Cutaneous Innervation, Venous Drainage, and Lymphatic Drainage of Lower Limb – Quiz

📝 Practice MCQs

Welcome to your Lower Limb – Chapter 18 – Cutaneous Innervation, Venous Drainage, and Lymphatic Drainage of Lower Limb

The lower vertical group of superficial inguinal lymph nodes drains all of the following except the:

Territory of the short saphenous vein

Superficial fascia of the thigh

Skin of the leg

Skin over the dorsum of the foot

None

A postoperative patient confined to bed develops deep venous thrombosis due to sluggish blood flow in venous sinuses located within which muscle?

Tibialis posterior

Gastrocnemius

Plantaris

Soleus

None

The longest vein in the human body, representing the preaxial vein of the lower limb, is the:

Great (long) saphenous vein

Short saphenous vein

Femoral vein

Popliteal vein

None

A surgeon performs venesection immediately anterior to the medial malleolus. Which structure must be protected during this procedure?

Saphenous nerve

Sural nerve

Common peroneal nerve

Tibial nerve

None

Failure of valves in perforating veins primarily results in:

Reflux of blood from superficial to deep veins

Obstruction of deep venous flow

Reflux of blood from deep veins into superficial veins during muscle contraction

Immediate thrombosis of the femoral vein

None

During embryonic development, medial rotation of the lower limb through 90° causes which structure derived from the preaxial border to assume a medial position in the adult?

Little toe

Great toe

Fibula

Sural nerve

None

An axial line in the lower limb is best defined as a line separating:

Adjacent dermatomes supplied by consecutive spinal segments

Territories of superficial and deep nerves

Ventral and dorsal primary rami

Dermatomes that are not represented by adjacent spinal levels

None

Following injury to the L4 spinal nerve, sensory loss over the lower limb is usually incomplete because:

L4 has no cutaneous distribution

Dorsal root ganglia regenerate rapidly

The skin is supplied only by peripheral nerves

Adjacent dermatomes overlap considerably

None

The skin of the superomedial quadrant of the gluteal region is uniquely supplied by:

Dorsal primary rami of L1–L3 and S1–S3

Ventral primary rami of L1–L5 only

Ventral primary rami of L1–L3

Posterior cutaneous nerve of thigh alone

None

In the leg, the short saphenous vein is characteristically accompanied by the:

Superficial peroneal nerve

Sural nerve

Saphenous nerve

Deep peroneal nerve

None

Time's up

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🎙️ Frequently Asked Viva Questions

Q1. Why is the area of sensory loss after injury to a spinal nerve root smaller than its dermatome?
Answer: Adjacent dermatomes overlap considerably, so neighboring spinal nerves partially compensate for sensory supply.

Q2. Why do the dermatomes of the lower limb follow a spiral pattern?
Answer: The lower limb undergoes 90° medial rotation during embryonic development, carrying its segmental nerves with it.

Q3. Why is the calf muscle called the “peripheral heart”?
Answer: Contraction of the calf muscles compresses deep veins, propelling venous blood upward against gravity.

Q4. Why are valves in perforating veins directed from superficial to deep veins?
Answer: They ensure one-way blood flow into the deep venous system, where the muscle pump efficiently returns blood to the heart.

Q5. Why does prolonged standing predispose to varicose veins?
Answer: Sustained hydrostatic pressure leads to venous valve incompetence, reflux, venous dilation, and tortuosity.

Q6. Why does incompetence of perforating vein valves aggravate varicose veins?
Answer: It allows high-pressure blood from deep veins to reflux into superficial veins during muscle contraction.

Q7. Why is the great saphenous vein commonly used for coronary artery bypass grafting (CABG)?
Answer: It is long, superficial, easily accessible, and can be harvested without significantly impairing venous drainage.

Q8. Why must the saphenous nerve be protected during venesection near the medial malleolus?
Answer: It accompanies the great saphenous vein and may be injured, causing sensory loss over the medial leg and foot.

Q9. Why is deep vein thrombosis common in immobilized postoperative patients?
Answer: Inactivity reduces calf muscle pumping, causing venous stasis in the soleal venous sinuses and promoting thrombosis.

Q10. Why can deep vein thrombosis become life-threatening?
Answer: A thrombus may detach, travel to the lungs, and produce a pulmonary embolism.

Q11. Why is the Trendelenburg test useful in patients with varicose veins?
Answer: It identifies incompetence of the saphenofemoral junction and perforating vein valves by observing abnormal venous filling.

Q12. Why are superficial inguinal lymph nodes enlarged in infections of most of the lower limb?
Answer: They receive lymph from the skin and superficial fascia of most of the lower limb through superficial lymphatics.

Q13. Why do lesions of the sole commonly enlarge the popliteal lymph nodes before the inguinal nodes?
Answer: Lymph from the sole first drains to the popliteal lymph nodes before reaching the deep and superficial inguinal nodes.

Q14. Why does filariasis produce elephantiasis of the lower limb?
Answer: Obstruction of lymphatic vessels by Wuchereria bancrofti causes chronic lymphatic stasis, massive edema, and fibrosis of the limb.