Chapter: Abdomen; Topic: Inguinal Canal; Subtopic: Superficial Inguinal Ring
Keyword Definitions:
Inguinal Canal: A short oblique passage in the lower anterior abdominal wall, transmitting the spermatic cord in males and the round ligament in females.
Superficial Inguinal Ring: A triangular defect in the external oblique aponeurosis, forming the exit of the inguinal canal.
Aponeurosis: A flat, broad tendon that serves as a connective tissue attachment for muscles.
External Oblique Muscle: The largest and outermost muscle of the abdominal wall, contributing to trunk rotation and compression of abdominal contents.
Lead Question (2015): Superficial inguinal ring is a defect in the:
a) Internal oblique aponeurosis
b) External oblique aponeurosis
c) Transverse abdominis aponeurosis
d) Internal oblique muscle
Explanation: The superficial inguinal ring is an opening in the external oblique aponeurosis, forming the exit of the inguinal canal. It transmits the spermatic cord in males and the round ligament in females. The ring is bounded by medial and lateral crura of the external oblique aponeurosis. Answer: (b)
1. The deep inguinal ring is an opening in which structure?
a) External oblique aponeurosis
b) Transversalis fascia
c) Internal oblique aponeurosis
d) Linea alba
The deep inguinal ring is an opening in the transversalis fascia. It serves as the entrance to the inguinal canal and allows passage of the spermatic cord or round ligament. Its position is above the midpoint of the inguinal ligament. Answer: (b)
2. Which of the following forms the posterior wall of the inguinal canal?
a) External oblique aponeurosis
b) Transversalis fascia
c) Internal oblique muscle
d) Inguinal ligament
The posterior wall of the inguinal canal is mainly formed by the transversalis fascia, with reinforcement from the conjoint tendon medially. This wall provides strength and prevents herniation. Answer: (b)
3. The conjoint tendon is formed by the fusion of aponeuroses of:
a) External and internal oblique
b) Internal oblique and transversus abdominis
c) Transversus abdominis and rectus abdominis
d) Rectus abdominis and external oblique
The conjoint tendon is formed by the lower fibers of the internal oblique and transversus abdominis aponeuroses. It strengthens the posterior wall of the inguinal canal and supports the superficial ring area. Answer: (b)
4. In a male patient, an indirect inguinal hernia passes through which structures?
a) Only superficial ring
b) Both deep and superficial rings
c) Only deep ring
d) Femoral canal
An indirect inguinal hernia enters through the deep inguinal ring, traverses the canal, and emerges from the superficial inguinal ring. It often extends into the scrotum and is congenital due to a patent processus vaginalis. Answer: (b)
5. Inguinal canal in females transmits:
a) Round ligament of uterus
b) Ureter
c) Ovarian artery
d) Inferior epigastric vessels
In females, the inguinal canal transmits the round ligament of the uterus, a remnant of the gubernaculum. It helps maintain uterine anteversion and exits through the superficial ring, ending in the labia majora. Answer: (a)
6. A 45-year-old man presents with a swelling that increases on coughing and reduces on lying down. The hernia passes through both deep and superficial rings. Identify the type.
a) Direct inguinal hernia
b) Indirect inguinal hernia
c) Femoral hernia
d) Umbilical hernia
The described hernia passes through both deep and superficial rings, typical of an indirect inguinal hernia. It follows the embryological path of the testis and may reach the scrotum. The swelling reduces when supine. Answer: (b)
7. A patient with a direct inguinal hernia typically has a defect in:
a) Hesselbach’s triangle
b) Femoral canal
c) Deep ring
d) Pectineal ligament
A direct inguinal hernia occurs through Hesselbach’s triangle, an area bounded by the lateral edge of rectus abdominis, inferior epigastric vessels, and inguinal ligament. It protrudes directly through the posterior wall and does not pass through the deep ring. Answer: (a)
8. A surgeon repairing an inguinal hernia must take care not to injure which nerve lying near the superficial ring?
a) Genitofemoral nerve
b) Ilioinguinal nerve
c) Femoral nerve
d) Obturator nerve
The ilioinguinal nerve runs along the inguinal canal and exits through the superficial ring. During hernia repair, this nerve must be preserved to prevent sensory loss over the upper medial thigh and anterior scrotum or labia majora. Answer: (b)
9. A newborn male has a swelling in the scrotum due to a patent processus vaginalis. The condition is called:
a) Hydrocele
b) Indirect inguinal hernia
c) Cryptorchidism
d) Varicocele
A patent processus vaginalis in newborns can cause an indirect inguinal hernia or a communicating hydrocele. In this case, intestinal loops may herniate through the canal into the scrotum. Answer: (b)
10. A 60-year-old male develops a bulge above the medial part of the inguinal ligament. The hernia does not enter the scrotum. Identify the likely type.
a) Direct inguinal hernia
b) Indirect inguinal hernia
c) Femoral hernia
d) Umbilical hernia
This hernia protrudes directly through the posterior wall of the inguinal canal within Hesselbach’s triangle, not passing through the deep ring. It typically occurs in older males due to abdominal wall weakness. Answer: (a)
Keyword Definitions
Anterior abdominal wall: multilayered structure formed by skin, fascia, muscles, vessels, and nerves protecting abdominal viscera.
