Nerves of the Lumbar Sacral Plexus

Question 1

Subcostal Nerve Root and Path/supply

Answer 1

Roots= T12
Path/supply= Under 12th rib
- supplies external oblique and skin anterior lateral abdominal wall

Question 2

Iliohypogastric & Ilioinguinal nerve root and path/supply

Answer 2

Root= L1
Path/supply= Runs anterior to Quadrate lumborum and superior and parallel to the iliac crest–> then pierces transverse abdominus near ASIS and Run through internal and external obliques to supply abdominal walls

Question 3

Genito femoral Nerve
What 2 nerves
Roots and path/supply

Answer 3

Genital= L1
Femoral = L2
Path/supply= Nerve pierces Psoas major and runs inferiorly on anterior surface
It breaks off into 2 branches lateral to common and external iliac arteries, Genital branch which goes to the genitalia
Femoral branch which goes to supply sensation to the upper anterior thigh/groin region

Question 4

Lateral Femoral Cutaneous Nerve Root and path/supply
What clinical correlation do we see with this nerve?

Answer 4

Root=L2-L3
Meralgia paresthetica from impingement at inguinal ligament
Sight of entrapment of the nerve, it causes paresthesia over lateral groin/thigh region

Question 5

Femoral Nerve Root and path/supply

Answer 5

Root= L2-L4
Motor to quads in anterior thigh
Vulnerable to injury in femoral triangle at inguinal ligament

Question 6

Obturator Nerve Root and path/supply

Answer 6

Root= L2-L4
-To hip adductor muscles
- Emerges from Psoas major and passes to lesser pelvis
-Runs inferior to pubic ramus through obturator foramen to medial thigh to supply hip adductor muscles

Question 7

Sciatic Nerve Root and path/supply

Answer 7

Root= L4-S3
- tibial nerve
common fibular nerve
articular branches to hip joint and muscular branches to flexor of the knee in the thigh and all muscles in the leg/foot

Question 8

Superior Gluteal Root and path/supply

Answer 8

Root=L4-S1
-Distribution to gluteus Medius, gluteus minimis and tensor fasciae latae muscle

Question 9

Inferior Gluteal Root and path/supply

Answer 9

Root=L5-S2
-Distribution to Gluteus Maximus

Question 10

Nerve to Piriformis Root and path/supply

Answer 10

Root= S1-S2
Distribution to piriformis muscle

Question 11

Nerve to Obturator Internus

Answer 11

Root=L5-S2
Distribution to obturator internus and superior gemellus muscle

Question 12

Nerve to quadratus femoris

Answer 12

Root=L4-S1
Distribution to Quadratus femoris ad inferior gemellus muscles

Question 13

Nerve to Levator Ani and Coccygeus muscles

Answer 13

Root=S3-S4
Distribution to Levator Ani and Coccygeus muscles

Question 14

Posterior Femoral Cutaneous

Answer 14

Root=S2-S3
- Cutaneous branches to Buttocks and uppermost medial/posterior surfaces of the thigh
- It runs through the grater sciatic foramen, under piriformis

Question 15

Pudendal Nerve

Answer 15

Root=S2-S4
-Structures in perineum: sensory branches to external genitalia
- muscular branches to perineal muscles, external urethral sphincter and external anal sphincter