FRCS Applied Surgical Anatomy — Questions and Answers
Question 1: During an inguinal hernia repair, which structure forms the floor of the inguinal canal?
- External oblique aponeurosis
- Internal oblique muscle
- Transversalis fascia and conjoint tendon (Correct answer)
- Inguinal ligament
Correct answer: Transversalis fascia and conjoint tendon
The floor of the inguinal canal is formed by the transversalis fascia medially and the inguinal (Poupart's) ligament laterally. The roof is formed by arching fibres of the internal oblique and transversalis muscles. Knowing these layers is essential during hernia repair to identify defects and place mesh correctly.
Question 2: The femoral canal lies in which relationship to the femoral vein?
- Lateral
- Anterior
- Medial (Correct answer)
- Posterior
Correct answer: Medial
The femoral canal lies medial to the femoral vein within the femoral sheath. The mnemonic NAVY (from lateral to medial: Nerve, Artery, Vein, Y-fronts/lymphatics) describes the contents of the femoral triangle. Femoral hernias exit through the femoral ring at the medial most compartment.
Question 3: During a right hemicolectomy, which structure must be identified to avoid injury when ligating the ileocolic vessels?
- Right ureter (Correct answer)
- Common iliac artery
- Inferior mesenteric artery
- Hepatic flexure of colon
Correct answer: Right ureter
The right ureter courses over the right iliac vessels, in close proximity to the ileocolic vessels and root of the mesentery. Failure to identify and protect the ureter during right hemicolectomy risks ureteric injury, a recognised and serious complication.
Question 4: What is the blood supply to the spleen?
- Left gastric artery
- Splenic artery from the coeliac trunk (Correct answer)
- Left gastroepiploic artery alone
- Superior mesenteric artery
Correct answer: Splenic artery from the coeliac trunk
The spleen is supplied by the splenic artery, the largest branch of the coeliac trunk. The splenic artery has a tortuous course along the upper border of the pancreas before entering the splenic hilum. Short gastric arteries (from the splenic artery) also supply the fundus of the stomach.
Question 5: The recurrent laryngeal nerve is at risk during thyroidectomy. On which side is a non-recurrent laryngeal nerve most likely to occur?
- Left side
- Right side (Correct answer)
- Either side equally
- Bilateral in 5% of cases
Correct answer: Right side
A non-recurrent laryngeal nerve (NRLN) occurs almost exclusively on the right side (0.5–1% of cases) and is associated with an aberrant right subclavian artery (arteria lusoria). On the right, the NRLN runs directly from the vagus to the larynx without descending into the chest, making it vulnerable to unexpected injury.
Question 6: During a low anterior resection, which autonomic nerve complex must be preserved to maintain urinary and sexual function?
- Hypogastric nerves only
- Inferior hypogastric plexus (pelvic plexus) and hypogastric nerves (Correct answer)
- Pudendal nerve only
- Obturator nerve
Correct answer: Inferior hypogastric plexus (pelvic plexus) and hypogastric nerves
The hypogastric nerves (sympathetic) and pelvic splanchnic nerves (parasympathetic, S2–S4) converge to form the inferior hypogastric plexus (pelvic plexus), which lies on the lateral pelvic wall. These nerves control bladder storage and emptying, and male sexual function. Their injury during TME causes bladder and sexual dysfunction.
FRCS Applied Surgical Anatomy
During an inguinal hernia repair, which structure forms the floor of the inguinal canal?