Abdomen Flashcards
Abdominal wall - anterior layers
Skin Camper's fascia Scarpa's fascia external oblique internal olblique transversus abdominis transversalis fascia 2 layers of peritoneum
External oblique
origin: ribs 5-12
insertion: iliac crest and pubic tubercle
innervation: thoracoabdominal nerves
Internal oblique
origin: inguinal ligament, iliac crest, lumbodorsal fascia
insertion: ribs 10-12
innervation: thoracoabdominal nerve
Transversus abdominis
origin: inguinal ligament, costal cartilage, iliac crest and thoracolumbar fascia
insertion: conjoint tendon, xiphoid process, linea alba and pubic crest
innervation: thoracoabdominal muscles, subcostal
Rectus abdominis
origin: Crest of pubis
insertion: xiphoid process and sternum and costal cartilage 5-7
innervation: thoracoabdominal nerves
Pyramidalis
origin: pubic crest, pubic symphysis
insertion: linea alba
innervation: subcostal nerves
Rectus sheath
Formed by the aponeurosis of three flat muscles
Anterior wall - aponeurosis of external oblique and internal oblique
posterior wall - aponeurosis of internal oblique and transversus abdominis
ARCUATE LINE - midway from umbilicus to pubic symphysis where the posterior wall also lies anterior to the rectus sheath
Posterior abdominal wall
Quadratus lumborum
Psoas major
psoas minor
Quadratus lumborum
origin: iliac crest and iliolumbar ligament
insertion: transverse process of L1-L4
innervation: T12- L4
Psoas major
origin: T12-L5
insertion: Lesser trochanter
innervation: L1-L3
Psoas minor
origin: T12, L1
insertion: superior ramus of pubis
innervation: L1
action: flexion fo vertebral column
Fascia of the posterior wall
Psoas fascia - encloses psoas major & minor
thoracolumbar fascia - divided into 3 layers, anterior, middle and posterior layer
Peritoneum
Continous layer divided into parietal and visceral peritoneum
Squamous epithelial cells from mesothelium
Parietal peritoneum
Somatic sensation thus well localised
sensitive pain, laceration, temperature
Visceral peritoneum
Splanchnic mesoderm origin
poorly localises, referred to pain in dermatomes
Sensitive to chemical and stretch
Intraperitoneal organ
Stomach
Liver
Spleen
GI tract
Retroperitoneal organ
primary vs secondary Suprarenal glands Aorta Duodenum (except 1st part) Pancreas (except the tail) Ureters Colon (ascending & descending) Kidneys Oesophagus Rectum
Peritoneal reflections
Mesentery
Greater omentum
Lesser omentum
Mesentery
Double layer of the visceral peritoneum Connects the organs to the posterior abdominal wall Small bowel Transverse colon Sigmoid mesocolon mesoappendix
Greater omentum
Greater curvature of stomach and proximal part of duodenum to anterior surface of transverse colon
Act as immunological barrier
Lesser omentum
Lesser curvature of stomach & proximal part of duodenum to liver
Hepatogastric ligament & hepatoduodenal ligament
Greater sac
Divided by transverse mesocolon
Supracolic - stomach, liver and spleen
Infracolic - small intestine, colon
Lesser sac
posterior to stomach and lesser omentum
connected to greater sac via EPIPLOIC FORAMEN
situated posterior to the free edge of the hepatoduodenal ligament
Peritoneum in pelvis
Male - rectovesical pouch - CLOSED
female - vesicouterine pouch and rectouterine pouch (pouch of douglas)
Inguinal canal - borders
Floor - inguinal ligament, lacunar ligament medially
Anterior - internal oblique then external oblique aponeurosis
Posterior - transversalis fascia
roof - transversalis fascia, transverse abdominis and internal oblique
Inguinal canal content
Spermatic cord
Ilioinguinal nerve
Spermatic cord content
3 fascia - external spermatic (external oblique aponeurosis), cremaster muscle & fascia (internal oblique aponeurosis) and internal spermatic fascia (transversalis fascia)
3 arteries - testicular, cremaster, vas
