femoral nerve

Question 1

What is the origin and root value of the femoral nerve

Answer 1

Origin ⇒ Branch of the Lumbar plexus that is located inside the psoas major muscle in the posterior abdominal wall.

Root value ⇒ Ventral primary rami of L2, L3, L4 (DORSAL divisions of ventral rami)

Question 2

Describe the course, relations and branches of the femoral nerve

Answer 2

1. Femoral N. emerges form the lateral margin of the psoas major muscle and descends to reach the iliac fossa (lying b/w iliacus and psoas major).
   → Suppled branches to ilacus at this level
2. -enters femoral triangle by passing behind inguinal ligament lateral to femoral artery
   -in thigh, lies in groove between iliacus and psoas major outside femoral sheath and
   lateral to femoral artery
3. it terminates into anterior and posterior division about 4cm below the inguinal ligament.

Muscular Branches:
1. From the trunk → Pectineus, iliacus
2. Anterior Division → Sartorius
3. Posterior Division → supplies rectus femoris, 3 vasti and articularis genu

Cutaneous Branches:
1. Anterior Division → intermediate cut nerve of thigh and medial cut nerve of thigh
2. Posterior Division → Saphenous Nerve (longest cutaneous nerve, it passes all the way to the ball of the big toe).

• Articular - hip joint by nerve to rectus femoris knee joint by nerve to 3 vasti
• Vascular – to femoral artery

Question 3

Describe the origin, course, and relations of the saphenous nerve

Answer 3

Origin ⇒ Branch of the posterior division of the femoral nerve and is the longest cutaneous nerve in the body

Course:
1. Leaves the femoral triangle along w/ femoral vessels through the apex to enter the sub sartorial canal.
2. After leaving the sub sartorial canal (adductor canal) (by piercing halfway through the roof of canal). DOES NOT GO THROUGH HIATUS MAGNUS
3. Then it descends vertically along the medial side of knee.
4. Then pierces the deep fascia of the leg b/w tendons of sartorius and gracilis to become superficial
5. In the leg, it descends w/ the great saphenous vein along the medial side
6. Then passes in front of medial malleolus and enters the dorsum of the foot → reaching the base of the big toe

Supply:
⇒ Skin and fascia on the anteromedial aspects of knee, leg, and foot.

Question 4

Describe the Clinical / applied aspects of the femoral nerve

Answer 4

1. Femoral nerve entrapment is very rare
2. Injury to femoral nerve
   → Atrophy of extensor muscles of thigh.
   → Inability to extend the leg at the knee joint.
   → Loss of knee reflex
3. In femoral nerve block, the anesthetic solution is injected at a point one-finger breadth lateral to the point of femoral pulse.