External oblique: outermost flat abdominal muscle with fibers directed inferomedially.
Internal oblique: middle layer muscle with fibers running superomedially.
Transversus abdominis: innermost flat muscle, fibers run horizontally.
Rectus abdominis: paired vertical strap muscle enclosed in rectus sheath.
Neurovascular plane: potential space where segmental nerves and vessels run between muscle layers.
Segmental nerves: lower intercostal, subcostal, iliohypogastric, and ilioinguinal nerves supplying wall and skin.
Arcuate line: point below umbilicus where posterior rectus sheath ends; important in surgical incisions.
Linea alba: midline fibrous raphe formed by fusion of aponeuroses.
Transversalis fascia: fascia deep to transversus abdominis, continuous with extraperitoneal fat and peritoneum.
Chapter: Anatomy
Topic: Abdominal Wall
Subtopic: Neurovascular Plane
Lead Question – 2012
Neurovascular plane in anterior abdominal wall -
a) Between ext oblique and internal oblique
b) Between int. oblique and transversus abdominis
c) Below transversus abdominis
d) Above ext. oblique
Explanation: The neurovascular plane of the anterior abdominal wall lies between the internal oblique and transversus abdominis. Intercostal, subcostal, iliohypogastric, and ilioinguinal nerves course here with vessels, making this the safe plane for surgical splitting incisions. Correct answer: (b).
A surgeon makes a gridiron incision for appendectomy. Which muscular plane is split to access the appendix safely?
a) Between external oblique and internal oblique
b) Between internal oblique and transversus abdominis
c) Between rectus and transversalis fascia
d) Below peritoneum
Explanation: The gridiron incision exploits the neurovascular plane between internal oblique and transversus abdominis. This minimizes vascular injury, preserves nerves, and provides safe access. Correct answer: (b).
During laparotomy, injury to iliohypogastric nerve leads to which deficit?
a) Sensory loss over umbilicus
b) Weakness of external oblique
c) Numbness over suprapubic skin
d) Loss of cremaster reflex
Explanation: The iliohypogastric nerve (L1) runs in the neurovascular plane, supplying suprapubic skin. Injury causes sensory loss over suprapubic region. Correct answer: (c).
A patient undergoing lower abdominal surgery develops numbness in scrotum and medial thigh. Which nerve likely injured in the neurovascular plane?
a) Ilioinguinal nerve
b) Genitofemoral nerve
c) Obturator nerve
d) Lateral femoral cutaneous nerve
Explanation: The ilioinguinal nerve travels in the neurovascular plane and enters inguinal canal. Injury produces scrotal/labial and medial thigh numbness. Correct answer: (a).
Which muscle’s aponeurosis contributes to both anterior and posterior layers of rectus sheath above arcuate line?
a) External oblique
b) Internal oblique
c) Transversus abdominis
d) Pyramidalis
Explanation: Internal oblique aponeurosis splits to enclose rectus above arcuate line, forming both anterior and posterior sheath layers. Correct answer: (b).
Below arcuate line, which layer lies posterior to rectus abdominis?
a) External oblique aponeurosis
b) Internal oblique aponeurosis
c) Transversalis fascia
d) Posterior rectus sheath
Explanation: Below arcuate line, all aponeuroses pass anteriorly; only transversalis fascia remains posterior to rectus. Correct answer: (c).
During open hernia repair, which nerve is at risk near superficial inguinal ring?
a) Ilioinguinal nerve
b) Iliohypogastric nerve
c) Genitofemoral nerve
d) Femoral branch of genitofemoral
Explanation: The ilioinguinal nerve emerges from neurovascular plane and runs in inguinal canal, exiting superficial ring. Injury during hernia surgery causes scrotal/labial numbness. Correct answer: (a).
During Pfannenstiel incision, which vessel is at risk in neurovascular plane near lateral rectus?
a) Superior epigastric artery
b) Inferior epigastric artery
c) Deep circumflex iliac artery
d) External iliac vein
Explanation: The inferior epigastric artery runs in rectus sheath lateral border and is vulnerable in lower transverse incisions. Correct answer: (b).
A patient with penetrating trauma to abdominal wall has paralysis of lower rectus abdominis. Which nerve injured?
a) Intercostal T6
b) Intercostal T10
c) Subcostal T12
d) Iliohypogastric L1
Explanation: Rectus abdominis receives segmental innervation from T7–T12 nerves traveling in neurovascular plane. Paralysis of lower rectus implies injury to subcostal T12. Correct answer: (c).
Which landmark guides safe splitting of abdominal wall muscles during laparotomy?
a) Linea alba
b) Neurovascular plane between internal oblique and transversus abdominis
c) Transversalis fascia
d) Median umbilical ligament
Explanation: Muscle splitting incisions like McBurney’s rely on neurovascular plane between internal oblique and transversus abdominis to reduce bleeding and nerve injury. Correct answer: (b).
A 40-year-old male develops flank bulge after nephrectomy incision. Cause?
a) Damage to iliohypogastric/ilioinguinal nerves in neurovascular plane
b) Weakness of transversalis fascia
c) Injury to femoral nerve
d) Loss of rectus sheath integrity
Explanation: Flank bulge results from denervation of internal oblique and transversus due to iliohypogastric/ilioinguinal nerve injury in neurovascular plane during flank incision. Correct answer: (a).