ABDOMINAL ANATOMY Flashcards
You are assisting in a nephrectomy using a posterior approach. The consultant’s previous patient had a complication following the operation and today they are being more cautious than usual. Which one of the following is important during this approach?
A The adrenal glands are at easy risk of injury
B The parietal pleura does not extend below the twelfth rib
C The perinephric fat surrounds the renal fascia
D The renal artery lies anterior to the renal vein in the anatomical position
E The subcostal neurovascular bundle is relatively protected from risk of injury
ANSWER: E - The subcostal neurovascular bundle is relatively protected from risk of injury
The subcostal neurovascular bundle is relatively protected from risk of injury because it lies in the costal groove.
The renal fascia of Gerota surrounds the perinephric fat, which lies outside the renal capsule. The renal artery is posterior to the renal vein. The adrenal glands are anatomically well protected. They lie anterosuperior to the upper part of each kidney, within their own compartment of the renal fascia. Care must be taken during a nephrectomy to avoid damage to the adrenals, but these are not easily damaged by a careful surgeon using a posterior approach.
The lower border of the parietal pleura crosses the twelfth rib at the lateral border of the erector spinae, and passes in horizontally to the lower border of the twelfth thoracic vertebrae. There is, therefore, a triangle of pleura in the costovertebral angle below the medial part of the twelfth rib, behind the upper pole of the kidney
A 35-year-old builder has a left inguinal hernia repair. During the operation, the external oblique is opened and you commence lifting the spermatic cord.
Which one structure lies within this?
A Cremasteric artery
B External spermatic fascia
C Femoral branch of the genitofemoral nerve
D llioinguinal nerve
E Lipoma of the cord
ANSWER: A Cremasteric artery
Nine structures lie within the spermatic cord: three arteries (testicular, cremasteric, artery to the vas deferens); three nerves (genital branch of the genitofemoral nerve, sympathetic fibres, ilioinguinal nerve - this is outside the cord but travels with it and three other structures (pampiniform plexus, vas deferences, lymphatics). There are three covering fascial
layers - external and internal spermatic and cremasteric fascia.
The external spermatic fascia is a thin membrane covering the spermatic cord and is derived from the aponeurosis of the external oblique. It surrounds but is not contained within the cord.
The ilioinguinal nerve travels within the inguinal canal but not within the spermatic cord. The genital branch of the genitofemoral nerve travels within the spermatic cord rather than the femoral branch. Lipomas of the cord are sometimes found during inguinal hernia repairs but they are not contained within the cord.
A 25-year-old football player is undergoing an inguinal hernia repair. First Camper’s and then Scarpa’s fascia are divided and the first muscle layer is visualised.
What would the surgeon note to identify the superficial inguinal ring?
A A W-shaped defect in the external oblique
В Intercrural fibres
C The conjoint tendon and the transversalis fascia
D That the ilioinguinal nerve is within the spermatic cord
E That the inferior epigastric vessels are lateral to the deep inguinal ring
ANSWER: В Intercrural fibres
The visible landmark for the superficial inguinal ring are the intercrural fibres that run at right angles across the external oblique aponeurosis. The inguinal canal with its borders is shown in the image below, with the deep inguinal ring seen laterally and the superficial ring seen medially at either end.
The superficial inguinal ring is a triangular hiatus in the external oblique aponeurosis. These form the posterior wall of the inguinal canal - the transversalis fascia laterally and the conjoint tendon medially. The ilioinguinal nerve travels through the inguinal canal with the spermatic cord but not inside it. The inferior epigastric vessels are medial to the deep inguinal ring
You are a Foundation Year 2 (FY2) student assisting in a laparotomy for small bowel obstruction. While opening the abdomen via a midline laparotomy, the consultant points out the most superficial fascial layer, which is fatty. She asks you what this fascia is called. What is the most likely name of the structure described?
