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Xiphoid process: Marks lower end of the sternum and upper limit of anterior abdominal wall.
Costal margin: Lower border of thoracic cage formed by 7th–10th costal cartilages.
Umbilicus: Midline depression representing site of umbilical cord attachment; level of disc between L3 and L4 vertebrae in adults.
Linea alba: Fibrous midline extending from xiphoid process to pubic symphysis.
Linea semilunaris: Curved line marking lateral border of rectus abdominis.
Pubic tubercle: Bony prominence 2.5 cm lateral to midline; attachment of inguinal ligament.
Anterior superior iliac spine (ASIS): Palpable bony point marking lateral end of inguinal ligament.
Tendinous intersections of rectus abdominis: Three transverse ridges seen on front of the abdomen—
One opposite the xiphoid process
One opposite the umbilicus
One midway between them
Highly elastic; capable of marked stretching during pregnancy, obesity, or ascites.
Overstretching causes lineae albicantes (striae)—whitish streaks in lower abdominal skin due to tearing of dermal collagen.
Skin near umbilicus is innervated by T10 segment of spinal cord.
Consists of two layers:
Fatty layer (Camper’s fascia) — contains variable fat.
Membranous layer (Scarpa’s fascia) — thin, fibrous layer deep to the fatty one.
Continuity:
Camper’s layer continues into thigh and perineum.
Scarpa’s layer continues as Colles’ fascia in perineum.
Attachments:
Fused to pubic arch and posterior margin of perineal membrane.
Clinical importance:
Urine from a ruptured urethra may collect beneath Scarpa’s fascia and spread into the lower abdominal wall.
Incision lines:
Vertical incision from xiphoid process → umbilicus → pubic symphysis.
Circular incision around umbilicus and curved incisions from ASIS → pubic symphysis on both sides.
Additional oblique incision along costal margin laterally.
Reflection:
Reflect skin in four flaps, keeping both fascia layers intact.
Identification:
Expose fatty and membranous layers.
Observe continuity of membranous layer with Colles’ fascia.
Identify superficial inguinal ring superolateral to pubic tubercle.
Locate anterior cutaneous branch of iliohypogastric nerve piercing external oblique aponeurosis.
Find spermatic cord or round ligament and ilioinguinal nerve emerging through superficial inguinal ring.
Cutaneous nerves and vessels:
Observe anterior and lateral cutaneous branches of lower intercostal nerves and accompanying vessels emerging through the wall.
Summary:
These landmarks and dissections are essential for understanding abdominal wall layers, inguinal anatomy, and surgical approaches to hernia repair or drainage.
Definition:
The umbilicus (navel) is a normal scar on the anterior abdominal wall, marking the site where the umbilical cord was attached in the fetus.
Position:
Lies in the midline, at the level of the L3–L4 intervertebral disc in adults.
Lies lower in infants and in individuals with pendulous abdomens.
Anatomical importance:
Acts as a watershed line for lymphatic and venous drainage:
Above umbilicus → drains upwards to axillary nodes and thoracoepigastric veins.
Below umbilicus → drains downwards to superficial inguinal nodes and superficial epigastric veins.
The skin around umbilicus is supplied by T10 spinal segment.
Serves as an important surgical landmark—used in laparoscopic and open abdominal procedures.
Umbilical hernia:
Protrusion of peritoneum and abdominal contents through a weak umbilical ring, commonly seen in infants.
Paraumbilical hernia:
Herniation through the linea alba near the umbilicus, seen in adults (especially multiparous women).
Umbilical fistula:
Persistence of vitellointestinal duct → discharge of intestinal contents through umbilicus.
Urachal fistula/cyst/sinus:
Persistence of allantoic canal (urachus) connecting bladder to umbilicus → urine discharge or midline swelling.
Sister Mary Joseph nodule:
Secondary cancerous deposit at umbilicus, usually from intra-abdominal malignancy (gastric or ovarian).
Layers:
Camper’s fascia (fatty layer):
Contains variable fat, more abundant below umbilicus and after puberty.
Continuous with superficial fascia of thigh and perineum.
Scarpa’s fascia (membranous layer):
Lies deep to the fatty layer.
Attached to pubic arch and posterior border of perineal membrane.
Continues into the perineum as Colles’ fascia.
