Abdomen Flashcards
Name the layers of the anterior abdominal wall.
Skin Superficial fascia (Camper's & Scarpa's) External oblique Internal oblique Transversus abdominus Transversalis fascia Extraperitoneal fat Peritoneum
Name the attachments of the external oblique muscle.
Origin: ribs 5-12
Insertion: linea alba, iliac crest & pubic tubercle
Name the attachments of the inguinal ligament.
Origin: ASIS
Insertion: pubic tubercle
What is the lacunar ligament?
A fibrous extension from the medial part of the inguinal ligament toward the pectineal line.
Name the attachments of the internal oblique muscle.
Origin: iliac crest & ASIS / inguinal ligament (lowermost fibres)
Insertion: ribs 10-12 / conjoint tendon
Name the attachments of transversus abdominus.
Origin: costal cartilages 7-12 & iliac crest / inguinal ligament (lowermost fibres)
Insertion: linea alba & pubic crest / conjoint tendon
What is the arcuate line?
The arcuate line demarcates the lower limit of the posterior layer of the rectus sheath.
Name the attachments of rectus abdominis.
Origin: pubic crest & pubic symphysis
Insertion: xiphoid process & costal cartilage of ribs 5-7
What is the rectus sheath?
The rectus sheath is the aponeurosis of the three flat-layer muscles that encloses rectus abdominus; it is deficient in the lower 1/4 of the abdomen.
Which artery supplies the anterior abdominal wall, superiorly and laterally?
The musculophrenic artery.
What does the musculophrenic artery supply?
The anterior abdominal wall, superiorly and laterally.
Which artery provides blood supply to rectus abdominis?
The superior epigastric artery.
Which arteries run within the rectus sheath posteriorly?
The superior & inferior epigastric arteries.
Which muscle does the superior epigastric artery supply?
Rectus abdominis.
Which artery provides blood supply to the inferior aspect of the anterior abdominal wall muscles laterally?
The deep circumflex iliac artery.
Which artery provides blood supply to the inferior aspect of the abdominal wall (superficial fascia, not muscular)?
The superficial epigastric artery.
Which spinal segments innervate the anterior abdominal wall?
T6-L1
What is the inguinal canal?
The inguinal canal is a passage through the anterior abdominal wall formed by the descent of the testes from the posterior abdominal wall to the scrotum.
What is the deep inguinal ring?
A hole in the transversalis fascia.
What is the superficial inguinal ring?
A fibrous split in the aponeurosis of the external oblique muscle.
Describe the path that the testes take through the inguinal canal.
The testes originally develop within the extraperitoneal fat. They create a hole in the transversalis fascia, go underneath the arch of the fibres of transversus abdominus & internal oblique and find a fibrous split within the aponeurosis of external oblique.
Name the boundaries of the inguinal canal.
RAFP / MALT
Roof: Muscles (IO & TA)
Anterior: Aponeurosis (EO & IO)
Floor: Ligaments (inguinal & lacunar)
Posterior: Tendon (conjoint tendon & transversalis fascia)
What is an inguinal hernia?
A protrusion/passage of abdominal contents into the inguinal canal.
What is the difference between an indirect & a direct inguinal hernia?
An INDIRECT inguinal hernia is a protrusion through the deep ring into the inguinal canal. Contents may traverse through the entire length and pass into the scrotum. They arise from incomplete closure of the processus vaginalis.
A DIRECT inguinal hernia is a protrusion into the inguinal canal through an area of weakness in its posterior wall. The contents do not traverse the length of the canal and rarely enter the scrotum. They often result from a weakened muscular wall of the abdomen.
What is the processus vaginalis?
When the testes descend into the scrotum, they drag a layer of peritoneal membrane with them, creating the processus vaginalis, a tube that connects the intra-abdominal cavity and the scrotum.
Name the attachments of psoas major.
Origin: transverse processes of T12-L4
Insertion: lesser trochanter of the femur
Name the attachments of quadratus lumborum.
Origin: iliac crest
Insertion: 12th rib & L1-L5
Name the attachments of iliacus.
Origin: iliac crest
Insertion: lesser trochanter of the femur
Name the compartments of the thoracolumbar fascia and their contents.
Anterior muscle compartment (formed by anterior & medial layers of thoracolumbar fascia): quadratus lumborum
Posterior muscle compartment (formed by medial & posterior layers of thoracolumbar fascia): erector spinae muscles
Where are the kidneys located in relation to the peritoneum?
Retroperitoneal - they sit against the posterior abdominal wall in a fixed position (T12-L3) outside the peritoneal cavity.
What covers the anterior & posterior surfaces of the kidneys?