A Camper’s fascia
В Scarpa’s fascia
C Colle’s fascia
D Dartos fascia
E Fascia lata
ANSWER: A Camper’s fascia
The superficial fascia of the anterior abdominal wall is divided into a superficial adipose layer known as Camper’s fascia and a deeper membranous layer known as Scarpa’s fascia. Camper’s fascia is fatty to varying degrees and is the more superficial, and therefore is the correct answer here. The layers of the anterior abdominal wall are: skin, subcutaneous tissue, superficial fascia (Camper’s fascia and Scarpa’s fascia), external oblique muscle, internal oblique muscle, transversus abdominis muscle, transversalis fascia, preperitoneal fatty tissue,and peritoneum. These are clinically important to know for all abdominal surgery.
Scarpa’s fascia is the deeper layer to Camper’s fascia and is thin and membranous. It contains very little, or no, fat and so is not the correct answer here. Scarpa’s fascia continues below the inguinal ligament and fuses with the fascia lata of the thigh. It also forms the fundiform ligament of the penis and is known as Colle’s fascia once it advances posteriorly along the perineum.
Colle’s fascia is the continuation of Scarpa’s fascia in the perineum. It is the deeper membranous layer of the superficial perineal fascia. It attaches to the ischiopubic rami and the perineal membrane, which divides the prostate from the base of the penis.
The Dartos fascia is the continuation of Scarpa’s fascia into the scrotum. It contains smooth muscle fibres. The fascia lata is the deep fascia of the thigh and surrounds the muscles of the thigh. Scarpa’s fascia fuses with the fascia lata just under the inguinal ligament.
You are assisting during a Hartmann’s procedure. While dividing the anterior abdominal layers during the operation, your registrar points out a triangular structure, anterior to the rectus abdominis, which has its base on the pubis and is attached superiorly to the linea
alba. He remarks that this structure is sometimes absent.
What is the most likely name of the structure?
A Linea alba
B Plantaris muscle
C Diastasis recti
D Pyramidalis muscle
E Peroneus tertius
ANSWER: D Pyramidalis muscle
This is a small, triangular, vertical muscle that lies anterior to the rectus abdominis and attaches to the linea alba having originated at the front of the pubis and pubic symphysis. It is innervated by the ventral portion of T12 and supplied by the inferior and superior epigastric arteries. Its action is to tense the linea alba. It is naturally absent† in up to 12% of the population.
The linea alba (white line) is a fibrous structure running down in the midline from the xiphoid process to the pubic symphysis. Although it attaches inferiorly to a similar place, it is not triangular and has not been frequently reported to be absent. The linea alba is tensed by the pyramidalis muscle, which is the correct answer here.
Although the plantaris muscle has been noted to be absent in as much as 12% of the population, it is found in the superficial posterior compartment of the leg, and so would not be seen during a Hartmann’s procedure, which requires a midline laparotomy.
Peroneus tertius is a muscle in the lower leg that effects eversion and dorsiflexion of the foot, so it will not be seen during the operation described. However, it can be absent in up to 17% of the population.
Diastasis recti, or divarication, is not a structure, but a condition in which an abnormal distance is created between the right and left abdominal muscles - generally taken to be above 2 cm. It occurs due to the laxity of the linea alba, and risk factors include pregnancy and obesity. It is apparent on clinical examination by a prominent abdominal ridge seen
when a patient with the condition raises his/her head. It does not often require surgical repair.
You are scrubbed in during an inguinal hernia repair case on a 74-year-old man who presented as an emergency with bowel obstruction. During the operation you correctly identify the spermatic cord. Which one of the following structures is found outside the spermatic cord?
A Testicular artery
B Cremasteric artery
C llioinguinal nerve
D Pampiniform plexus
E Vas deferens
ANSWER: C llioinguinal nerve
The ilioinguinal nerve is a branch of the first lumbar nerve and accompanies the spermatic cord through the inguinal canal, exiting through the superficial inguinal ring. It is commonly seen overlying the cord, rather than within it.
The testicular artery is found in the spermatic cord and is one of three arteries that travels within it. A paired artery, it branches directly on each side from the abdominal aorta, below the origin of the renal arteries and passes downwards on the anterior surface of the psoas major to supply the testes.
