Abdomen Flashcards
Origin Insertion Action Nerve Special features External oblique
Anterior angle of lower 8 ribs. Upper four slips interdigitate with serratus anterior, lower 4 with latissimus dorsi.
Outer lip of iliac crest, inguinal ligament, pubic tubercle and crest, rectus sheath, linea alba and xiphisternum (as aponeurosis)
Support, expiration, raises intraabdominal pressure and abducts and rotates trunk
Anterior primary rami (T7-T12)
Runs down and forwards
Free posterior muscular border
Free upper aponeurotic border
Aponeurosis below line from ASIS to umbilicus
Forms 3 ligaments; pectineal, inguinal, lacunar
What is the only structure in the anterior rectus sheath above the costal margin?
Free horizontal upper border of external oblique aponeurosis
List the layers of the abdomen from superficial to deep above the arcuate line
Skin Subcutaneous fat Camper's fascia Scarper's fascia External oblique/anterior rectus sheath (medial) Internal oblique Transversus abdominus/ rectus abdominus (medial) Posterior rectus sheath Transversalis fascia Peritoneum
Origin Insertion Action Nerve Special features Internal oblique
Lumbar fascia, anterior 2/3/ of iliac crest and lateral 2/3 of inguinal ligament
Linea alba, rectus sheath conjoint tendon to pubic crest and pectineal line
Support, expiration, raises intraabdominal pressure and with muscles on opposite side abducts and rotates trunk
Anterior primary rami (T7-T12)
Conjoint tendon supplied by ilioinguinal nerve
Anterior configuration changes at arcuate line. A free lower border arches over the spermatic cord
Aponeurotic medial tip of 9th costal cartilage. Forms conjoint tendon. Forms floor of lumbar triangle. Upwards and inwards
What are the borders of the lumbar triangle?
Anterior-external oblique
Floor-internal oblique
Medial-latissimus dorsi
Inferior-iliac crest
Origin Insertion Action Nerve Special features Transversus abdominus
Costal margin (lower 6 ribs), lateral 1/3 of inguinal ligament, ant 2/3 of iliac crest, 12th rib
Aponeurosis of rectus sheath, conjoint tendon to pubic crest and pectineal line
Support, expiration, conjoint tendon supports inguinal canal
Ant primary rami (T7-T12) Conjoint tendon supplied by ilioinguinal nerve
Interdigitates with diaphragm. Lies horizontally.
Becomes conjoint tendon
Where is the arcuate line?
Halfway between pubic symphysis and umbilicus
Origin Insertion Action Nerve Special features Rectus abdominus
Pubic crest and pubic symphysis by two heads
5th, 6th, 7th costal cartilages
Flexes trunk, aids forced expiration and increases abdominal pressure
Ant primary rami
3 tendinous intersections, umbilicus, xiphisternum and in between
Where is the superficial inguinal ring?
Just above and lateral to pubic tubercle (a triangular gap in the external oblique aponeurosis)
Origin Insertion Action Nerve Special features Pyramidalis
Pubic crest anterior to rectus abdominus origin
Lower linea alba
Reinforces rectus sheath
Subcostal nerve (T12)
Where does the linea alba attach?
Xiphisterum and pubic symphysis
What forms the rectus sheath?
Internal oblique splits into anterior and posterior layers to enclose the rectus muscle
External oblique fuses with anterior layer (only medially)
Transversus fuses with posterior layer
Posterior layer has a free lower margin. Nil posterior rectus sheath below arcuate line.
What is the contents of the rectus sheath?
Intercostal nerves
Rectus muscle
Pyramidalis muscle
Superior epigastric artery (supplies rectus abdominus)
Inferior epigastric artery (anastomosis with superior within sheath)
What is the blood supply to the muscles of the anterior abdominal wall?
Intercostal
Epigastric
Deep circumflex iliac artery
How long is the inguinal canal?
Runs from superficial to deep ring
4cm
What are the boundaries of the inguinal canal?
Anterior external oblique aponeurosis
Lateral internal oblique
Roof, lower edges of internal oblique and transversus
Floor inguinal ligament
Posterior conjoint tendon medially and transversalis fascia throughout
Where is the deep inguinal ring?
1.25cm above the midpoint of the inguinal ligament and is an opening in the transversalis fascia
How does the inguinal nerve enter the inguinal canal?
Pierces the internal oblique muscle, not through deep ring
Supplies inguinal region skin, upper thigh anterior 1/3 of scrotum and root of the penis
What are the boundaries of Hesselbach’s triangle? What occurs there?
