femoral canal

-Femoral Canal – Overview

• The femoral canal is the medial compartment of the femoral sheath.

• Unlike the other compartments, it does not transmit major vessels.

• It is filled with loose fibrofatty tissue, lymphatics, and a lymph node (Cloquet’s node).

• Its main function is to allow expansion of the femoral vein when venous return increases.

Femoral Ring.

• The femoral ring is the upper opening (abdominal end) of the femoral canal.

• It is:

  • About ½ inch wide

  • Oval-shaped

• It is normally closed by the femoral septum, which is made of extraperitoneal fat.

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Boundaries of the Femoral Ring

• Anteriorly: Inguinal ligament

• Posteriorly: Pectineal line + pectineus muscle and its fascia

• Laterally: Femoral vein

• Medially: Lacunar ligament (sharp, concave edge

Mnemonic to Remember Femoral Ring Boundaries

Think: “LIP-L” (like lips around the ring)

• L → Lateral → Femoral vein

• I → Inferior (posterior in anatomy position here) → Pectineal line + pectineus

• P → Proximal (anterior) → Inguinal ligament

• L → Medial → Lacunar ligament

👉 Or a simpler phrase:
“V-I-P-L” (Vein, Inguinal, Pectineal, Lacunar)
Move clockwise from lateral:

• Vein → Inguinal → Pectineal → Lacunar’

What are the boundaries of the femoral ring?

:

• Anterior: Inguinal ligament

• Posterior: Pectineal line + pectineus muscle & fascia

• Lateral: Femoral vein.

• Medial: Lacunar ligament

Extra points:

• Femoral ring = upper opening of femoral canal

• Closed by femoral septum

• Site of femoral hernia (high risk of strangulation)

(Anterior)

Inguinal Ligament

───────

Medial Lateral

Lacunar Lig. Femoral Vein

│ │

│ ○ │ ← Femoral ring

│ │

Pectineal Line

+ Pectineus Muscle

(Posterior).

.Clinical Hook (helps memory stick)

• The lacunar ligament (medial) is sharp →
  👉 this is why strangulation of femoral hernia is common

.🧠 Functions of Femoral Canal

👉 Think: “V-L” (VAllows expansion of femoral vein

.Allows expansion of femoral vein

• Acts as a dead space when venous return increases

1. Passage for lymphatics

   • Drains lymph from lower limb → external iliac lymph nodes

Applied Anatomy (Femoral Hernia)’

• The femoral ring is a weak point → site of femoral hernia

• A loop of intestine may protrude into femoral canal

📌Why more common in females?

Think: “Wide + Small + Pressure”

• Wider pelvis → larger femoral canal

• Smaller femoral vessels → more space

• Pregnancy → ↑ intra-abdominal pressure

I🚨 Strangulated Femoral Hernia

‘Treated by cutting the lacunar ligament

• ⚠ Must be careful of:

  • Accessory obturator artery (can be injured → bleeding)

Direction of Femoral Hernia (VERY IMPORTANT)

.👉 Think: “Down → Forward → Up & Lateral”

1. Downward → through femoral canal

2. Forward → through saphenous opening

3. Upward & lateral → along superficial vessels

.Functions of femoral canal + applied anatomy of femoral hernia

Functions:

• Allows expansion of femoral vein (dead space)

• Transmits lymphatics to external iliac nodes

Femoral hernia:

• Occurs through femoral ring (weak point)

• More common in females (wide pelvis, small vessels, pregnancy)

Direction:

• Downward → Forward → Upward & lateral

Clinical:

• Strangulation common

• Lacunar ligament is cut (beware accessory obturator artery)

Q: What is the main function of the femoral canal?.

A: Provides space for expansion of the femoral vein.

Q: What structures pass through the femoral canal?.

‘A: Lymphatics from lower limb to external iliac lymph nodes.

‘Q: Why is the femoral canal called a “dead space”?

A: Because it allows expansion of the femoral vein.

Q: Through which structure does a femoral hernia occur?

A: Femoral ring.

IQ: Why is the femoral ring clinically important?

A: It is a weak point prone to herniation.

Q: Why are femoral hernias more common in females?

A: Wider pelvis, smaller femoral vessels, increased intra-abdominal pressure (pregnancy).

Q: What is the direction of a femoral hernia (step 1)?

A: Downward through femoral canal.

Q: What is the direction of a femoral hernia (step 2)?

A: Forward through saphenous opening.

Q: What is the direction of a femoral hernia (step 3)?

A: Upward and laterally along superficial vessels.

Q: What structure is cut to relieve strangulated femoral hernia?

A: Lacunar ligament.

Q: Which artery is at risk when cutting the lacunar ligament?

A: Accessory obturator artery.

Q: Give a quick summary of femoral canal function and hernia direction.

.
A: Vein expansion + lymphatics; hernia goes Down → Forward → Up & lateral.

Direction of Enlarging Femoral Hernia

1⃣

Think of it as a three-step path:

1. Downward → through the femoral canal

2. Forward → bulges through the saphenous opening

3. Upward & laterally → along the superficial epigastric and superficial circumflex iliac vessels

Mnemonic: “Down → Forward → Up & Lateral” (DFUL)

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2⃣ Coverings of Femoral Hernia (From Inside Out)

1. Peritoneum of hernial sac

2. Femoral septum (extraperitoneal fat)

3. Anterior wall of femoral sheath

4. Cribriform fascia

5. Superficial fascia

Tip: Think “P-F-A-C-S” (Peritoneum → Femoral septum → Anterior wall → Cribriform fascia → Superficial fascia)

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3⃣ Reduction of Femoral Hernia

• Position thigh: slightly flexed & medially rotated → relaxes fascia and ligaments

• Reduce hernia opposite the path of hernial sac (reverse DFUL)

Mnemonic: “Flex, Rotate, Reverse the Flow”

Q: What is the first direction of an enlarging femoral hernia?.

A: Downward through the femoral canal.

Q: What is the second direction of an enlarging femoral hernia?

A: Forward, bulging through the saphenous opening.

Q: What is the third direction of an enlarging femoral hernia?

A: Upward and laterally along superficial epigastric and superficial circumflex iliac vessels.

Q: List the coverings of a femoral hernia from inside outward.

A: Peritoneum → Femoral septum → Anterior wall of femoral sheath → Cribriform fascia → Superficial fascia.

Q: How is a femoral hernia reduced surgically?

A: Thigh slightly flexed & medially rotated, then hernia pushed back opposite to its course.