Contents:
Fat (variable in amount)
Cutaneous nerves and vessels
Superficial lymphatics
Urine extravasation:
If the spongy urethra ruptures, urine spreads under Scarpa’s fascia → extends into lower abdominal wall, scrotum, and perineum, but not into thigh (due to fascia attachment to inguinal ligament).
Derived mainly from T7–T12 (thoracoabdominal nerves) and L1 (iliohypogastric and ilioinguinal).
Distribution:
Anterior cutaneous branches:
T7 near xiphoid process.
T10 at umbilicus.
L1 (iliohypogastric) about 2.5 cm above superficial inguinal ring.
Lateral cutaneous branches:
From T10–T11; supply flanks of abdomen.
Branches of T12 (subcostal) and L1 supply the anterosuperior gluteal region.
Functions:
Provide segmental sensory supply to skin.
Also carry motor fibres to muscles and sympathetic fibres to blood vessels and sweat glands.
Superficial epigastric artery: Branch of femoral artery; runs upward to supply skin below umbilicus.
Superficial circumflex iliac artery: Branch of femoral artery; runs laterally toward ASIS.
Superficial external pudendal artery: Supplies skin of pubic region and external genitalia.
Superior epigastric artery: Continuation of internal thoracic artery; supplies skin and muscle above umbilicus.
Inferior epigastric artery: From external iliac artery; ascends behind rectus abdominis.
Above umbilicus: Drain upward into thoracoepigastric and lateral thoracic veins → axillary vein.
Below umbilicus: Drain downward into superficial epigastric and superficial external pudendal veins → femoral vein.
Deep veins: Accompany arteries and ultimately drain into internal thoracic or external iliac veins.
Paraumbilical veins: Connect superficial veins with portal vein via ligamentum teres hepatis.
Caput Medusae:
Dilated, tortuous veins radiating from the umbilicus due to portal hypertension and reopening of paraumbilical veins.
Caval–portal anastomosis:
The umbilical region is one of the major sites where systemic (caval) and portal venous systems communicate.
Superficial epigastric veins:
Provide a route for collateral venous return when the inferior vena cava is obstructed.
The three flat muscles—external oblique, internal oblique, and transversus abdominis—form the anterolateral wall, while rectus abdominis (vertical) lies medially.
Together, they provide strength, maintain intra-abdominal pressure, and assist in trunk movement.
Origin:
Outer surfaces of the lower eight ribs (5th–12th).
Upper slips interdigitate with serratus anterior; lower slips with latissimus dorsi.
Insertion:
Aponeurosis inserts into xiphoid process, linea alba, pubic crest, and pectineal line.
Inferior margin forms the inguinal ligament (from ASIS to pubic tubercle).
Nerve Supply:
Lower six thoracic nerves + first lumbar nerve.
Special Features:
Aponeurosis contributes to the anterior wall of the rectus sheath.
Forms inguinal ligament, lacunar ligament, and superficial inguinal ring.
Dissection Notes:
Identify origins on eight ribs; note interdigitations.
Cut vertically down to the iliac crest (behind sixth digitation) and reflect muscle.
Expose the underlying internal oblique.
Avoid injuring lateral cutaneous branches of subcostal and iliohypogastric nerves near iliac crest.
Origin:
Lateral two-thirds of inguinal ligament,
Anterior two-thirds of iliac crest,
Thoracolumbar fascia.
Insertion:
Inferior border of lower three or four costal cartilages,
Aponeurosis to linea alba, pubic crest, and pectineal line.
Nerve Supply:
Lower six thoracic nerves and first lumbar nerve (iliohypogastric and ilioinguinal).
Other Points of Interest:
Aponeurosis splits around rectus abdominis above arcuate line (anterior and posterior laminae).
Below arcuate line, aponeurosis passes entirely in front of rectus abdominis.
Contributes to conjoint tendon and cremaster muscle.
Dissection Steps:
Lift internal oblique; cut attachments from inguinal ligament, iliac crest, and costal margin.
Reflect forwards, preserving nerves between internal oblique and transversus abdominis (neurovascular plane).
Origin:
Lateral ⅓ of inguinal ligament
Inner lip of iliac crest (anterior ⅔)
Thoracolumbar fascia
Inner surfaces of lower six costal cartilages
Insertion:
Aponeurosis to xiphoid process, linea alba, pubic crest, and pectineal line.
Lower fibres fuse with internal oblique to form the conjoint tendon.