Lateral inferior epigastric vessels
Medially Rectus abdominus
Inferior inguinal ligament
DIRECT hernias
What passes through the deep ring?
Male: Vas deferens Artery to vas deferens Testicular artery Testicular veins Degenerated processus vaginalis Genital branch of genitofemoral nerve Autonomic nerves Lymphatics Female: Degenerated processus vaginalis Round ligament Lymphatics from uterus
What are the three layers of the spermatic cord?
Internal spermatic fascia (derived from transveralis fascia at deep ring)
Cremaster muscle and fascia (arises from inguinal ligament, internal oblique and transverse abdominis muscles)
External spermatic fascia (arises from external oblique aponeurosis)
What are the contents of the spermatic cord?
Vas deferens Artery to vas deferens Testicular artery Cremasteric artery Pampiniform plexus Lymphatics Genital branch of genitofemoral nerve Sympathetic twigs Processus vaginalis
Where is the epididymus in relation to the testis?
Attached to posterolateral service
There is an anastomosis of between testicular, cremasteric and ductal arteries
What is the name of the membrane that covers the testis?
Tunica albuginea
Tunica vaginalis
Why does varicocele occur more often on the left than the right?
Left testicular vein drains into left renal vein at a right angle
Right vein drains inferior vena cava at an acute angle
What is the lymph drainage from the testicles?
Para aortic nodes
What is the nerve supply to the testis?
Sympathetic nerves (mostly from T10)
Where is the vas deferens in relation to the epididymus?
The vas deferens is a continuation of the epididymus. Pierces the prostate and opens by the ejaculatory duct into the urethra.
Describe the course of the developing testis
Starts at gonadal ridge
Develops from yolk sac with mesonephros
Remaining mesonephros becomes paradidymis
Mesodermal cells called gubernaculum connect the lower pole of the testis to the abdominal wall( becomes the scrotum)
Processus vaginalis protrudes down inguinal canal into scrotum
7th month of fetal life testis is in the deep ring
What are the boundaries of the lesser sac?
Anterior: posterior wall lesser omentum, visceral peritoneum over posterior stomach and posterior layer of greater omentum, portal triad
Posterior: Pancreas, gastrosplenic/splenorenal ligaments anterior layer of greater omentum (which is attached to transverse colon)
Cavity doesn’t extend below greater omentum
How many layers in the greater omentum?
4
A double sheet of peritoneum folded in on itself
What are the attachments of the lesser omentum?
Attached along the stomach from right side of oesophagus and along first 2cm of duodenum
Right free margin (foramen of winslow).
Liver attachment is L-shaped to the fissure for ligamentum venosum and porta hepatis
Contains portal triad (common bile duct, portal vein and hepatic artery)
What are the boundaries of the epiploic foramen of winslow?
Upper boundary caudate process of liver
Lower boundary first part duodenum
Posterior inferior vena cava
Anterior portal triad in lesser omentum
Where does the fluid collect in the abdomen and why?
Pelvis
Hepatorenal pouch
Lowest parts of abdomen
Which of the following are intraperitoneal? Common iliac artery Inferior vena cava Ureters Testicular arteries Superior mesenteric vessels Root of mesentery
Inferior vena cava
Root of mesentery
Superior mesenteric vessels
What is the root of the mesentery and where does it begin?
Duodenojejunal junction. Crosses the 3rd part of duodenum where superior mesenteric vessels enter, crosses aorta, inferior vena cava, right psoas muscle and ureter. Attachment is 15cm.
What does the foregut become and which artery supplies these structures?
Liver
Pancreas
Supplied by coeliac artery (also supplies stomach and spleen)
Boundary is the bile duct entrance into duodenum
What defines the midgut?
The section of gut which physiologically herniates into the umbilical cord at 6 weeks
Supplied by the superior mesenteric artery
Becomes duodenum, ileum, caecum and transverse colon
What are the branches of coeliac trunk?
Left gastric artery: gives oesophageal branches and supplies stomach
Splenic artery: tortuous. Gives short gastric and left gastroepiploic artery. Supplies spleen and pancreas.
Common hepatic artery: gives right gastric and gastroduodenal artery (gives right gastroepiploic and superior pancreatoduodenal artery)
What is the venous drainage of foregut?
Portal vein
Passes through liver
Inferior vena cava
What is the origin of the SMA
From aorta 1cm below coeliac trunk
Level of L1 vertebra
Posterior to pancreas
What are the branches of the SMA
Inferior pancreaticoduodenal Middle colic artery Jejunal and ileal arteries Right colic artery Ileocolic artery (caecal and appendicular artery)
What is the venous drainage of the midgut?
