Abdomen Flashcards
What are the left and right crus of the diaphragm?
A muscular extension on each side of the vertebral column that firmly anchors the diaphragm to the anterolateral surface of the vertebral column as far down as L3 on the right and L2 on the left.
What are the medial and lateral arcuate ligaments?
Because the diaphragm is not complete posteriorly, the diaphragm is anchored to ligaments. The medial and lateral arcuate ligaments cross muscles of the posterior abdominal wall and attach to vertebrae, the transverse process of L1 and rib 12, respectively.
Where is the median arcuate ligament located?
It crosses the aorta and is continuous with the crus of the diaphragm on each side
Which nerves supply cutaneous innervation to the abdominal wall?
T6-L1
Which nerve root supplies the skin over the xiphoid process?
T6
Which nerve root supplies the skin around the umbilicus?
T10
Which nerve root supplies the skin in the suprapubic and inguinal regions?
L1
At what level does the celiac artery branch from the abdominal aorta?
upper border of L1
At what level does the superior mesenteric artery branch from the abdominal aorta?
lower border of L1
At what level does the inferior mesenteric artery branch from the abdominal aorta?
L3
Where does sympathetic innervation to abdominal viscera originate from?
Spinal cord levels T5 to L2
Where does parasympathetic innervation to abdominal viscera originate from?
Vagus nerve and spinal cord levels S2 to S4
What are the lines that delineate the the 9 regions of the abdomen?
Horizontal - subcostal (or transpyloric) and intertubercular
Vertical - two midclavicular lines
What are the 9 regions of the abdomen from right to left, superiorly to inferiorly?
Right hypochondrium, Epigastric region, Left hypochondrium
Right flank, Umbilical region, Left flank
Right groin (iliac fossa), Pubic region, Left groin
What are the two layers of superficial fascia in the anterior abdominal wall, below the umbilicus?
- Superficial fatty layer (Camper’s fascia) contains fat and varies in thickness
- Deeper membranous layer of fascia (Scarpa’s fascia) is thin and membranous, and contains little or no fat
What is Camper’s fascia continuous with in the scrotum?
Dartos fascia, a specialised layer containing smooth muscle fibres. In women, it retains some fat and is a component of the labia majora.
What are the five anterolateral muscles of the abdominal wall?
External oblique, internal oblique, transversus abdominis, rectus abdominis and pyramidalis muscles
Where is the lacunar ligament located?
Medial end of the inguinal ligament that passes backward to attach to the pecten pubis on the superior ramus of the pubic bone
Where is the transversalis fascia located?
Deep to the transversus abdominis muscle, it is a continuous layer that lines the abdominal cavity and continues in to the pelvic cavity
What is the origin of the external oblique muscle?
Muscular slips from the outer surfaces of the lower 8 ribs (ribs 5-12)
What is the insertion of the external oblique muscle?
Lateral lip of iliac crest and the aponeurosis ending in the linea alba
What is the function of the external oblique muscle?
Compress abdominal contents, flex the trunk, each muscle bends trunk to the same side, turning the anterior part of the abdomen to the opposite side
What is the origin of the internal oblique muscle?
Thoracolumbar fascia, iliac crest, lateral two-thirds of the inguinal ligament
What is the insertion of the internal oblique muscle?
Inferior border of the lower 3/4 ribs, aponeurosis endind in the linea alba, pubic crest and pectineal line
What is the origin of the rectus abdominis muscle?
Pubic crest, pubic tubercle and pubic symphysis
What is the insertion of the rectus abdominis muscle?
Costal cartilages of ribs 5-7 and the xiphoid process
What is the function of the rectus abdominis muscle?
Compress abdominal contents, flex vertebral column and tense abdominal wall
What is the origin of the transversus abdominis muscle?
Thoracolumbar fascia, iliac crest, lateral one-third of inguinal ligament, costal cartilages of lower 6 ribs
What is the insertion of the transversus abdominis muscle?