Nerve Supply:
Lower six thoracic nerves + first lumbar nerve.
Special Features:
Aponeurosis forms posterior wall of rectus sheath above arcuate line and anterior wall below it.
Neurovascular plane lies between internal oblique and transversus abdominis, transmitting major segmental nerves and vessels.
Dissection Notes:
Reflect internal oblique to expose transversus.
Identify its horizontal fibres and aponeurosis forming the posterior rectus sheath.
Take care not to injure intercostal and lumbar nerves running in this plane.
Origin:
From pubic crest and pubic symphysis.
Insertion:
Into 5th, 6th, and 7th costal cartilages and xiphoid process.
Structure:
Long, strap-like muscle on either side of linea alba.
Interrupted by three tendinous intersections—at the xiphoid, umbilicus, and midway between them.
Enclosed in the rectus sheath.
Crossed by arcuate line—marks transition between posterior and anterior wall contribution of aponeuroses.
Nerve Supply:
Lower six thoracic nerves.
Action:
Flexes trunk and vertebral column.
Compresses abdominal contents.
Stabilizes pelvis during walking.
External Oblique: Rotates trunk to opposite side.
Internal Oblique: Rotates trunk to same side.
Transversus Abdominis: Compresses abdominal contents, maintains intra-abdominal pressure.
Rectus Abdominis: Flexes trunk and stabilizes pelvis.
Cremaster: Elevates testis.
Pyramidalis: Tenses linea alba (rudimentary action).
Extent:
From ASIS to pubic tubercle (rolled inferior border of external oblique aponeurosis).
Relations and Attachments:
Upper surface: gives origin to internal oblique (lateral ⅔) and transversus abdominis (lateral ⅓).
Medial half forms floor of inguinal canal; lodges spermatic cord/round ligament.
Extensions:
Lacunar ligament (pectineal part): triangular, attached to pecten pubis; forms medial boundary of femoral ring.
Pectineal ligament (Cooper’s ligament): extension from base of lacunar ligament to pecten pubis.
Reflected part: fibres run upward and medially behind superficial inguinal ring.
Intercrural fibres: reinforce margins of superficial inguinal ring
Volume 2, BD Chaurasia’s Human …
.Formed by fusion of lowest aponeurotic fibres of internal oblique and transversus abdominis.
Attached to pubic crest and pecten pubis.
Strengthens posterior wall of inguinal canal where it is otherwise weak.
Medially continuous with anterior wall of rectus sheath.
Origin:
From middle third of inguinal ligament, pubic tubercle, pubic crest, and conjoint tendon.
Some fibres continuous with internal oblique and transversus muscles.
Insertion:
Forms loops around spermatic cord and testis, creating cremasteric fascia.
Nerve Supply:
Genital branch of genitofemoral nerve (L1).
Action:
Elevates and suspends testis; closes superficial inguinal ring during raised intra-abdominal pressure.
Cremasteric Reflex:
Stroking upper medial thigh causes testicular elevation (via L1 segment).
Reflex absent in upper motor neuron lesion above L1
Volume 2, BD Chaurasia’s Human …
.Structure:
Small, triangular, rudimentary muscle.
Origin: anterior surface of pubis.
Insertion: linea alba.
Nerve Supply: subcostal nerve (T12).
Action: tenses linea alba (minor role)
Volume 2, BD Chaurasia’s Human …
.Expose internal oblique deep to external oblique.
Identify cremaster muscle loops around spermatic cord.
Trace internal oblique fibres to conjoint tendon.
Study intercrural fibres reinforcing superficial inguinal ring
Volume 2, BD Chaurasia’s Human …
.Relaxation technique: Flex knees and hips to relax abdominal muscles during palpation.
Visceroptosis: Drooping of abdominal wall from poor muscle tone.
Abdominal incisions:
Midline (linea alba): bloodless but risk of ventral hernia.
Infraumbilical: safer—recti prevent herniation.
Paramedian: more secure, protects nerves.
Conjoint tendon: prevents direct inguinal hernia; its weakness predisposes to herniation
Represent terminal parts of lower six thoracic nerves — lower five intercostal and subcostal (T7–T12).
They travel between internal oblique and transversus abdominis in the neurovascular plane.
Functions:
Supply abdominal wall muscles.
Provide sensory fibres to overlying skin (through anterior and lateral cutaneous branches).
Maintain abdominal wall tone and check bowing of rectus muscle during contraction.