Superior mesenteric vein
Where does the IMA arise from?
Level of L3 vertebrae
3-4cm above aortic bifurcation
Level of umbilicus
What are the branches of the IMA?
Left colic artery (crossed anteriorly by IMV)
Sigmoid arteries
Superior rectal arteries
What is the venous drainage of the hindgut?
Inferior mesenteric vein
Lies on left psoas muscle
Drains into superior mesenteric vein
What are the three groups of lymph nodes which supply the small and large intestine?
- Within the peritoneum-mural (SI) and paracolic (LI)
- Lymph vessels which lie with blood supply
- Preaortic lymph nodes
Where does the enteric nervous system lie?
Myenteric plexus- between 2 layers of the gut
Submucous plexus- in submucosa
What are the three layers of the alimentary tube?
Epithelium
Lamina propria
Muscularis mucosae
Describe the cell types found in oeseophagus
Stratified squamous non keritinising
Muscularis mucosae absent from top but thicker than any other part of alimentary tract
Mucus secreting glands in both upper and lower ends
Describe the cells found in the stomach
Single layer columnar epithelium
Parietal cells (intrinsic factor binds B12, pepsin and Hydrochloric acid)
G cells secrete gastrograffin
D cells secrete somatostatin
Describe the cells found in the small intestine
Villi
Mucus secreting goblet cells
Only duodenum has mucus secreting glands- first part (ampulla) has no circular folds
Only terminal ileum has peyers patches
Describe the cells found in the large intestine
No villi
Only glands with goblet cells
Anal canal goes back to stratified squamous
What does the stomach lie anterior to?
Pancreas Splenic artery Transverse colon Upper left kidney Spleen Aorta and coeliac trunk
What is the blood supply to the stomach?
Coeliac trunk Left gastric artery Right gastric artery Short gastric arteries Gastroepiploic vessels
What is the key difference between the anterior and posterior vagal trunks at the oesophagus?
Anterior vagal trunk is in contact with anterior oesophageal wall
Posterior vagal trunk is not in contact with oesophagus
What are the layers of the stomach?
Outer longitudinal
Middle circular
Inner oblique muscle layer
How do the parts of the duodenum relate to vertebral levels and the peritoneum?
1st part: L1 ant to bile duct, portal vein and gastroduodenal artery
2nd part: right side of L2, ant to right kidney, receives bile duct and pancreatic duct
3rd part: crosses in front of L3, ant to l+r psoas muscle, inferior vena cava and aorta
4th part: left of L2, ant to left psoas muscle
First 2.5 cm intraperitoneal
What is the blood supply to the duodenum?
Superior and inferior pancreatoduodenal arteries- but first 2cm receives blood hepatic, gastroduodenal, supraduodenal, right gastric and right gastroepiploic arteries
Key differences between jejunum and ileum
Jejunum feels thick- 2 walled, ileum feels thin
Ileum-peyers patches and meckels’ diverticulum 2% population, 2 inches long, 2 feet from caecum
Both supplied by SMA, forms arterial arcades, much more arcades in ileum
How do the teniae coli of the caecum relate to the appendix?
All 3 teniae coli converge on the base of the appendix
What is the blood supply to the appendix?
Appendicular artery (branch of inferior division of ileocolic artery)
Which parts of the colon have mesenteries?
Transverse and sigmoid
What does the colon sit anteriorly to?
Ascending- right kidney and inferior liver
Transverse- right kidney, small intestine, left kidney, pancreas
Descending- left kidney, tail of pancreas, spleen
Sigmoid- rectum
What is the blood supply to the colon?
Ascending and proximal 2/3rd of transverse are supplied by SMA; ileocolic, right colic and middle colic
Remainder from IMA; left colic and sigmoid
Anastomic branches between the two are marginal artery.
How big is the liver?
1.5kg
1500ml of blood per minute
Anterior surface covers ribs 6-10 on the right and 6+7 on the left
Right surface extends from ribs 7-11
Where is the falciform ligament?
Over anterior surface, near the middle, down to the notch made by ligamentum teres. To the left of gall bladder fundus. Upper attachment of falciform ligament sweeps to the left and is known as triangular ligament, sweeps to the right and becomes upper layer of coronary ligament.
Describe the posterior surface of the liver (H shaped pattern)
Right limb of H- inferior vena cava and gall bladder
Cross piece of H- porta hepatis
Left limb- ligamentum venosum and ligamentum teres
What is the only part of the posterior surface of the liver that is in the lesser sac?