The cremasteric artery is found in the spermatic cord and is one of the three arteries travelling within it. It is a branch of the inferior epigastric artery and supplies the cremaster muscle and scrotal skin. The pampiniform plexus is a network of veins found within the spermatic cord. It provides venous return from the testes and plays a part in testicular temperature regulation. A varicocele is an abnormal enlargement of this structure. The vas deferens is a muscular structure that does run within the spermatic cord and transports sperm from the epididymis to the ejaculatory duct. If inadvertently damaged during a hernia repair, it may contribute to infertility and the patient must be counselled regarding this during the consent process
You have been holding a retractor for an hour during an emergency laparotomy for small bowel obstruction. Your consultant notices that you are losing concentration and asks you to distinguish between intraperitoneal and retropertoneal structures. Which one of the following is an intraperitoneal structure?
A Descending part of duodenum
B Ascending part of duodenum
C Inferior vena cava
D Suprarenal glands
E Sigmoid colon
ANSWER: E Sigmoid colon
The sigmoid colon is suspended in the mesentery and is found within the peritoneal cavity. The organs of the abdominal cavity can be classified as intraperitoneal or retroperitoneal according to their relationship with the peritoneal membrane. Intraperitoneal organs are those that are within the peritoneal space and lined with peritoneum, and retroperitoneal are those that lie behind the space and are not lined with peritoneum. These organs are mainly close to the posterior wall of the abdomen.
The descending part of the duodenum is the second part of the duodenum and is retroperitoneal. Only the proximal first segment of the duodenum is intraperitoneal. he ascending part of the duodenum is the fourth part and is the longest section. It is crossed by the superior mesenteric artery and vein and is a retroperitoneal structure.
The inferior vena cava lies posteriorly to the main abdominal cavity and is therefore a retroperitoneal structure. Suprarenal glands, these endocrine glands produce varying hormones and are retroperitoneal glands, sitting on top of the kidneys and surrounded by Gerota’s fascia.
You are a surgical Foundation Year 2 (FY2) student observing an emergency small bowel resection in a patient with small bowel obstruction. You ask the registrar to explain the anatomical differences between the jejunum and ileum. Which one of the following statements is the most accurate?
A The jejunum is larger in diameter than the ileum and displays more prominent arterial arcades
B The ileum is mainly situated in the left lower quadrant and has thinner walls than the jejunum
C The jejunum lies mainly in the left upper quadrant of the abdomen and has less prominent arterial arcades than the ileum
D The ileum has less mesenteric fat, but more prominent plicae circularis (valvulae conniventes) when compared with the jejunum
E The ileum has thicker walls and less prominent plicae circularis in comparison with the jejunum
ANSWER: C The jejunum lies mainly in the left upper quadrant of the abdomen and has less prominent arterial arcades than the ileum
The jejunum is mainly found in the left upper quadrant of the abdomen and is characterised by less prominent arterial arcades and longer vasa recta when compared with the ileum. The jejunum is larger in diameter and has a thicker wall than the Ileum, but it is characterised by less prominent arterial arcades and longer vasa recta. The ileum does have thinner walls in comparison with the jejunum but is mainly found in the right lower quadrant of the abdomen. he ileum has more mesenteric fat and less prominent plicae circularis (mucosal folds) than the jejunum. The ileum has less prominent plicae circularis in comparison with the jejunum but has thinner walls.
You are teaching a group of medical students about the embryological anatomy of the abdomen when one student asks about the boundaries of the foregut. Which one of these abdominal structures is most closely related to the junction between
the foregut and the midgut?
A The origin of the superior mesenteric artery (SMA)
B Major duodenal papilla
C Head of the pancreas
D Distal third of transverse colon
E The origin of the coeliac trunk
ANSWER: B Major duodenal papilla
The foregut begins at the mouth and ends just inferior to the major duodenal papilla, where it gives way to the midgut. he SMA originates from the anterior abdominal aorta anterior to L1. It supplies the midgut, which begins inferior to the major duodenal papilla.
The head of the pancreas is closely related to the duodenum as it lies within its concavity. The major duodenal papilla, below which point the foregut ends and midgut begins, is the point at which the common bile duct and pancreatic duct empty into the duodenum. Therefore, the head of the pancreas is closely related to the junction between foregut and midgut but the major duodenal papilla is a more accurate answer.