Continuation of internal thoracic artery.
Enters rectus sheath by passing between costal and xiphoid origins of diaphragm.
Lies behind rectus abdominis, supplies it, and anastomoses with inferior epigastric artery.
Arises from external iliac artery just above the inguinal ligament.
Passes upward and medially, medial to deep inguinal ring.
Pierces fascia transversalis and enters rectus sheath in front of arcuate line.
Supplies rectus abdominis and gives:
Cremasteric branch (spermatic cord/round ligament).
Pubic branch (joins obturator artery; may replace it as abnormal obturator artery).
Muscular and cutaneous branches.
Branch of external iliac artery (lateral to inferior epigastric).
Runs laterally and upward behind inguinal ligament → pierces fascia transversalis → passes along iliac crest between transversus and internal oblique.
Anastomoses near ASIS with superior gluteal, lateral circumflex femoral, and superficial circumflex iliac arteries.
Definition:
An aponeurotic sheath enclosing the rectus abdominis and pyramidalis, formed by aponeuroses of external oblique, internal oblique, and transversus abdominis.
Anterior wall: Complete, adherent to tendinous intersections.
Posterior wall: Incomplete; deficient above costal margin and below arcuate line.
Fusion in midline: Forms linea alba.
Lateral boundary: Linea semilunaris (from 9th costal cartilage to pubic tubercle).
| Region | Anterior Wall | Posterior Wall |
|---|---|---|
| Above costal margin | External oblique aponeurosis | None — rectus lies directly on costal cartilages |
| Between costal margin and arcuate line | External oblique aponeurosis + anterior lamina of internal oblique | Posterior lamina of internal oblique + transversus aponeurosis |
| Below arcuate line | Aponeuroses of all three flat muscles (external, internal, transversus) | Deficient — rectus rests on fascia transversalis |
Contents:
Muscles: Rectus abdominis, pyramidalis (if present).
Arteries: Superior and inferior epigastric arteries.
Veins: Accompanying venae comitantes.
Nerves: Lower intercostal and subcostal nerves.
Each abdominal muscle contributes a bilaminar aponeurosis.
Fibres from all anterior leaves run upwards and medially; posterior leaves run downwards and medially, crossing at right angles.
The linea alba is the central tendon of these decussating aponeuroses — like a common central tendon of a digastric system.
Anterior sheath:
Both leaves of external oblique + anterior leaf of internal oblique.
Posterior sheath:
Posterior leaf of internal oblique + both leaves of transversus aponeurosis.
Deep fibres of linea alba attach behind rectus to posterior pubic crest, superficial fibres to symphysis pubis.
Definition:
Part of the endoabdominal fascia lining the inner surface of transversus abdominis; separated from peritoneum by extraperitoneal connective tissue.
Extent:
Anteriorly: Adherent to linea alba.
Posteriorly: Merges with thoracolumbar fascia → continuous with renal fascia.
Superiorly: Continuous with diaphragmatic fascia.
Inferiorly: Attached to inner lip of iliac crest and lateral half of inguinal ligament → continues as fascia iliaca.
Medially: Attached to pubic tubercle, pubic crest, and pectineal line.
Prolonged into thigh as anterior wall of femoral sheath.
Openings and Relations:
Deep inguinal ring: Oval opening 1.2 cm above mid-inguinal point, lateral to inferior epigastric artery — transmits spermatic cord or round ligament.
Prolongations:
Forms internal spermatic fascia around spermatic cord.
Forms anterior wall of femoral sheath.
Relations to vessels and nerves:
Main arteries lie inside fascia transversalis.
Main nerves lie outside — explaining why femoral vessels are inside femoral sheath, but femoral nerve lies outside.
Identify rectus abdominis and its lateral border.
Observe splitting of internal oblique aponeurosis—anterior part joins external oblique; posterior joins transversus to form sheath.
Locate arcuate line midway between umbilicus and pubic symphysis.
Open sheath vertically, reflect anterior wall, and lift rectus to view superior and inferior epigastric arteries and nerves (T7–T12) entering the sheath.
Observe how posterior wall ends at arcuate line; below it, rectus rests on fascia transversalis
An oblique intermuscular passage in the lower part of the anterior abdominal wall, just above the medial half of the inguinal ligament.
