Midterm III: Lumbar + Sacral Plexus (Ben) Flashcards Preview

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Flashcards in Midterm III: Lumbar + Sacral Plexus (Ben) Deck (18):

What are the 6 main branches of the lumbar plexus?

  1. Iliohypogastric n. (Th12-L1)
  2. Ilioinguinal n. (Th12-L1)
  3. Genitofemoral n. (L1-L2)
  4. Lateral Femoral Cutaneous n. (L2-L3)
  5. Femoral N. (L2-L4)
  6. Obturator N. (L2-L4)




What does the iliohypogastric nerve innervate?

Motor: Internal Oblique + Transverse Abdominal M.

Sensory: Lateral Gluteal + Lower Abd. Skin



What does the ilioinguinal nerve innervate?

How does it get there?

via the inguinal canal...

male: scrotum skin

female: labia majora


What are the two branches of the genitofemoral nerve?

Their paths?

Their innervations?

Genital Branch

  • inguinal canal
  • motor: cremaster muscle
  • sensory: scrotum + genitals

Femoral Branch

  • lacuna vasorum
  • sensory: femoral triangle skin


Through what does the lateral femoral cutaneous nerve travel to get to its site of innervation?

lacuna musculonervosa


What are the 3 branches of the femoral nerve?

(Two are actually sets of branches.)

  1. Rami Musculares
    • Quadriceps Femoris
    • Sartorius
    • Pectineus (only adductor not via obt. n.)
  2. Saphenous Nerve
  3. Anterior Femoral Cutaneous Branches


What 3 muscles are innervated by the rami musculares of the femoral nerve?

(One is actually a group of muscles)

  • Quadriceps femoris
  • Sartorius
  • Pectineus


What does the saphenous nerve innervate?

Through what does it travel to get there?

via the adductor canal and vastoadductor membrane

it innervates the anterior lower leg


What does the obturator nerve innervate?

Via what space?

adductors (except pectineus!)

via obturator canal


What are the "two parts" of the sacral plexus?

From which spinal segments?

  1. Sciatic Plexus (L4-S3)
  2. Pudendohemorrhoidal Plexus (S3-S4)


What part of the sciatic plexus arises from L4/L5?

lumbosacral trunk

- nervous tissue connecting lumbar and sacral plexuses



What branch of the sacral plexus travels through the suprapiriform hiatus?

To innervate what?

Superior Gluteal Nerve

  • tensor fascia latae
  • gluteus medius
  • gluteus minimus


What 5 muscles do the rami musculares of the sacral plexus innervate?


  1. Obturator Internus
  2. Superior Gemelli
  3. Inferior Gemelli
  4. Quadratus Femoris
  5. Piriformis


What 2 branches of the sciatic plexus pass through the infrapiriform hiatus?

(note this is just the "sciatic" plexus, not the whole sacral plexus)

  1. Sciatic Nerve 
    • ​​(tibial + common peroneal n.)
  2. Inferior Gluteal Nerve 
    • (gluteus maximus)


What cutaneous nerve arises from S1-S3 of the sciatic plexus?

Posterior Femoral Cutaneous N.


What is the "separate" plexus arising from S3-S4?

What is its one nerve?

+ its innervated structures?

Pudendohemorrhoidal Plexus

Pudendal Nerve

  • levator ani
  • pelvic diaphragm
  • pelvic viscera


Describe the path of the pudendal nerve.

Leaves the infrapiriform hiatus...

Re-enters the lesser sciatic foramen...

Enters the ischiorectal fossa and travels in Alcock's canal.