Lumbosacral Plexus Distribution

Question 1

1

Answer 1

subcostal n: lateral cutaneous branch supplies skin inferior to anterior iliac crest

Question 2

2

Answer 2

Iliohypogastric n: lateral cutaneous branch supplies superolateral quadrant of buttock

Question 3

3

Answer 3

Ilio-inguinal n: femoral branch supplies skin over femoral triangle

Question 4

4

Answer 4

Genitofemoral n:

The femoral branch supplies skin over femoral triangle

The genital branch supplies scrotum or labia majora

Question 5

5

Answer 5

lateral femoral cutaneous n: supplies skin on anterior and lateral aspect of thigh

Question 6

6

Answer 6

femoral nerve supplies:

1. sartorius and quadriceps femoris (rectus femoris, vastus lateralis/medialis/intermedius) - the anterior thigh muscles
2. iliacus and pectineus
3. hip and knee joints
4. skin on medial side of thigh

Question 7

7

Answer 7

obturator n:

1. the anterior branch supplies: adductor longus and adductor brevis (L2, L3, L4), gracilis (L2 and L3), and pectineus
2. the posterior branch supplies: adductor magnus (L2, L3, L4) and obturator externus (L3 and L4)

Question 8

8

Answer 8

superior gluteal n supplies:

1. gluteus medius
2. gluteus minimus
3. tensor fasciae latae

Question 9

9

Answer 9

inferior gluteal n supplies:

gluteus maximus

Question 10

10

Answer 10

Nerve to piriformis (from S1 and S2) supplies:

piriformis muscle

Question 11

11

Answer 11

sciatic n supplies:

articular branches to hip and knee joints

(does not supply muscles in the gluteal region)

Question 12

11a

Answer 12

common fibular (peroneal) n (from L4, L5, S1 and S2) supplies:

short head of biceps femoris muscle (via deep peroneal branch)

• • skin on lateral part of posterior aspect of leg via its branch*
• • the lateral sural cutaneous n.*
• • the knee join via its articular branch*

Question 13

11b

Answer 13

Tibial n (from L4, L5, S1-3) supplies:

• The posterior muscles of leg*
  1. long head of biceps femoris
  2. semitendinosus
  3. semimembranosus
• Superficial muscles (from S1 and S2)*
  1. gastrocnemius
  2. soleus
  3. plantaris
• Deep muscles:*
  1. popliteus (from L4, L5, and S1)
  2. flexor hallucis longus (from S2 and S3)
  3. flexor digitorum longus (from S2 and S3)
  4. tibialis posterior (from L4 and L5)

Question 14

12

Answer 14

Nerve to quadratus femoris (and inferior gemellus) supplies the:

quadratus femoris and inferior gemellus

(and the hip joint)

Question 15

13

Answer 15

Nerve to obturator internus (and superior gemellus) supplies the:

obturator internus and superior gemellus

Question 16

14

Answer 16

posterior femoral cutaneous n supplies the:

1. skin of lower buttock (and lateral perineum)
2. uppermost medial and posterior surface of thigh (and posterior aspect of calf and popliteal fossa)

Question 17

15

Answer 17

perforating cutaneous n supplies the:

cutaneous branches to medial part of the buttocks

Question 18

16

Answer 18

pudendal n supplies the:

structures in the perineum (ex: genitalia, external anal sphincter)

also the levator ani muscle (from S4)

Question 19

17

Answer 19

Nerve to levator ani and coccygeus muscles:

levator ani and coccygeus (ischiococcgeus) muscles

Question 20

18

Answer 20

perineal branch of 4th sacral n supplies the:

puborectalis (part of levator ani muscle)

Question 21

19

Answer 21

anococcygeal n supplies the:

Question 22

20

Answer 22

coccygeal n (from S4 and S5) supplies the:

coccygeus muscle

Question 23

11a branches into the deep peroneal nerve, which innervates which muscles?

Answer 23

from L4 and L5: tibialis anterior

from L5 and S1: extensor digitorum longus, extensor hallucis longus, and fibularis (peroneus) tertius.

also the dorsum of foot, skin of first interdigital cleft, and sends articular branches to joins it crosses

Question 24

11a branches into the superficial peroneal nerve, which innervates which muscles?

Answer 24

from L5, S1, and S2: Fibularis longus and Fibularis brevis (also known as Peroneus longus/brevis)