Length: ~ 4 cm
Direction: Downwards, forwards, and medially
Extent: From deep inguinal ring to superficial inguinal ring
Larger in males than females
Anterior wall
Entire length → Skin, superficial fascia, external oblique aponeurosis
Lateral one-third → Fleshy fibres of internal oblique
Posterior wall
Entire length → Fascia transversalis, extraperitoneal tissue, parietal peritoneum
Medial two-thirds → Conjoint tendon and reflected part of inguinal ligament
Roof
Arched fibres of internal oblique and transversus abdominis
Floor
Grooved upper surface of inguinal ligament
Medial end strengthened by lacunar ligament
1. In males: Spermatic cord
2. In females: Round ligament of uterus
Both enter through deep ring and exit via superficial ring
3. Ilioinguinal nerve: Enters between external and internal oblique muscles, exits through superficial ring (outside cord)
Ductus deferens
Arteries: Testicular, cremasteric, and artery of ductus deferens
Pampiniform plexus of veins
Lymphatics from testis
Genital branch of genitofemoral nerve, sympathetic plexus around artery of ductus deferens
Remnants of processus vaginalis
Coverings (from within outwards):
Internal spermatic fascia → from fascia transversalis
Cremasteric fascia → from internal oblique and transversus abdominis
External spermatic fascia → from external oblique aponeurosis
Volume 2, BD Chaurasia’s Human …
Flap-valve mechanism: Obliquity of canal → Anterior and posterior walls approximate on raised intra-abdominal pressure.
Guarding of superficial ring: By conjoint tendon and reflected part of inguinal ligament.
Guarding of deep ring: By internal oblique fibres.
Shutter mechanism: Contraction of internal oblique and transversus → Roof approximates to floor.
Ball-valve mechanism: Cremaster contraction plugs superficial ring.
Slit-valve mechanism: External oblique contraction approximates crura of superficial ring.
Hormonal tone: Maintains muscular integrity.
All these act during coughing, sneezing, or straining, preventing herniation
Volume 2, BD Chaurasia’s Human …
.
Represents the path of gubernaculum through abdominal wall, connecting developing gonad (lumbar region) to labioscrotal swelling.
Canal lengthens as pelvis widens and deep ring shifts laterally.
Unique to humans → prone to hernia due to evolutionary upright posture.
Evolutionary changes:
Iliac crest moved forward → External oblique attached firmly → Loss of dynamic closure by muscle.
Internal oblique and transversus shifted origin from iliopsoas sheath to inguinal ligament → Reduced sphincteric power.
Widened femoral passage → Predisposition to femoral hernia
Volume 2, BD Chaurasia’s Human …
.Identify superficial ring above pubic tubercle (in external oblique aponeurosis).
Locate internal oblique deep to external oblique — note its anterior relation to deep ring.
Expose spermatic cord with coverings and constituents.
Observe the deep ring above mid-inguinal point (lateral to inferior epigastric vessels).
Inguinal hernia: Common due to congenital or acquired weakness in canal.
Direct hernia: Medial to inferior epigastric artery (Hesselbach’s triangle).
Indirect hernia: Lateral to inferior epigastric artery (through deep ring).
Hydrocele: Persistence of processus vaginalis.
Cremasteric reflex loss: Seen in L1 spinal lesions.
Femoral hernia: Through femoral canal, below inguinal ligament — more common in females.
Case:
In a case of intestinal obstruction, an incision has to be made above the umbilicus.
Questions:
Which is the ideal site for the incision?
Should the rectus abdominis muscle be retracted medially or laterally?
Answer:
The ideal site for incision is a paramedian incision.
Although the median incision is relatively bloodless, it often leaves a postoperative weakness, through which a ventral hernia may later develop.
A paramedian incision through the rectus sheath is more secure and preferred.
The rectus abdominis muscle should be retracted laterally, as the thoracic nerves enter the rectus from its lateral side; retracting it medially risks nerve injury and postoperative muscle paralysis
Case:
A male patient presents with a groin swelling that increases on coughing and reduces on lying down.
Question:
How will you differentiate between direct and indirect inguinal hernia?
Answer:
Indirect hernia: Lateral to inferior epigastric artery, passes through deep and superficial rings, may descend into scrotum.
Direct hernia: Medial to inferior epigastric artery, through Hesselbach’s triangle, rarely enters scrotum.
Clinical test: Deep ring occlusion test — if hernia reappears after releasing pressure over deep ring, it’s indirect; if it reappears despite pressure, it’s direct.