Aponeurosis ending in the linea alba, pubic crest and pectineal line
What is the function of transversus abdominis?
Compress the abdominal contents
What is the origin of the pyramidalis muscle?
Front of pubis and pubic symphysis
What is the insertion of the pyramidalis muscle?
Into the linea alba
What is the function of the pyramidalis muscle?
Tenses the linea alba
What is the innervation of the three flat abdominal muscles?
Anterior rami of lower six thoracic spinal nerves (T7-T12), Internal oblique and transversus abdominis also innervated by L1
What is the innervation of rectus abdominis?
Anterior rami of lower six thoracic spinal nerves (T7-T12)
What is the innervation of the pyramidalis muscle?
Anterior ramus of T12
Above the arcuate line, what does the anterior wall of the rectus sheath consist of?
The aponeurosis of external oblique
Half of the aponeurosis of internal oblique
Above the arcuate line, what does the posterior wall of the rectus sheath consist of?
(Other) Half of the aponeurosis of internal oblique
The aponeurosis of transversus abdominis
Below the arcuate line, what is the arrangement of the rectus sheath?
All of the aponeuroses are anterior to the rectus abdominis muscle, meaning the rectus abdominis is in direct contact with transversalis fascia posteriorly (at it’s inferior 1/3rd)
Describe the extraperitoneal fascia
It is deep to the transversalis fascia and superficial to the peritoneum. It contains varying amounts of fat, is continuous with a similar layer in the pelvic cavity and is abundant on the posterior wall, especially around the kidneys. It also continues over organs covered by peritoneal reflections,
The peritoneal cavity is closed in men but not in women, what are the two openings in women?
The uterine tubes provide a passage to the outside
What are the specific nerves which supply cutaneous innervation to the abdominal wall?
Intercostal nerves (T7-T11) - their lateral and anterior cutaneous branches Subcostal nerve (T12) Iliohypogastric and Ilioinguinal nerves (branches of L1, originate from the lumbar plexus)
Briefly describe the course of the anterior cutaneous branches of the lower intercostal nerves
Anterior cutaneous branch is given off as the intercostal nerve travels between the internal oblique muscle and the transversus abdominis muscle towards the rectus sheath. It enters the rectus sheath, passes posteriorly to the rectus abdominis muscle and near the midline the anterior cutaneous branch is given off. This branch passes through the rectus abdominis muscle and rectus sheath to supply the skin.
What is the superficial blood supply of the anterolateral abdominal wall?
Superiorly - Musculophrenic artery (a terminal branch of the internal thoracic)
Inferiorly - medially; the superficial epigastric artery
- laterally; the superficial circumflex iliac artery
(Both branches which supply the inferior superficial abdominal wall are branches of the femoral artery)
What is the deep blood supply to the anterolateral abdominal wall?
Superiorly - Superior epigastric artery (a terminal branch of the internal thoracic artery)
Laterally - Branches of the 10th and 11th intercostal arteries and the subcostal artery
Inferiorly - the medially place inferior epigastric artery and the laterally placed deep circumflex iliac artery. Both branches of the external iliac artery.
Very briefly describe the course of the inferior and superior epigastric arteries?
They both enter the rectus sheath, are posterior to the rectus abdominis muscle and anastamose with eachother
What are the tendinous intersections of the rectus abdominis muscle?
They are between the muscle bellies and it is where the muscle is attached to the rectus sheath.
How is the peritoneal cavity subdivided?
The greater sac and the lesser sac
What is the communication between the greater and lesser sac?
The omental (epiploic foramen), which is surrounded by numerous structures. Anteriorly, the portal vein, hepatic artery proper and bile duct. The IVC posteriorly and the caudate lobe of the liver superiorly. The first part of the duodenum inferiorly.
What is the arterial supply to the abdominal oesophagus?
Oesophageal branches from the left gastric artery (a branch of the coeliac trunk)
Oesophageal branches from the left inferior phrenic artery (from the abdominal aorta)
What are the four regions of the stomach?