2 nerves - autonomic, genital branch of genitofemoral nerve
4 others - pampiliform, lymphatics, vas deferens, tunica vaginalis
Formation of inguinal canal
GUBERNACULUM guides the descend of testis from posterior abdominal wall to scrotum Processus vaginalis (part of peritoneum) degenerates but if not - leads to indirect hernia
GI Tract - oesophagus
approx 25cm in length
C6 to T11 and pierces diaphragm at T10
attached to the phrenoesophageal ligament
consists of internal circular and external longitudinal muscles
Upper oesophageal sphincter - cricopharyngeus muscle, striated muscle
Lower oesophageal sphincter - PHYSIOLOGICAL (acute angle of entry, gets compressed with raised IAP, folds of mucosa and right crus of diaphragm
Supplied by inferior thyroid, aorta, left gastric artery
Drains into portal circulation via left gastric vein and azygous vein
GI tract - Stomach
Cardia - fundus - body - pylorus (ANATOMICAL SPHINCTER)
Greater curvature - reaches the pyloric antrums
Lesser curvature: has the angular notch which divives the body and pylorus
Supplied by left gastric (coeliac trunk), right gastric (CHA), right gastro omental (gastroduodenal), left gastro omental (splenic)
Drains to Left and & right gastric - hepatic portal vein
Gastro omental into SMV
GI tract - Small interstine
Duodenum
Jejunum
Ileum
Duodenum
4 parts
1st - intraperitoneal, attached to liver by hepatoduodenal ligament, common area for ulcers
2nd - retroperitoneal, major duodenal papilla (posteromedial wall)
3rd - crosses over IVC and aorta, posterior to SMA
4th - duodenojejunal flexure, suspensory muscle of the duodenum
supplied by gastroduodenal artery and inferior pancreaticoduodenal artery (SMA)
Jejunum and ileum
attached the posterior wall by mesentery
starts at the duodenojejunal flexure and ends at ileocaecal junction
Jejunum - thicker wall, longer vasa recta, less arcadesm red
ileum - thinner wall, shorter vasa recta, more arcades and pink
Caecum
Start of colon, inferior to IC junction
intraperitoneal
Appendix
Vermiform shaped blind end tube located posteromedial to caecum, at the end of tinea Pre ileal - 1 (anterior) Post ileal - 2 (posterior) sub ileal - 3 (alond) pelvic - 5 subcaecal - 6 (below caecum) para caecal - 10 (lateral to caecum) retro caecal - 11 (posteiror to caecum)
Colon
It has omentum appendices, teniae coli, haustra
Ascending - retroperitoneal up to hepatic flexure
Transverse - mesocolon up to splenic flexure
Descending - retroperineal up to sigmoid flexure
Sigmoid - intraperitoneal up to rectosigmoid junction
Supplied by SMA (right colic, middle colic) and IMA (left colic, sigmoid)
Watershed area - marginal artery of Drummond
Rectum
Stores faeces, 15cm long begins at S3
superior third covered by peritoneum from 3 sides and middle third covered on anterior side
Supplied by Superior rectal (IMA), middle rectal (IIA), inferior rectal (pudendal)
Drains into superior/middle/inferior rectal veins where superior one drains into IMV thus postal system
sympathetic - lumbar splanchnic - inferior hypogastric plexus
parasympathetic - S2-S4
Anal canal
located at the anal triangle, right and left ischioanal fossa
internal sphincter - involuntary
external sphincter - voluntary puborectalis muscles
ABOVE pectinate line - endoderm origin, columnar epithelium, organised into anal column and anal valve; supplied by SRA, SRV
BELOW pectinate line - ectoderm origin, non keratinised stratified squamous epithelium until intersphincteric groove - skin; supplied by IRA/IRV
Liver - surface
Intraperitoneal organ
4 ligaments - falciform ligament (ligamentunm teres - umbilical vein), coronary ligaments, triangular ligaments, lesser omentunm (hepatoduodenal/hepatogastric)
3 recesses - subphrenic, subhepatic and morison’s pouch
2 supply - hepatic portal and systemic
Liver lobal anatomy