Case:
A scrotal swelling transilluminates with a torchlight.
Question:
What is the anatomical basis of this condition?
Answer:
Persistence of the processus vaginalis leads to collection of fluid around the testis → hydrocele.
If the processus remains patent throughout, peritoneal fluid may flow freely between abdomen and scrotum (congenital hydrocele).
In hernia, bowel loops enter canal — non-transilluminant.
Case:
A middle-aged woman presents with a painful swelling below and lateral to the pubic tubercle.
Question:
Why is this more common in females?
Answer:
Femoral canal is wider in females due to broader pelvis and smaller femoral vessels.
Boundaries: lacunar ligament medially, femoral vein laterally, inguinal ligament anteriorly.
Lies below and lateral to pubic tubercle (distinguishes from inguinal hernia).
Prone to strangulation due to rigid femoral ring.
Case:
A postoperative patient develops a bulge near the site of an old abdominal incision.
Answer:
Due to weakness of musculoaponeurotic layer or injury to segmental nerves during previous surgery.
Common after midline incisions; paramedian preferred to prevent recurrence.
Case:
A young male with ureteric colic complains of pain radiating to scrotum and testis.
Question:
Explain the referred pain anatomically.
Answer:
Both ureter and testis share same segmental nerve supply (T10–T12).
Pain from ureteric stone travels via sympathetic afferents → perceived in testis due to common spinal segment.
Case:
A patient with a long-standing inguinal hernia develops severe pain, vomiting, and tender irreducible swelling.
Explanation:
The neck of the hernial sac is narrow; when intestinal loops enter, venous return is obstructed → ischemia → strangulation.
Seen more in indirect hernias because of narrower deep ring.
Case:
An elderly man has recurrent bulging in the groin medial to deep ring.
Explanation:
The conjoint tendon (falx inguinalis) reinforces posterior wall of canal.
Weakness → direct inguinal hernia through Hesselbach’s triangle.
Case:
Reflex absent on right side after spinal injury.
Explanation:
Reflex depends on L1 spinal segment (ilioinguinal sensory + genitofemoral motor).
Loss indicates upper motor neuron lesion above L1.
Case:
Dilated veins radiating from umbilicus seen in a patient with liver cirrhosis.
Explanation:
Due to reopening of paraumbilical veins connecting portal and systemic veins → portal hypertension manifestation.
Case:
A newborn has a soft bulge at the umbilicus.
Explanation:
Weak umbilical scar + raised intra-abdominal pressure during crying.
Common in premature infants; usually closes spontaneously.
Case:
A loop of intestine is strangulated at hernial neck but without obstruction symptoms.
Explanation:
Only the antimesenteric border of bowel is trapped.
Dangerous because strangulation occurs without visible distension.
Case:
A lateral abdominal wall hernia occurs between semilunar line and lateral edge of rectus abdominis.
Explanation:
Weakness in aponeurotic region of transversus abdominis → Spigelian fascia herniation.
Case:
Early pain felt around the umbilicus, later localised to right iliac fossa.
Explanation:
Early visceral pain via T10 (same as umbilical skin).
Later somatic pain when parietal peritoneum involved.
Case:
In a 6-year-old boy, testis not palpable in scrotum.
Explanation:
Cryptorchidism (undescended testis) due to defective gubernacular descent.
Leads to infertility and ↑ risk of malignancy.
Case:
A swelling appears in anterior abdominal wall after multiple pregnancies.
Explanation:
Linea alba stretching and rectus muscle separation (diastasis recti).
Weak fascial support predisposes to ventral hernia.
1. What is the length and direction of the inguinal canal?
It measures about 4 cm, runs downwards, forwards, and medially, just above the medial half of the inguinal ligament.
2. What forms the anterior wall of the inguinal canal?
The external oblique aponeurosis throughout, and internal oblique muscle laterally.
3. What forms the posterior wall of the inguinal canal?
The fascia transversalis throughout, strengthened medially by the conjoint tendon.
4. What are the contents of the inguinal canal in males and females?
Males: Spermatic cord and ilioinguinal nerve.
Females: Round ligament of uterus and ilioinguinal nerve.
5. What are the coverings of the spermatic cord?
(From inside out) — Internal spermatic fascia, cremasteric fascia, and external spermatic fascia.
