Cracking: Applied surgical anatomy Flashcards
(106 cards)
Abdominal aorta: Where does it begin and end?
Starts at T12 as it transverses the diaphragm Ends at L4 where it bifurcates into the common iliac arteries
Abdominal aorta: What are it’s relations?
Passes in the midline in the retroperitoneum Anterior: Left renal vein, pancreas, lesser sac Posterior: anterior longitudinal ligament, vertebral bodies Right: Cisterna chyli, thoracic duct, azygos vein Left: duodenojejunal flexure
Abdominal aorta: What are it’s branches and at what level do they branch?
Paired: T12 Inferior phrenic artery ->adrenal gland and diaphragm T12 Adrenal artery -> Adrenal gland L2 Renal artery -> Kidneys, adrenal glands, ureter L2-3 Gonadal artery -> Gonads, ureters L2-3 Lumbar arteries (4 pairs) -> lumbar musculature L4 Iliac arteries (terminal) -> legs and pelvic viscera Unpaired: T12 Coeliac trunk - foregut + liver, spleen, pancreat L1 SMA - midgut L3 IMA - hindgut L4 Median sacral artery - sacrum
Anal Canal: What is the embryology?
Starts off as an endodermal tube Ectoderm invaginates and meets the endoderm to form the anal canal So, distal half is ectoderm (proctoderm) derived, whilst the proximal half is endoderm derived
Anal Canal: What is the anatomy? - relations
Posterior: anococcygeal body and coccyx Laterally: ischiorectal fossa Anterior: perineal body (M&F), penis (M), Vagina (F)
Anal Canal: What is the anatomy? - structure above v below the dentate line
Anal Canal: What is the anatomy? - sphincters
External sphincter - voluntary control. 3 parts: subcutaneous, superficial, deep (parts)
+Puborectalis sling around anal canal/lower rectum -> acute angle to help maintain continence
Internal sphincter - autonomic control
Anal Canal: What is the sequence of events in defecation?
Faeces arrive at the rectum from emptying of the distal large bowel -> urge to defecate
Intra-abdominal pressure rises with increased in diaphragmatic and abdo muscle pressures
Anal sphincterns voluntarily relax
Faeces are evacuated
Biliary system: anatomy?
Divided into intra-hepatic and extra-hepatic systems
Biliary tree starts intra-hepatically as bile canaliculi which divide into bile ductules and small interlobular tributaries of the bile ducts. These join each other to form larger ducts.
R hepatic duct drain the right lobe and the left the left. These two ducts leave the liver at the porta hepatis to become extra-hepatic
The then join (amalgamates) to form the common hepatic duct
This then joins (accepts) the cystic duct to for the common bile duct
The CBD with the hepatic artery (left) and portal vein (behind) travels in the free edge of the lesser omentum at the porta hepatis
At the distal edge it joins (accepts) the pancreatic duct
The CBD terminates at the sphincter of Oddi/ampulla of Vater which opens into the medial aspect of the second part of the duodenum
Biliary system: Relations of the common bile duct?
It is 8cm in length
Diameter: 6mm = upper limit of normal (but get’s 1mm larger every 10 years after 60yo + is larger post cholecystectomy)
Travels in the free edge of the lesser omentum in the porta hepatis with the common hepatic artery (left) and the portal vein (behind)
Biliary system: CBD is divided into three parts…
- First part: anterior to the opening of the Lesser sac
- Second part: Posterior to the first part of the duodenum
- Third part: Posterior surface of the head of the pancreas
Biliary system: what is the histiological layout of the biliary system?
Liver is divided into functional units - lobules
At the periphery of each are the portal triads - bile ductule, terminal hepatic artery branch, terminal portal vein tributary
Each lobule had a central terminal hepatic venule
Blood flows from the portal triad (portal vein & hepatic artery), in the sinusoids, to the central venule. Peripherally to centrally.
These venules then transport blood to the hepatic vein
Bile flows through the canaliculi in the opposite direction to the portal triads peripherally
Biliary system: Gallbladder anatomy
- Pear shaped viscus
- Lines with columnar epithelium
- Contains some smooth muscle in the wall
- Can hold 50mL bile
- Consists of fundus, body, neck
- Lies in the gallbladder fossa attached to ventral surface of the right lobe of the liver
- Neck is continuouse with the systic duct, a small diverticulum at this point, Hartmann’s pouch, is where stones can impact
Arterial supply - cystic artery
Venous drainage - snall veins into the substance of the liver
Lymphatic drainage - cystic node in Calot’s triangle
Biliary system: What is pringle’s manoeuvre?
Place a clamp over the free edge of the lesser omentum and occlude the vessels descrived above
Useful, temporary measure for controlling heavy bleeding from liver, e.g. trauma, by occluding the liver’s blood supply, because it can be done quickly
Biliary system: What is Calot’s triangle?
Triangle formed by the liver, Common hepatic duct, Cystic duct
The cystic artery runs within it.
It is important in identification of the cystic artery in laparoscopic cholecystectomies
Blood supply to the heart:
Anatomy of Right Coronary Artery
Arises from right (anterior) aortic sinus
Runs between pulmonary trunk and Rt auricle
Gives off marginal branch @junction of posterior interventricular groove and AV sulcus (which descends over the front of the ventricle),
and continues as the posterior interventricular artery continueing in the interventricular groove and anastomoses with anterior interventricular artery
It supplies the right ventricle, SAN (60%) and AVN, and part of the left ventricle