2 lobes divided by falciform ligament
2 further accessory lobes
caudate - separated by IVC and ligamentum venosum (remnant of ductus venosus)
quadrate - separated by ligamentum teres (umbilical vein) and lies with the gall bladder
anatomically part of right but functionally part of left lobe
Can also be divided in 8 hepatic segments
Gall bladder
Located at L1
Stores bile, connected through the cystic duct and joins the CBD
Fundus - body - neck - Hartmann’s pouch - cystic duct
Supplied by cystic artery (branch of hepatic artery)
Vagus nerve stimulates as well but main stimulant is Cholecystokinin
Biliary tree
Right and left hepatic duct
Common hepatic duct (+ cystic duct )
Common biliary duct (+ pancreatic duct)
Ampulla of Vater
Pancreas
Retroperitoneal
Exocrine and endocrine organ
Head, uncinate process, neck, body and tail (intraperitoneal)
Lies posterior to SMA/SMV
Tail is closely related to spleen via splenic artery and splenorenal ligament
supplied by pancreatic branch of splenic, superior & inferior pancreatoduodenal (gastroduodenal)
Spleen
Immunological & haematological organ
Intraperitoneal
Ligaments - splenorenal ligament, gastrosplenic ligament
1 x 3 x 5 inches, 7 ounces (200g), ribs 9-11
Splenic artery has segmental supply thus subtotal resection is possible
Adrenal glands
Retroperitoneal organ, endocrine organ
Cortex - zona glomerulosa (mineralocorticoid), zona fasciculata (glucocorticoid), zona reticularis (sex hormones)
Medulla - chromaffin cells - adrenaline
Supply - 3 arteries
Superior adrenal - inferior phrenic artery
Middle adrenal - aorta
Inferior adrenal - renal artery
Kidneys
Retroperitoneal organ - T12-L3
Clear toxin from circulation & maintain circulatory homeostasis (volume & electrolyte)
Complex fascia - capsule, perirenal fat, renal fascia, pararenal fat
Cortex & medulla
Medulla - renal pyramids - calyx - pelvis - ureter
Supply - renal artery - interlobar - arcuate
Drains into renal veins (left side drains adrenal & gonadal as well)
Aorta
Ascending aorta - left and right coronary
Arch - brachiocephalic, CCA, subclavian
Thoracic - bronchial, mediastinal, oesophageal, pericardial, superior phrenic, intercostal arteries
Abdominal - Inferior phrenic, Coeliac(T12), SMA(L1), Middle adrenal, renal, gonadal (L2), IMA(L3), Median sacral (L4), CIA(L4); lumbar arteries
Coeliac trunk
at T12
Common hepatic artery - hepatic artery proper (right gastric, R&L hepatic, cystic), gastroduodenal (superior pancreaticoduodenal, right gastro omental)
Left gastric artery - oesophageal
Splenic artery - left gastro omental, short gastric, pancreatic branches
Superior mesenteric artery
at L1, supplies the midgut anterior aspect - pyloric part of stomach, splenic vein, NECK of pancreas posterior aspect - left renal vein, duodenum, uncinate process of pancreas Major branches: Inferior pancreaticoduodenal artery Right & middle colic Ileocolic Jejunal & ileal arteries
Inferior mesenteric artery
at L3, supplies the hindgut, retroperitoneal
main branches:
Left colic; Sigmoid; Superior rectal
Anastomosis with middle colic - Marginal artery of Drummond
Venous drainage
IVC
Hepatic portal system
Inferior vena cava
Formed by CIV at L5
Drains - Lumbar veins, right gonadal, right adrenal, right and left renal, inferior phrenic and hepatic veins
Portal venous system
Drains the GIT content and supplied to liver
At L2
Formed by SMV & Splenic
Drains R&L gastric, cystic, para-umbilical veins
Splenic - short gastric, left gastroomental, pancreatic, IMV
SMV - right gastroomental, anterior and posterior inferior pancreaticoduodenal, jejunal, ileal, ileocolic, right & middle colic
Portosystemic anastomosis
Oesophageal - left gastric and azygous
Rectal - superior rectal and inferior rectal
Retroperitoneal - mesenteric to reperitoneal
Paraumbilical - portal vein to anterior abdominal wall