6. What structures form the roof and floor of the canal?
Roof: Arched fibres of internal oblique and transversus abdominis.
Floor: Inguinal ligament and lacunar ligament medially.
7. What is the role of fascia transversalis in the canal?
It forms the posterior wall and gives rise to the internal spermatic fascia at the deep ring.
8. What is the mechanism preventing herniation?
The oblique course of the canal, shutter, ball-valve, slit-valve, and flap-valve mechanisms act together.
9. What is the difference between direct and indirect inguinal hernias?
Direct: Medial to inferior epigastric artery (Hesselbach’s triangle).
Indirect: Lateral to inferior epigastric artery, through deep ring.
10. What is Hesselbach’s triangle?
Bounded by lateral border of rectus abdominis, inferior epigastric artery, and inguinal ligament — site of direct inguinal hernia.
11. Why is the canal longer and larger in males?
Due to the presence of spermatic cord and descent of the testis through the canal.
12. What is the importance of the ilioinguinal nerve?
It provides sensory innervation to upper scrotum or mons pubis and exits through superficial ring.
13. What is the deep inguinal ring?
An oval opening in fascia transversalis, located ½ inch above the mid-inguinal point.
14. What is the superficial inguinal ring?
A triangular gap in external oblique aponeurosis, above and lateral to pubic crest.
15. What is the clinical significance of the conjoint tendon?
It strengthens the posterior wall; its weakness predisposes to direct hernia.
16. What happens if processus vaginalis fails to obliterate?
Leads to congenital indirect hernia or hydrocele.
17. What is the cremasteric reflex?
Gentle stroking of inner thigh causes elevation of testis due to genitofemoral nerve (L1).
18. What is a femoral hernia?
Protrusion of abdominal contents through femoral ring, below inguinal ligament; more common in females.
19. What are the boundaries of the deep and superficial rings?
Deep ring: Fascia transversalis.
Superficial ring: External oblique aponeurosis.
20. What are the main arterial relations of the canal?
Inferior epigastric artery lies medial to deep ring — landmark in differentiating hernia types.
1. The skin around the umbilicus is innervated by one of the following thoracic segments:
a. T8 b. T9 c. T10 d. T11
2. Which of the following does not contribute to the formation of the posterior wall of the inguinal canal?
a. Fascia transversalis b. Conjoint tendon c. Lacunar ligament d. Reflected part of inguinal ligament
3. Which is the most important landmark for distinguishing inguinal from femoral hernia?
a. Superficial inguinal ring b. Pubic tubercle c. Midinguinal point d. Inguinal ligament
4. Hernia resulting due to non-return of the umbilical loop of midgut is:
a. Acquired b. Congenital c. Infantile d. None of the above
5. Indirect inguinal hernia coming out at the superficial inguinal ring will have the following coverings:
a. Cremasteric fascia b. Internal spermatic fascia c. External spermatic fascia d. All of the above
6. Which is the covering in all varieties of inguinal hernia?
a. Fascia transversalis b. Internal spermatic fascia c. External spermatic fascia d. All of the above
7. Which type of hernia is commonest in young adults?
a. Lateral direct inguinal b. Medial direct inguinal c. Oblique (indirect) inguinal d. Umbilical
8. The deep inguinal ring lies:
a. ½ inch above mid-inguinal point
b. ½ inch above mid-point of inguinal ligament
c. ½ inch above mid-inguinal point, lateral to inferior epigastric artery
d. Just above pubic tubercle
9. The conjoint tendon is formed by the lower fibres of:
a. External and internal oblique
b. Internal oblique and transversus abdominis
c. Internal oblique and transversus abdominis
d. External and transversus abdominis
10. The cremaster muscle is derived from:
a. External oblique
b. Internal oblique
c. Transversus abdominis
d. Rectus abdominis
11. Which structure lies medial to the deep inguinal ring?
a. Femoral vein
b. Inferior epigastric artery
c. Femoral artery
d. Pectineal ligament
12. The roof of the inguinal canal is formed by:
a. External oblique aponeurosis
b. Fascia transversalis
c. Arched fibres of internal oblique and transversus abdominis
d. Conjoint tendon
13. The superficial inguinal ring transmits all except:
a. Ilioinguinal nerve
b. Spermatic cord
c. Genital branch of genitofemoral nerve
d. Round ligament of uterus (in females)