Anterior: peritoneum
Posterior: quadratus lumborum
Name the structures at the renal hilum.
RAP (from front to back)
Renal vein
Renal artery
Renal pelvis
The right renal vein goes directly to the IVC. Why doesn’t the left renal vein? Describe its pathway.
The left renal vein’s path is obstructed by the aorta, so it passes in front of it (but behind the superior mesenteric artery).
Where is the lymph drained from the kidneys collected?
The paravertebral nodes.
What is the accessory renal artery, and how does it develop?
The accessory renal artery supplies additional arterial blood to the kidneys. Initially, the kidneys develop lower down in the pelvis, but they appear to move upwards as the abdominal wall grows due to their different growth rates. While in the pelvis, they receive blood supply at this level, but when they move up, they receive a new blood supply from the renal arteries. In some people, this original artery (the accessory renal artery) remains.
Describe the path of a ureter once it leaves the kidney, naming the structures it passes over.
The ureter runs in front of psoas major and over the tips of the transverse processes of the lumbar vertebrae.
Name the location of the three narrowing points of the ureters.
- Ureteropelvic junction (just below renal pelvis)
- Pelvic brim
- Terminal portion (at the bladder)
What is the clinical significance of narrowings in the ureter?
Kidney stones can get lodged there.
Describe the arterial supply of the ureters.
Abdominal: renal artery, gonadal artery, branches of abdominal aorta
Pelvic: branches of common iliac artery (superior & inferior vesical arteries)
Where are the ureters located in relation to the peritoneum?
Retroperitoneal.
What happens to the mucosa at the esophagogastric junction? Is it gradual or sudden?
There is a sudden change from oesophageal mucosa to gastric mucosa.
What is a hiatal hernia?
A hiatal hernia is when part of the stomach is pulled through the oesophageal hiatus.
What is the difference between a paraesophageal and sliding hiatal hernia?
A paraesophageal hernia is when the oesophagus pulls part of the top of the stomach into the thorax ALONGSIDE it.
A sliding hiatal hernia is when the oesophagus pulls the proximal part of the stomach directly into the thorax.
What is the cardiac notch?
The angle between the distal part of the oesophagus and the fundus of the stomach.
What is the difference between a functional and anatomical sphincter?
Functional sphincters achieve their action through muscle contraction around or within the structure.
Anatomical sphincters have a localised muscle thickening to facilitate their action as a sphincter.
What is the function of the pyloric sphincter?
It stops the contents of the stomach being dumped into the duodenum by slowing the process down.
What is the angular notch?
The angular notch is an anatomical landmark that represents where the body of the stomach ends and the pyloric part begins.
Where is the stomach located relative to the peritoneum?
Intraperitoneal.
What are the name of the mesenteries attached to the stomach, and what are their other attachments?
Lesser omentum: connects the lesser curvature (including the beginning of the abdominal oesophagus) to the visceral part of the liver
Greater omentum: connects greater curvature to the posterior abdominal wall
What is the mucosa of the stomach called?
Rugae.
Name the vessels that run along the lesser curvature.
The left & right gastric arteries.
Name the vessels that run along the greater curvature.
The left & right gastro-omental arteries.
Where is the duodenum located related to the peritoneum?
Retroperitoneal (except for the very beginning, which is intraperitoneal and has a mesentery). It sits against the posterior abdominal wall.
Describe the first part of the duodenum.
The first part of the duodenum, the ampulla, sits against the IVC and is very short.
Describe the second part of the duodenum.
The major duodenal papilla are located within the second part of the duodenum. These represent the common opening point for the main pancreatic duct and the common bile duct, and are thus where the majority of enzymes and bile are secreted.
Where are the majority of enzymes & bile secreted in the digestive tract?
At the major duodenal papilla in the second part of the duodenum.
Where are the major duodenal papilla located?
On the posterior and medial wall of the second part of the duodenum.
Describe the third part of the duodenum.
This is the longest part of the duodenum. It is located at L3 and crosses from the right to the left, in front of the IVC and abdominal aorta but behind the superior mesenteric artery and vein.
Which section of the duodenum is the longest?
The third section.
Describe the blood supply of the duodenum.
The first half of the duodenum is supplied by the gastroduodenal artery (a branch of the celiac trunk). The rest is supplied by the inferior pancreaticoduodenal arteries (branches of the superior mesenteric artery). These arteries meet & anastomose.
What is the DJ flexure?
The point where the small intestine transitions from the retroperitoneal duodenum to the intraperitoneal jejunum.
Where is the jejunum located in relation to the peritoneum?
Intraperitoneal.
What is the name of the landmark where the duodenum transitions into the jejunum?
The DJ flexure.