CSFA Surgical Anatomy and Physiology 4 — Questions and Answers
Question 1: Which retroperitoneal structure crosses the pelvic brim at the bifurcation of the iliac vessels and is at risk during pelvic surgery?
- Femoral nerve
- Obturator nerve
- Ureter (Correct answer)
- Ilioinguinal nerve
Correct answer: Ureter
The ureter crosses the pelvic brim at the bifurcation of the common iliac artery, making it vulnerable during pelvic dissections such as hysterectomy and colorectal resections.
Question 2: The angle of Louis (sternal angle) is a reliable surface landmark for identifying which anatomic structure?
- First rib articulation
- Carina and bifurcation of the trachea (Correct answer)
- Aortic valve projection
- Xiphoid process
Correct answer: Carina and bifurcation of the trachea
The sternal angle corresponds to the T4–T5 vertebral level, marking the carina where the trachea bifurcates into the main bronchi.
Question 3: During a femoral hernia repair, which structure forms the medial boundary of the femoral ring?
- Femoral vein
- Iliopubic tract
- Lacunar (Gimbernat's) ligament (Correct answer)
- Inguinal ligament
Correct answer: Lacunar (Gimbernat's) ligament
The lacunar ligament forms the sharp medial boundary of the femoral ring and must be carefully divided to reduce an incarcerated femoral hernia.
Question 4: Which physiologic response describes the shift of the oxyhemoglobin dissociation curve to the right, favoring oxygen release to tissues?
- Bohr effect caused by increased pH and decreased CO2
- Bohr effect caused by decreased pH, increased CO2, and increased 2,3-DPG (Correct answer)
- Haldane effect
- Left shift due to hypothermia
Correct answer: Bohr effect caused by decreased pH, increased CO2, and increased 2,3-DPG
Decreased pH, increased PCO2, elevated temperature, and increased 2,3-DPG all shift the curve rightward (Bohr effect), lowering hemoglobin's affinity for O2 and promoting release to metabolically active tissues.
Question 5: The obturator nerve (L2–L4) exits the pelvis through the obturator foramen and primarily innervates which muscle group?
- Hip flexors
- Medial thigh adductors (Correct answer)
- Knee extensors
- Foot dorsiflexors
Correct answer: Medial thigh adductors
The obturator nerve innervates the medial compartment adductor muscles of the thigh including adductor longus, brevis, magnus, and gracilis.
Question 6: Which hepatic segment, according to the Couinaud classification, is located posteriorly and is accessible only via a posterior approach or right hepatectomy?
- Segment I (caudate lobe)
- Segment VI
- Segment VII (Correct answer)
- Segment VIII
Correct answer: Segment VII
Couinaud segment VII is located in the posterosuperior right lobe and is among the most challenging to access, often requiring a posterior or laparoscopic approach.
Question 7: In renal physiology relevant to surgical fluid management, the loop of Henle's descending limb is permeable to:
- Sodium and chloride but not water
- Water only (Correct answer)
- Urea only
- Sodium, water, and urea equally
Correct answer: Water only
The descending limb of the loop of Henle is permeable to water but not to solutes, concentrating the tubular fluid as it descends into the hypertonic medulla.
CSFA Surgical Anatomy and Physiology 4
Which retroperitoneal structure crosses the pelvic brim at the bifurcation of the iliac vessels and is at risk during pelvic surgery?