Cardia - surrounding the opening of the oesophagus into the stomach
Fundus - area above the level of the cardial orifice
Body - largest region
Pyloric part - divided in to the pyloric antrum and the pyloric canal and is the distal end of the stomach
What is the greater curvature of the stomach an attachment for?
The gastrosplenic ligament and the greater omentum
What is the lesser curvature of the stomach an attachment for?
The lesser omentum
Where is the cardial notch?
The superior angle created where the oesophagus enters enters the stomach
What is the angular incisure?
The bend on the lesser curvature of the stomach
What is the arterial supply to the stomach?
Left gastric artery from the celiac trunk
Right gastric artery from the hepatic artery proper
Right gastroepiploic artery from the gastroduodenal artery
Left gastroepiploic from the splenic artery
Posterior gastric artery from the splenic artery (not always present)
What does the superior part (first part) of the duodenum pass anteriorly to?
It extends from the pyloric orifice of the stomach to the neck of the gallbladder. It passes infront of the bile duct, gastroduodenal artery, portal vein and inferior vena cava
Where are duodenal ulcers most likely to occur?
The first part of the duodenum, due to its close proximity to the acidic contents of the stomach before it is neutralised by bile
What structures are associated with the descending part (second part) of the duodenum?
Crossed anteriorly by the transverse colon, posterior to it is the right kidney and medial to it is the head of the pancreas.
It also contains the major and minor duodenal papilla
What are the major and minor duodenal papilla?
The major duodenal papilla is the common entrance of bile and pancreatic ducts
The minor duodenal papilla is the entrance for the accessory pancreatic duct
What structures are associated with the inferior part (3rd part) of the duodenum?
It is the longest part. It crossed the IVC, the aorta, and the vertebral column. It is crossed anteriorly by the superior mesenteric artery and vein
What structures are associated with the ascending part (4th part) of the duodenum?
It passes upward on, or to the left of, the aorta to approximately the upper border of L2 and terminates at the duodenojejunal flexure.
What is the duodenojejunal flexure surrounded by?
A fold of peritoneum containing muscle fibres called the suspensory muscle (ligament) of duodenum
What is the arterial supply to the duodenum?
Branches from the gastroduodenal artery
Supraduodenal artery (a branch of the gastroduodenal artery)
Duodenal branches from the anterior superior, anterior inferior, posterior superior and posterior inferior pancreaticoduodenal arteries
The first jejunal branch of the SMA
Where do the pancreaticoduodenal arteries arise from?
Anterior superior and Posterior superior arise from the gastroduodenal artery
Anterior inferior and Posterior inferior arise from the inferior pancreaticoduodenal artery which is a branch of the SMA
What are the characteristic features of the jejunum?
Mostly in the left upper quadrant, is larger in diameter and has a thicker wall than the ileum.
Numerous plicae circulares
Less prominent arterial arcades and longer vasa recta compared to those of the ileum
What is the blood supply to the jejunum?
Jejunal arteries from the SMA
What are the characteristic features of the ileum?
Mostly in the right lower quadrant. Compared to the jejunum, it has thinner walls, fewer and less prominent plicae circularis, shorter vasa recta, more mesenteric fat, and more arterial arcades.
What lies at the junction between the ileum and caecum?
Two flaps protude in to the lumen of the large intestine, the ileocecal fold, surrounding the opening. Musculature from the ileum continues in to each flap forming a sphincter.
What are the possible functions of the ileocecal fold?
Preventing reflux from the cecum to the ileum and regulating passage of contents from the ileum to the cecum.
What is the arterial supply to the ileum?
Ileal arteries from the SMA
An ileal branch from the ileocolic artery (from the SMA)
What are the four general features of the large intestine?
Large internal diameter compared to that of the small intestine
Peritoneal accumulations of fat - appendices epiploicae
Longitudinal muscles in its wall in three narrow bands - taeniae coli
The haustra of the colon (sacculations)