Innervation to pelvis

Question 1

Describe the concept of the ‘pelvic pain line’

Answer 1

• Sensation from pelvic structures touched by peritoneum follow sympathetic innervation.
• Sympathetic innervation comes from the superior hypogastric plexus.
• Sensation from pelvic organs deep to the peritoneum follows parasympathetic (pelvic splanchnic nerves S2-4) supply.

Question 2

What nerve plexus may be injured during a radical hysterectomy during dissection of the parametrial tissues?
What are the short-term complications associated with this nerve plexus injury?

Answer 2

• The inferior hypogastric plexus may be injured.

- Results in voiding dysfunction and urinary retention.

Question 3

What nerve supplies sensory and motor function to the thigh?
What is this nerves’ origin?

What is the name of its branch that may be injured by pressure from a retractor blade during laparotomy and what is the resulting complication?

Answer 3

• Femoral nerve
• Origin: lumbar plexus (L2-4)
• Genitofemoral branch (L1, L2) lies on the surface of the psoas muscle.
• Injury may lead to anaesthesia in the medial thigh and lateral labia.

Question 4

What nerve may be compressed by a retractor placed lateral to the psoas muscle or from hyperflexion of the hip in lithotomy position?

What is the resulting complication?

Answer 4

• Femoral cutaneous nerve (L2, L3)

- Numbness of the anterior thigh

Question 5

What are the six branches of the lumbar plexus

Answer 5

Iliohypogastric (L1)
Ilioinguinal (L1)
Genitofemoral (L1,2)
Lateral cutaneous nerve of the thigh (L2, 3)
Obturator (L2-4)
Femoral (L2-4)

2 from 1, 2 from 2, 2 from 3

L1-4
Psoas major

Question 6

What are the 5 major peripheral nerves of the sacral plexus?

Answer 6

Superior gluteal (L4, L5, S1)
Inferior gluteal (L5, S1, S2)
Sciatic (L4-S3)
Posterior femoral cutaneous nerve (S1-3)
Pudendal nerve (S2-4)

Forms from the anterior rami of S1-4, with contribution from L4 and L5
Located on the surface of the posterior pelvic waLl, anterior to the piriformis