Caudate lobe
What is in the porta hepatis?
Right and left hepatic ducts
Right and left branches of hepatic artery
Portal vein
Surrounded by lesser omentum
Lie in order vein artery duct with ducts in front
What are the lobes of the liver?
Left- left of falciform ligament
Caudate- posteriorly between inferior vena cava and fissure for ligamentum venosum
Quadrate- between gall bladder fossa and fissure for ligamentum teres
Right- right of falciform ligament
Describe the liver segments from right to left, top to bottom
Anterior: 7, 8 4, 2, 6, 5, 4 ,3
Posterior: 2,4, 1, 8, 3 4, 5, 6
Describe the blood supply to the liver
2 sources
Hepatic artery (arterial) (divides into right and left in porta hepatis- Y shaped). Right branches-> anterior and posterior segmental branches
Left branch-) medial and lateral segmental branches
Portal vein (venous) also divides into right and left in porta hepatis but T shaped
Venous drainage by 3 main hepatic veins which drain into IVC
What are the anatomical variations of blood supply to the liver?
Common hepatic artery may arise form SMA or aorta (instead of coeliac trunk), in which case it runs BEHIND the portal vein
Right and left hepatic branches may arise from SMA or left gastric arteries which may either replace existing arteries or exist in addition
What is the lymph drainage of the liver?
nodes in porta hepatis (also receive gall bladder)
Drains into retropyloric nodes and then coeliac nodes
Describe the histology of the liver
hexagonal lobule
Central vein
Corners have small branches of hepatic artery and bile duct
Acinus- diamond shaped area with ventral veins and portal canals
Describe the flow of bile
Produced in liver Collected by bile canliculi in lobules Drains into left and right hepatic ducts Drains into common hepatic duct Joined by cystic duct to form common bile duct
Why do you get RUQ pain in cholecystitis
Gallbladder fundus projects beyond lower border of liver and touches parietal peritoneum around right costal margin
Fundus lies just to the left of hepatic flexure
What is the body of the gallbladder in contact with?
Liver
Duodenum
What does the gall bladder neck become?
Cystic duct-> joins common bile duct
What is the blood supply to the gall bladder?
Small hepatic vessels
Cystic artery (usually from right hepatic but may be from main hepatic, left hepatic or gastroduodenal)
Thrombosis of cystic artery DOES NOT lead to ischaemia (in contrast to appendiceal artery)
Where is the cystic artery found?
Calot’s triangle
Formed by liver, common hepatic duct and cystic duct
What is the usual anatomy of the common hepatic duct in relation to blood supply
4cm long 4mm wide
Lies on free edge of lesser omentum
Right branch of hepatic artery passes behind
Cystic duct meets common hepatic 1cm above duodenum
What is the usual anatomy of the bile duct in relation to blood supply
8cm long 8mm wide
Upper 1/3 lies in free edge lesser omentum in front of poertal vein and to the right of hepatic artery
Middle 1/3 runs behind 1st part of duodenum, IVC behind
Lower 1/3 between head of pancreas and second part of duodenum in front of right renal vein. Joins pancreatic duct at hepatopancreatic ampulla
What is the nerve supply to the biliary tract?
Parasympathetic from vagal trunk
Sympathetic from coeliac ganglia
Hormonal
Some fibres run with phrenic nerve (reason for referred shoulder pain)
Describe the course of the portal vein
Superior mesenteric vein becomes portal vein when it receives splenic vein behind pancreas
Lies in front of IVC
Travels between two layers of lesser omentum. Lies behind bile duct and hepatic artery. Bile duct curves BEHIND the pancreas and hepatic artery curves IN FRONT of pancreas.
What is the ligamentum teres?
The obliterated remains of the left umbilical vein (often not completely obliterated)
Describe the structures immediately surrounding the pancreas
Head: anterior to; IVC, right and left renal veins, level of L2, bile duct
Neck: Superior mesenteric vein, transverse mesocolon attached
Body: Anterior to; left renal vein and aorta, left crus of diaphragm, left psoas muscle, hilum of left kidney. Crosses origin of superior mesenteric artery
Tail: touches hilum of spleen, accompanied by splenic artery and vein
Which parts of the pancreas are drained by the pancreatic duct?
All except uncinate process and lower part of the head which are drained by accessory duct
(pancreas develops as 2 different buds)
What is the blood supply to the pancreas?
Splenic artery
Superior and inferior pancreatoduodenal arteries
What size is the spleen?
1x3x5 inches weighs 7 ounces and lies between the 9th and 11th ribs