Anatomy 2 - nerves of lumbosacral plexus

Question 1

Ilioinguinal nerve

Answer 1

C: L1, lateral border inferior to iliohypogastric, obliquely crosses QL and iliacus, perforates transverse abdominis near anterior iliac crest and communicates with iliohypogastric
M: inferior TA and IO
S: medial femoral triangle

Question 2

Iliohypogastric

Answer 2

C: T12, L1, descends anteriorly to QL, runs past iliac crest posterior to kidnyes. Pierces TA and divides into lateral and anterior cutaneous branches
M: inferior TA and IO
S: supero-lateral quadrant of buttocks

Question 3

Genitofemoral

Answer 3

C: L1, L2, pierces psoas anteriorly before travelling to the inguinal ring and passing through the inguinal canal
M: cremaster in males
S: lateral femoral triangle

Question 4

Lateral femoral cutaneous

Answer 4

C: L2, L3, deep through inguinal ligament and runs towards ASIS
M: nil
S: anterior and lateral thigh

Question 5

Femoral

Answer 5

C: L2, L3, L4 (dorsal), descends from psoas, emerging laterally. Passes under inguinal ligament to enter the femoral triangle
M: iliopsoas, pectineus, sartorius, rectus femoris, vastus lateralis, vastus medalis, vastus intermedius
S: anterior and medial thigh

Question 6

Saphenous

Answer 6

C: L2, L3, L3 (femoral), travels down thigh behind sartorius and enters adductor canal
M: nil
S: medial leg and foot

Question 7

Accessory obturator

Answer 7

C: L3, L4

Question 8

Obturator

Answer 8

C: L2, L3, L4 (ventral), medial to psoas major, passes through obturator foramen to the medial thigh region
M: adductor longus, adductor magnus, adductor brevis, gracilis, obturator externus, pectineus
S: middle 1/3 medial thigh

Question 9

Sciatic

Answer 9

C: L4, L5, S1, S2, S3, enters the thigh via greater sciatic foramen, emerges under piriformis superiorly, lies deep to glute max, descends via greater trochanter and ischial tuberosity, passes over small lateral rotators (SG, OI, IG, QF, OE), crossed by biceps femoris and behind adductor magnus, divides into tibial and common fibular near apex of popliteal fossa
M: branches into tibial and common fibular nerves
S: nil

Question 10

Tibial

Answer 10

C: L4, L5, S1, S2, S3, descends along the posterior thigh and popliteal fossa, passes anteriorly to the arch of soleus with the popliteal artery and descends into the leg before terminating beneath the flexor retinaculum
M: gastroc, soleus, popliteal, TP, FHL, FDL
S: sural, medial calcaneal, lateral plantar, medial plantar

Question 11

Medial calcaneal

Answer 11

Branch of tibial nerve

S: posterior aspect of foot near calcaneus

Question 12

Sural

Answer 12

Branch of tibial nerve

S: anterior and lateral lower leg, dorsum of foot

Question 13

Medial plantar

Answer 13

Branch of tibial nerve
M: AbdH, FDB, FHL (medial head), 1st and 2nd lumbricals
S: medial aspect of plantar surface of foot

Question 14

Lateral plantar

Answer 14

Branch of tibial nerve
M: QP, AddH, AbdHMB, ODM, 3rd and 4th lumbricals, plantar and dorsal interossei
S: lateral aspect of plantar surface of foot

Question 15

Common fibular

Answer 15

C: L4, L5, S1, S2, obliquely descends along lateral popliteal fossa to fibular head, medial to biceps femoris before curbing laterally to the fibular neck deep to fibularlis longus. It then divides into superficial and deep fibular nerves
M: deep and superficial fibular nerves
S: lateral calf

Question 16

Superficial fibular

Answer 16

Branch of common fibular
M: FL, FB
S: cutaneous branch of superficial fibular

Question 17

Deep fibular

Answer 17

Branch of common fibular
M: TA, EHL, EDL, FT
S: cutaneous branch of deep fibular

Question 18

Superior gluteal

Answer 18

C: L5, S1, S2, leaves pelvis through greater sciatic foramen, superior to piriformis
M: gluteus medius, gluteus minimis, TFL
S: nil

Question 19

Inferior gluteal

Answer 19

C: L5, S1, S2, greater sciatic foramen inferior to piriformis and superficial to sciatic nerve
M: gluteus maximus
S: nil

Question 20

Posterior femoral cutaneous

Answer 20

C: S1, S2, S3, passes through greater sciatic foramen deep to gluteus maximus then descends deep to TFL
M: nil
S: posterior thigh and popliteal fossa

Question 21

Pudendal

Answer 21

C: S2, S3, S4
M: pelvic floor muscles
S: genital region