Lumbar Plexus

Question 1

what does the lumbar plexus consist of

Answer 1

formed by the anterior rami of the lumbar spinal nerves L1-L4
- also recieves contributions from T12
- the anterior rami of teh L1-L4 spinal roots divide into several cords
- these cords then combine together to form 6 major peripheral nerves of the lumbar plexus
- these nerves then descend down posterior abdominal wall to reach lower limb, where they innervate

lumbar plexus innervates muscles + provides sensation from lower limbs

Question 2

iliohypogastric nerve

Answer 2

roots: L1 + contribtions from T12

motor functions: innervates…
- internal oblique
- transversus abdominis

sensory functions: innervates…
posterolateral gluteal skin in the pubic region

Question 3

ilioinguinal nerve

Answer 3

roots: L1

motor functions: innervates…
- interal oblique
- transversus abdominis

sensory functions: innervates…
- skin on superior antero-medial thigh
- males: skin over root of penis + anterior scrotum
- females: skin over mons pubis + labia majora

Question 4

genitofemoral nerve

Answer 4

roots: L1 + L2

motor functions: genital branch innervates…
cremasteric muscle

sensory functions: innervates…
- genital branch in males: skin of anterior scrotum
- genital branch in females: skin over mons pubis + labia majora
- femoral branch: skin on upper anterior thigh

Question 5

lateral cutaneous nerve of the thigh

Answer 5

roots: L2 + L3

motor functions: none

sensory functions: innervates…
anterior + lateral thigh down to the level of the knee

Question 6

obturator nerve

Answer 6

roots: L2, L3 + L4

motor functions: innervates…
muscles of medial thigh
- obturator externus
- adductor longus
- adductor brevis
- adductor magnus
- gracilis

sensory functions: innervates…
skin over medial thigh

Question 7

femoral nerve

Answer 7

roots: L2, L3 + L4

motor functions: innervates…
muscles of anterior thigh
- iliacus
- pectineus
- sartorius
- quadriceps femoris

sensory functions: innervates…
- skin on anterior thigh
- skin on medial leg

Question 8

what are the nerves of the lumbar plexus

Answer 8

• iliohypogastric (L1 + T12)
• ilioinguinal (L1)
• genitofemoral (L1+L2)
• lateral cutaneous (L2 + L3)
• obturator (L2, L3 + L4)
• femoral (L2, L3 + L4)

i, i get leftovers on fridays