Cutaneous Nerves Of Lower Limb

Question 1

Subcostal

Answer 1

T12

Courses along inferior border of 12th rib; lateral cutaneous branch descends over iliac crest

Lateral cutaneous branch supplies skin of hip region inferior to anterior part of iliac crest and anterior to greater trochanter

Question 2

Iliohypogastric

Answer 2

2

L1

Parallels iliac crest; divides into lateral and anterior cutaneous branches

Lateral cutaneous branch supplies supero-lateral quadrant of buttocks

Question 3

Ilioinguinal

Answer 3

3

L1

Passes through inguinal canal; divides into femoral and scrotal or labial branches

Femoral branch supplies skin over medial femoral triangle

Question 4

Genitofemural

Answer 4

4

L1 and L2

Descends anterior surface of psoas major; divides into genital and femoral branches

Femoral branch supplies skin over lateral part of femoral triangle; genital branch supplies anterior scrotum or labia majora

Question 5

Lateral cutaneous nerve of thigh

Answer 5

5

L2 and L3

Passes deep to inguinal ligament, 2–3 cm medial to anterior superior iliac spine

Supplies skin on anterior and lateral aspects of thigh

Question 6

Anterior cutaneous branches

Answer 6

6

L2, 3, 4

Arise in femoral triangle; pierce fascia lata along path of sartorius muscle

Supply skin of anterior and medial aspects of thigh

Question 7

Cutaneous branch of obturator nerve

Answer 7

7

L2, 3, 4

Following its descent between adduc-tors longus and brevis, anterior division of obturator nerve pierces fascia lata to reach skin of thigh

Skin of middle part of medial thigh

Question 8

Posterior cutaneous nerve of thigh

Answer 8

Sacral plexus (S1–S3)

Enters gluteal region via infrapiriform portion of greater sciatic foramen deep to gluteus maximus; then descends deep to fascia lata

Terminal branches pierce fascia lata to supply skin of posterior thigh and popliteal fossa

Question 9

Saphenous nerve

Answer 9

Lumbar plexus via femoral nerve (L3–L4)

Traverses adductor canal but does not pass through adductor hiatus; crossing medial side of knee deep to sartorius tendon

Skin on medial side of leg and foot

Question 10

Superficial fibular nerve

Answer 10

Common bular nerve (L4–S1)

Courses through lateral compartment of leg; after supplying bular muscles, perforates deep fascia of leg

Skin of antero lateral leg and dorsum of foot, excluding web between great and 2nd toes

Question 11

Deep fibular nerve

Answer 11

Common bular nerve (L5)

After supplying muscles on dorsum of foot, pierces deep fascia superior to heads of 1st and 2nd metatarsals

Skin of web between great and 2nd toes

Question 12

Sural nerve

Answer 12

Tibial and common bular nerves (S1–S2)

Medial sural cutaneous branch of tibial nerve and lateral sural cutaneous branch of bular nerve merge at varying levels on posterior leg

Skin of posterolateral leg and lateral margin of foot

Question 13

Median plantar nerve

Answer 13

Tibial nerve (L4–L5)

Passes between rst and second layers of plantar muscles; then between medial and middle muscles of first layer

Skin of medial side of sole, and plantar aspect, sides, and nail beds of medial 3½ toes

Question 14

Lateral plantar nerve

Answer 14

Tibial nerve (S1–S2)

Passes between first and second layers of plantar muscles; then between middle and lateral muscles of first layer

Skin of lateral sole, and plantar aspect, sides, and nail beds of lateral 1½ toes

Question 15

Calcaneal nerves

Answer 15

Tibial and sural nerves (S1–S2)

Lateral and medial branches of tibial and sural nerves, respectively, over calcaneal tuberosity

Skin of heel

Question 16

Superior cluneal nerves

Answer 16

L1–L3 posterior rami

Penetrate thoracodorsal fascia; course laterally and inferiorly in subcutaneous tissue

Skin overlying superior and central parts of buttocks

Question 17

Medial cluneal nerves

Answer 17

S1–S3 posterior rami

Emerge from dorsal sacral foramina; directly enter overlying subcutaneous tissue

Skin of medial buttocks and intergluteal cleft

Question 18

Inferior cluneal nerves

Answer 18

Posterior cutaneous nerve of thigh (S2–S3)

Arise deep to gluteus maximus; emerge from beneath inferior border of muscle

Skin of inferior buttocks (overlying gluteal fold)