33

Surgical, Radiographic, and

Endoscopic Anatomy of the

Retroperitoneum

Drew A. Palmer; Alireza Moinzadeh

Questions

1.Which of the following structures is NOT in the retroperitoneum?

a.Kidney

b.Second portion of the duodenum

c.Ascending colon

d.Adrenal

e.Transverse colon

2.Which muscle's function is most similar to psoas major?

a.Iliacus

b.Quadratus lumborum

c.Transversus abdominis

d.External oblique

e.Vastus lateralis

3.Which fascial layer is immediately deep to the transversus abdominis muscle?

a.Lumbodorsal fascia

b.Lateroconal fascia

c.Internal oblique fascia

d.External oblique fascia

e.Transversalis fascia

4.A 28-year-old urology resident is injured in a motorcycle accident and suffers Grade 2 renal trauma. The hematoma would most likely continue in which direction:

a.Superior

b.Lateral

c.Medial

d.Caudal

e.Cephalad

5.The anterior and posterior laminae of Gerota fascia merge laterally to form:

a.transversus abdominis.

b.lumbodorsal fascia.

c.lateral renal fascia.

d.lateroconal fascia.

e.perirenal fascia.

6.The blood supply to the adrenal gland may include branches from the:

a.inferior phrenic artery.

b.aorta.

c.renal artery.

d.a and b.

e.a and c.

f.a, b, and c.

7.Which of the following statements is TRUE?

a.The superior mesenteric artery (SMA) may be sacrificed without causing bowel ischemia.

b.Ligation of the inferior mesenteric artery (IMA) will cause ischemia to the large bowel but not the small bowel.

c.The IMA may be sacrificed without colonic ischemia because of collateral circulation via the marginal artery and hemorrhoidal arteries.

d.The IMA may be sacrificed without colonic ischemia because of collateral circulation via the ileocolic artery.

e.Neither the superior nor the inferior mesenteric arteries may be sacrificed without causing bowel ischemia.

8.Which of the following statements is FALSE?

a.The right testicular vein typically drains into the inferior vena cava (IVC).

b.The left testicular vein typically drains into the left renal vein.

c.Unilateral varicoceles are more common on the left side.

d.A sudden onset unilateral right-sided varicocele should prompt retroperitoneal imaging.

e.The left ovarian vein typically drains into the IVC.

9.What statement best describes the lymphatic drainage of the right testis?

a.Superficial then deep right inguinal nodes

b.Left para-aortic with some drainage to the interaortocaval nodes

c.Only to the interaortocaval nodes

d.Primarily to the interaortocaval nodes with some drainage to the right paracaval nodes

e.Interaortocaval nodes primarily with some drainage to the right

paracaval nodes and a small but appreciable amount of drainage to the left para-aortic nodes

.What is the major function of the muscles innervated by the obturator nerve?

a.Hip adduction

b.Hip abduction

c.Hip flexion

d.Hip extension

e.Knee flexion

Answers

1.e. Transverse colon. The contents of the retroperitoneum include the kidneys, ureters, adrenals, pancreas, second and third portions of the duodenum, ascending colon, descending colon, arterial structures including the aorta and its branches, venous structures including the inferior vena cava and its tributaries, lymphatics, lymph nodes, sympathetic trunk, and lumbosacral plexus. The transverse colon is intraperitoneal.

2.a. Iliacus. Psoas major functions in flexion of the thigh at the hip joint and is innervated by the anterior rami of L1, L2, and L3. Iliacus is the only muscle listed that also functions in flexion of the thigh at the hip joint.

3.e. Transversalis fascia. The transversalis fascia lies deep to the transversus abdominis muscle and superficial to the preperitoneal fat and peritoneum.

4.d. Caudal. The perirenal space around the kidney is cone-shaped and is open at its inferior extent in the extraperitoneal pelvis. If a hematoma were to form within the Gerota fascia, it would be able to travel in a caudal direction.

5.d. Lateroconal fascia. The anterior and posterior laminae of Gerota fascia merge laterally to form the lateroconal fascia, which functions to separate the anterior and posterior pararenal spaces. It can be visualized radiographically on computed tomographic (CT) scan and continues anterolaterally deep to the

transversalis fascia.