14. The floor of the inguinal canal is formed by:
a. Fascia transversalis
b. Internal oblique
c. Inguinal ligament and lacunar ligament medially
d. Conjoint tendon
15. In a femoral hernia, the swelling lies:
a. Above and medial to pubic tubercle
b. Below and lateral to pubic tubercle
c. Below and medial to pubic crest
d. Above and lateral to pubic tubercle
16. Which nerve is at risk during herniotomy?
a. Ilioinguinal nerve
b. Pudendal nerve
c. Femoral branch of genitofemoral nerve
d. Iliohypogastric nerve
17. The processus vaginalis is a diverticulum of:
a. Rectus sheath
b. Peritoneum
c. Fascia transversalis
d. Tunica albuginea
18. The main factor preventing inguinal hernia is:
a. Transversalis fascia
b. Obliquity of the canal and shutter mechanism
c. Conjoint tendon
d. External oblique aponeurosis
19. The narrowest part of the inguinal canal is:
a. Deep inguinal ring
b. Superficial inguinal ring
c. Mid-part of canal
d. Neck of hernial sac
20. The cremasteric reflex is mediated by:
a. Iliohypogastric nerve
b. Ilioinguinal nerve (afferent) and genitofemoral nerve (efferent)
c. L1 segment – ilioinguinal and genitofemoral
d. L2–L3 femoral branch
21. The Hesselbach’s triangle is bounded laterally by:
a. Lateral border of rectus abdominis
b. Inferior epigastric artery
c. Inguinal ligament
d. Pubic crest
22. The structure forming the posterior wall of the inguinal canal throughout is:
a. Fascia transversalis
b. Conjoint tendon
c. Transversus abdominis
d. Lacunar ligament
1. What is the length and direction of the inguinal canal?
→ About 4 cm long, directed downwards, forwards, and medially.
2. What are the openings of the inguinal canal?
→ Deep (internal) and superficial (external) inguinal rings.
3. What forms the anterior wall of the inguinal canal?
→ External oblique aponeurosis throughout and internal oblique fibres laterally.
4. What forms the posterior wall of the inguinal canal?
→ Fascia transversalis throughout, reinforced medially by the conjoint tendon.
5. What are the contents of the inguinal canal in males and females?
→ Males: Spermatic cord and ilioinguinal nerve.
→ Females: Round ligament of uterus and ilioinguinal nerve.
6. What are the coverings of the spermatic cord?
→ From inside outward: internal spermatic fascia, cremasteric fascia, external spermatic fascia.
7. What is the conjoint tendon?
→ Fused lower fibres of internal oblique and transversus abdominis, inserted into pubic crest and pectineal line.
8. What is the deep inguinal ring?
→ Opening in fascia transversalis, ½ inch above mid-inguinal point, lateral to inferior epigastric artery.
9. What is the superficial inguinal ring?
→ A triangular gap in external oblique aponeurosis, above and lateral to pubic crest.
10. What is the roof of the inguinal canal?
→ Arched fibres of internal oblique and transversus abdominis.
11. What forms the floor of the inguinal canal?
→ Inguinal ligament throughout, lacunar ligament medially.
12. What is the relation of inferior epigastric artery to deep inguinal ring?
→ Medial to the deep ring — used to distinguish direct and indirect hernias.
13. What are the mechanisms that prevent herniation through the canal?
→ Shutter, ball-valve, slit-valve, and flap-valve mechanisms.
14. What is Hesselbach’s triangle?
→ Area bounded by rectus abdominis (medially), inguinal ligament (inferiorly), and inferior epigastric artery (laterally).
15. What type of hernia passes through Hesselbach’s triangle?
→ Direct inguinal hernia.
16. What is the difference between direct and indirect hernias?
→ Direct: Medial to inferior epigastric artery.
→ Indirect: Lateral to inferior epigastric artery, via deep ring.
17. What is the processus vaginalis?
→ A peritoneal diverticulum that accompanies the testis during descent.
18. What is the cremasteric reflex and its nerve supply?
→ Elevation of testis on stroking the inner thigh — ilioinguinal (afferent) and genitofemoral (efferent).
19. Why is inguinal hernia more common in males?
→ Because of the larger canal and presence of spermatic cord.
20. What is the clinical importance of the ilioinguinal nerve?
→ Supplies upper scrotum or mons pubis and root of penis or labium majus; may cause pain in hernia or after surgery.
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