance between the umbillicus and anterior superior illiac spine
- Appendicectomy
- Use a gridiron incision
How many muscles are present in the abdominal wall?
• 5
Name the three flat muscles of the abdominal wall
- External oblique
- Internal oblique
- Transversus abdominis
Name the two vertical muscles of the abdominal wall
• Rectus abdominis and pyramidalis
In what direction do the oblique flat muscle run?
• Diagonally and perpendicular to each other
In which direction do the fibres of transversus abdominus run?
• Transversely
What is the origin of external oblique
• External surfaces of the 5th to 12th ribs
What is the insertion of external oblique
- Linea alba
- Pubic tubercle
- Anterior half of iliac crest
What is the origin of the internal oblique?
- Thoracolumbar fascia
- Anterior two thirds of iliac crest
- Connective tissue deep to lateral third of inguinal ligament
What is the insertion of the internal oblique?
- Inferior borders of the 10th to 12th ribs
- Linea alba
- Pectin pubis
What is the origin of the transversus abdominis?
- Internal surfaces of 7th to 12th costal cartilages
- Thoracolumbar fascia
- Iliac crest
What is the insertion of the transversus abdominis?
• Linea alba with aponeuroses of internal oblique
What is the rectus sheath?
- Tendinous sheath which encloses the rectus abdominus (vertical muscle, forms the abs!)
- Formed from the strong, sheet like aponeuroses of the three flat musclees
Where does the linea alba extend to and from?
• Xiphoid process to the pubic symphysis
What are the two muscles found in the rectus sheath?
• Rectus abdominis
Does the rectus sheath completely extend all the way to the pubic symphsis?
- Posterior rectus sheath disappears at arcuate line
* 1/3 way from ubilicus to pubic crest
What is the linea semilunaris?
• Curved tendinous line places on either side of the rectus abdominus
What are the tendinous horizontal lines breaking up the rectus abdominis called?
• Tendinous intersections
What occurs if muscle is used as a sutural locaiton?
• Eventual incisional hernia through weakness in wall
Name four different abdominal inscisions
- Midline incision
- Transverse incsision
- Appendicectomy
- Gridiron incision
What is a midline incision?
• Surgeons suture the linea alba together to provide strong closure
What is a transverse incision?
• surgeons suture the external oblique aponeuroses
Where is an appendicectomy incision placed?
- McBurney’s point
- 2/3rds of the distance between the umbilicus and ASIS
Through a gridiron muscle splitting incision
What is gridiron incision?
- Put scissors in and open and close them to separate out the muscle fibres, followed by the next two layers.
- This is in order to separate out the fibres of the external and internal obliques and the transversalis