Blood supply to the heart:
Anatomy of Left Coronary Artery
Arises from the left (posterior) aortic sinus and divides into circumflex and anterior interventricular (left anterior descending)
Circumflex travels in AV sulcus to anastomose with the RCA
the anterior interventricular (LAD) travels in the interventricular groove to anastomose with the posterior interventricular artery

Blood supply to heart: Venous drainage
All V except for anterior cardiac V drain into coronary sinus which opens into post wall of R atrium
Anterior cardiac V runs across surface of R ventricl and drains directly into r atrium
Tributaries:
- Great cardiac V: travels with anterior interventricular artery and drains into left prox aspect of CS
- Middle cardiac V: travels with posterior interventricular artery and drains into CS
- Small Cardialc V : drain proximally into CS (Right marginal vein travels along the interior surfaceof heart and drains into the SCV)

The Diaphragm:
Anatomy
- Consists of peripheral muscular part and inserts via central tendon which fuses with the pericardium
- Bi-domes, reaching the fifth rib at its highest extent
- 2 crura - sites of origin of the diaphragm:
- R crus - from first 3 lumbar vertebrae
- L crus - from first 2 lumbar vertebra
- Right crus - sling around oesophagus and prevents reflux
- Medial and lateral arcuate ligaments are lateral to crura, contribute to origin of diaphragm
- Supplied by phrenic nerve (C3,4,5 keeps the diaphragm alive)
The Diaphragm: Development
Develops from septum transversum, pleuroperitoneal membranes, paraxial mesoderm of abdo wall and oesophageal mesenchyme
Spetum transversum, which initially forms an embryonic partition between thorax & abdo (emb wk 5-7) -> Central tendon
Crura of the diaphragm are derived from foregut mesenchyme
The Diaphragm: Diaphragmatic Hernias
through persisting pleuroperitoneal communications (where above contributions fail to fuse)
Morgani hernia - through foramen of M - into anterior mediatinum
Bonchdalek hernia - through foramen of B - posteriorly
diagnosed by CT
The Diaphragm: Openings
- T8 - IVC, and right phrenic nerve
- T10 - Oesophagus, and vagus nerve
- T12 - Abdominal aorta, and thoracic duct + azygos vein
Subcostal nerve - under lateral arcuate ligament
Sympathetic chain - behind medial arcuate ligament
Left phrenic nerve - pierces muscular portion of diaphragm
Great, lesser, least splanchnic N - pierces crura
The Diaphragm: Functions
- Main muscle of respiration
- Aids venous return to <3 (intermittent increased intra-abdo pressure on resp)
- Straining - defecation and micturition
- Support to vertebral columm
Femoral Triangle: Boundaries
- Superiorly: inguinal ligament
- Medially: medial border of adductor longus
- Laterally: medial border of sartorius
- Roof: Fascia lata
- Floor (M->L): adductor longus, adductor brevis, pectineus, iliopsoas