6.f. a, b, and c. The adrenal gland may receive branches from the superior adrenal artery off of the inferior phrenic artery, the middle adrenal artery off of the aorta, and the inferior adrenal artery off of the renal artery.

7.c. The IMA may be sacrificed without colonic ischemia because of collateral circulation via the marginal artery and hemorrhoidal arteries.

The SMA supplies the pancreas (inferior pancreaticoduodenal artery), small intestine, and the majority of the large intestine (ileocolic, right colic, and middle colic). Ligation of the SMA will result in catastrophic bowel ischemia (without pancreatic ischemia because of collaterals from the celiac artery and the superior pancreaticoduodenal artery). The branches of the IMA are the left colic, sigmoid, and superior hemorrhoidal (rectal) arteries. The collateral circulation of the sigmoid artery via the marginal artery of Drummond and the inferior and middle hemorrhoidal arteries allows for the IMA to be sacrificed without colonic ischemia.

8.e. The left ovarian vein typically drains into the IVC. The venous drainage of the ovarian and testicular veins is similar. The right testicular and the right ovarian veins typically drain into the IVC while the left testicular and the left ovarian veins drain into the left renal vein. Unilateral varicoceles are more common on the left, which may be a result of the increased length and perpendicular entry of the left testicular vein into the left renal vein. Given the rarity of unilateral right-side varicocele, a sudden-onset right-side varicocele should increase suspicion for a renal or retroperitoneal malignancy leading to poor outflow and warrants retroperitoneal imaging.

9.e. Interaortocaval nodes primarily with some drainage to the right paracaval nodes and a small but appreciable amount of drainage to the

left para-aortic nodes. The right testis drains primarily to the interaortocaval nodes with some drainage to the right paracaval nodes. The left para-aortic region does receive a small but appreciable amount of lymphatic drainage from the right testis. This drainage pattern is consistent with the global lymphatic flow from right to left.

.a. Hip adduction. The obturator nerve innervates the muscles of the medial thigh compartment. These include the gracilis, adductor longus, adductor brevis, adductor magnus, and obturator externus muscles. The muscles function to adduct and rotate the thigh at the hip joint.

Table 33-1

Branches of the Abdominal Aorta

Modified from Drake RL, Vogl W, Mitchell AWM. Gray's anatomy for students. Philadelphia: Elsevier; 2005. p. 331.

Table 33-2

Branches of the Lumbosacral Plexus

Modified from Drake RL, Vogl W, Mitchell AWM. Gray's anatomy for students. Philadelphia: Elsevier; 2005. p. 340.

Chapter review

1.The upper pole of the left kidney is located at the level of the 11th rib. The upper pole of the right kidney is located at the level of the 12th rib.

2.The tail of the pancreas lies in close proximity to the upper pole of the

left kidney and left adrenal gland.

3.The superior arterial supply to the adrenal is from the phrenic artery and is constant; the middle and inferior arteries are variable.

4.The main renal vein courses ventral to the artery.

5.Lumbar veins often drain into the left renal vein and sometimes into the right renal vein and may be injured when dissecting the renal vein.

6.The general direction of lymph flow is from caudal to cephalad and right to left.

7.The perirenal space around the kidney is cone-shaped and is open at its inferior aspect in the extraperitoneal pelvis.

8.The IMA may be sacrificed without colonic ischemia because of collateral circulation via the marginal artery and hemorrhoidal arteries.

9.Ligation of the SMA will result in catastrophic bowel ischemia.

10.The venous drainage of the ovarian and testicular veins is similar. The right testicular and the right ovarian veins typically drain into the IVC, whereas the left testicular and the left ovarian veins drain into the left renal vein.

11.Unilateral varicoceles are more common on the left, which may be a result of the increased length and perpendicular entry of the left testicular vein into the left renal vein. Given the rarity of unilateral rightside varicocele, a sudden-onset right-side varicocele should increase suspicion for a renal or retroperitoneal malignancy.