Aorta, SMA, IMA, CT😊

Abdominal Aorta

• Extension: T12 → L4

Branches

• Ventral branches

ㅤ	ㅤ
Celiac Trunk	Lower border of T12
Superior Mesenteric Artery	Lower border of L1
Inferior Mesenteric Artery	Body of L3









Mnemonic: Common (CIA) Inferior People (Inf phre) are Ready (rena) to Go (gona) Middle (middle supra) east

• Dorsal branches
• Lumbar Artery (4 pairs)
• 5th paired lumbar artery:
• If present, arises from median sacral artery
• Single Median Sacral Artery

• Lateral branches
• Inferior Phrenic Artery
• Middle Suprarenal Artery
• Renal Artery
• Gonadal Artery (testicular/ ovarian artery)

• Terminal branches
• Common Iliac Artery

Coeliac Trunk Branches

• Mnemonic:
• C Trunk → Drunk CPM SP is a common man
• Common man (Common hepatic)
• Left ist (CPM → LGA)
• SP (swayam pongi → splenic)

• The coeliac trunk supplies blood to the stomach, spleen, liver, and pancreas.

It has 3 main branches.

1. Left Gastric A.

• Runs along the lesser curvature of the stomach.

• Smallest branch

• Largest/main Artery of stomach

• Supplies the esophagus with esophageal branches
• pierces diaphragm at T10

2. Splenic A.

• Located behind the stomach.

• Known as a tortuous artery.

• Branches:
• Short gastric artery
• Left gastroepiploic artery
• Pancreatic branches → Pancreatica Magna
• Supplies Neck, body and tail of pancreas
• Hilar branches

3. Common Hepatic A. Branches

• Ligation or occlusion → Impaired flow to RGA and Right gastroepiploic artery.

a. Proper Hepatic Artery

• Branches:
• Right hepatic artery: Supplies cystic artery → Supplies GB
• Left hepatic artery
• Right gastric artery
• (Hepatic artery proper > Common Hepatic Artery)

b. Gastroduodenal Artery

• Located behind 1st part of the duodenum

• Bleed in Posterior Duodenal ulcer

• Branches:
• Right gastroepiploic artery
• Superior pancreaticoduodenal artery
• Supplies Head of pancreas

Blood supply to duodenum

• Arterial Supply to 1st 2 cm of Duodenum (Duodenal Cap)
• Hepatic artery
• Right gastric artery (RGA)
• Gastroduodenal artery
• Right gastroepiploic artery

Dunbar Syndrome

• Celiac artery arises at a higher level
• Gets compressed by the median arcuate ligament
• Compressed celiac trunk.

• Note: Normally arises just below the aortic opening.

Superior Mesenteric Artery (SMA) Branches

• Supplies Midgut
• Extends up to the (R) 2/3rd of the transverse colon.

1. Jejunal & ileal branches

2. Inferior pancreaticoduodenal artery

3. Middle colic artery
1. L branch
2. R branch 🅳

4. Right colic artery
1. Ascending branch 🅳
2. Descending branch 🅳

5. Ileocolic artery
1. Ascending branch 🅳
2. Descending branch → anastomoses with trunk of SMA

Note

• 🅳 = Arteries involved in Marginal Artery of Drummond Anastomosis

• Right colic artery
• Most commonly absent artery of the gut.

Inferior Mesenteric Artery (IMA) Branches

1. Left colic artery

2. Sigmoidal artery

3. Superior rectal artery
• Continuation of IMA

Arc of Riolan:

• Connects proximal SMA and proximal IMA

• Anastomose:
• Ascending br. Left colic artery (IMA) → (L) middle colic (SMA)
• Note: IMA > SMA

Watershed Area

• Lie between 2 arterial supplies with minimal overlap.

Internal Iliac Artery (IIA)

• Anterior division: Save MR with IVIG in IP

Origin

• Mnemonic: Common ileac → Lady called Ila
• Externally she is a common female → External Iliac: femoral Art
• Internally
• she likes to wear silky in the back → Posteriorly: SILK
• show her pelvic areas Infront → Umbilicus, Bladder, Uterus, Vagina, Middle Rectal, etc

Common Iliac Artery (CIA)

• divides at lower border of L5 into
1. ILA
2. ELA

Internal Iliac Artery

• Divides after passing through Greater Sciatic notch into
1. Anterior Division
2. Posterior Division

Posterior Division (SIL/SIG branches)

• Superior Gluteal Artery

• Iliolumbar Artery

• Lateral Sacral Arteries

Anterior Division

• Common Branches
• Superior Vesical Artery
• Remnant of Proximal Umbilical Artery
• Middle Rectal Artery
• Obturator Artery
• Internal Pudendal Artery
• Inferior Gluteal Artery
• largest branch

• Males only
• Inferior Vesical Artery
• Supplies:
• Base of Bladder
• Prostate Gland
• Seminal Vesicles
• May give off artery to Ductus Deferens
• Artery to Ductus Deferens (may arise from SVA)

• Female only
• Uterine Artery
• Vaginal Artery supplies:
• Base of Bladder
• Terminal Ureter
• Vaginal Wall

Umbilical Artery Remnants

Allantois/Urachus Remnant

• Allantois → (obliterated) → Urachus
• becomes MEDIAN umbilical ligament
• located at apex of bladder.
• Mneumonic: An Orange (urachus)

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NOTE: Umbilical Remnants:

• Umbilical arteries → 2
• Obliterate before birth.
• Remnant:
• Proximal part → Superior vesical artery.
• Distal part → Obliterated umbilical artery → Medial umbilical ligament
• NOTE
• Lateral umbilical ligament
• Remnant of Inferior Epigastric vessels

• Umbilical vein (left) → 1
• Obliterates after closure of umbilical artery.
• Remnant: Ligamentum teres hepatis.

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Urine from umbilicus:

• Due to persistence of urachus or Allantois.

• Leads to weeping umbilical cord
• (urine dribbling from umbilicus)

Meconium from umbilicus:

• Due to persistence of Entire Vitello intestinal duct.

• NOTE: Proximal part only → Meckel’s diverticulum

Portal Vein Formation

• Behind the neck of pancreas

• At the level of L2
• Same level of thoracic duct origin from cisterna chyli

• By union of:
• Splenic vein
• Superior mesenteric vein

Portosystemic Anastomosis Sites

ㅤ	Portal circulation	Systemic circulation
Oesophageal varices (Lower 1/3)	Oesophageal branch of Left Gastric Vein	Oesophageal branch of Accessory Hemiazygous Vein
Rectal varices	Superior Rectal Vein	Middle and Inferior Rectal Veins
Caput medusae	Paraumbilical vein	Superficial veins of anterior abdominal wall