The distal third of the transverse colon is the point at which the hindgut begins and is not related to the foregut and midgut. The coeliac trunk arises from the abdominal aorta immediately below the hiatus of the diaphragm at T12. It originates just above the superior mesenteric artery and supplies the foregut but is not related to the junction of the foregut and midgut.
You are a CT1 doctor working in a hepatobiliary ward when you review a computed tomography arterial portography (CTAP) scan of a patient with portal vein thrombosis. As you scroll through the images you try to remember the anatomy of the portal vein. Which one of these statements is the most accurate with regard to the portal vein?
A The portal vein is formed by the union of the splenic vein and inferior mesenteric vein posterior to the neck of the pancreas
B The portal vein is formed by the union of the splenic vein and the superior mesenteric vein at the L3 level
C The portal vein receives tributaries including the right and left gastric veins and para-umbilical veins
D The portal vein passes anterior to the superior part of the duodenum to enter the right edge of the lesser omentum
E The portal vein passes anteriorly to the bile duct and hepatic artery proper
ANSWER: C The portal vein receives tributaries including the right and left gastric veins and para-umbilical veins
This is correct, and the portal vein also receives cystic veins from the gall-bladder. The portal vein is formed by the union of the splenic vein and superior mesenteric veins posterior to the neck of the pancreas. It runs along with the hepatic artery proper and common bile duct to form the three components of the portal triad. The hepatoduodenal ligament is a double form the three components of the portal triad. The hepatoduodenal ligament is a double layer of peritoneum - the free edge of the lesser omentum - that encompasses the triad.
This is clinically relevant in liver surgery where the hepatoduodenal ligament may be clamped with a large atraumatic haemostat to halt blood flow and control bleeding from the liver. This is known as the Pringle manoeuvre. Although the portal vein forms posterior to the neck of the pancreas, it is formed by the union of the splenic vein and the superior mesenteric vein. The portal vein is formed at the L1 level.
The portal vein passes posterior to the superior part of the duodenum but does enter the right edge of the lesser omentum. The portal vein passes posteriorly to both these structures.
You are a Foundation Year 2 (FY2) student working in general surgery and are called to a patient with known diverticular disease who now presents with guarding and rebound. A computed tomography (CT) scan confirms a perforation and you later assist in an emergency Hartmann’s procedure. The consultant asks about the features of the small bowel. Which one of these is anatomical features is most associated with the small bowel?
A Omental appendices
B Taeniae coli
C Haustra
D Peritoneal - covered fatty tags
E Valvulae conniventes
ANSWER: E Valvulae conniventes
Valvulae conniventes, also known as plicae circulares, are thin circular mucosal folds in the small bowel. These structures give the small bowel the distinct radiological appearances of lines appearing to pass across the full width of the lumen. Omental appendices are peritoneal-covered fatty accumulations associated with the large bowel. The longitudinal muscles of the large bowel are segregated into three bands, which are known as the taeniae coli. The large bowel’s circular muscles form sacculations known as haustra. Peritoneal - covered fatty tags are most evident in the large bowel and are known as omental appendices.
ou are working in the Urology Department and have been referred a patient with severe Loin to groin pain and haematuria. His pain only settles with intravenous opioid analgesia. You request a computed tomography scan of kidneys, ureters and bladder (CTKUB), which shows an obstructing renal calculus. Which one of these is most likely to be the location of the obstruction?
A The ureteropelvic junction
B The ureteral crossing of the iliac vessels
C The ureterovesical junction
D The ureteral crossing of the renal veins
E The prostatic urethra
ANSWER: C The ureterovesical junction
This is the point at which the ureters enter the wall of the bladder, and is a site of ureterall constriction at which renal stones may lodge. It is the most common site of impaction as it has the smallest diameter of the options listed. Generally for a stone to impact it must have a diameter of 2 mm or greater.
Ureteropelvic junction is the point at which the renal pelvis becomes continues with the ureter and is the first point of constriction at which renal stones can become lodged. Ureteral crossing of the iliac vessels, at the point at which the ureters cross the common iliac vessels the ureters are slightly constricted. Stones lodged here are more unusual than stones lodged at the ureteropelvic or ureterovesical junction.
The ureters do not cross the renal veins. The prostatic urethra is the widest part of the urethra, so an unlikely site for obstruction.
