Abdominal Innervation

Question 1

Parietal/Visceral Innv.

Answer 1

• Parietal: Somatic nerves from SC

- Visceral: Nerves from ANS, Not good @ localizing pain

Question 2

Innervation of Viscera

Answer 2

• Not sensitive to painful stimuli from skin (Burn/crush)

- Stretch/over distention = PAIN

Question 3

Visceral Afferents & Efferents

Answer 3

• Ganglia = number of nerve cell bodies forming a swelling on a nerve fiber
• Plexus = Network of nerves
• Vagus = MAINLY para
• Abdominal Splanchnics= MAINLY sump
• Abdominal Prevert = Pain

Question 4

Vagus

Answer 4

• Craniosacral
• Parasymp. pregang & sensory to viscera of abdomen
• Does NOT supply left 1/2 of TC and DC

Question 5

Abdominal Splanchnics (SNS)

Answer 5

• Thoracolumbar
• Lower thoracic main source of presynaptic symp to abdominal viscera
• Greater: T5-T9/Lesser: T10-T11/Least: T12

Question 6

Abdominal prevert. Ganglia (celiac plexus)

Answer 6

• Largest prevert plexus
• Made of celiac ganglia/fibers
• ant. to crus of diaphragm @ L1
• Ant. to abdominal aorta @ lvl of celiac artery & root of SMA
• post to stomach, omental bursa, pancreas, portal vein & IVC
• INNV: All abdominal contents from foregut to midgut.

Question 7

Abdominal prevert. Ganglia (subsidiary prevert. ganglia)

Answer 7

• celiac ganglia (greater)
• SM ganglia (lesser)
• Aoticorenal ganglia (least)
• IM ganglia (lumbar)

Question 8

Innv. to Foregut/Midgut

Answer 8

• Distal esophagus: greater/lesser splanchnics & vagus
• Stomach: Greater splanchnic
• Dudodenum: Greater/Lesser
• Jejunum & ileum: Splanic & SM plexus

Question 9

Innv. to Hindgut (large intestine)

Answer 9

• Transverse colon: All Splanchnics sympathetic to Superior/inferior mesenteric
• Descending/sigmoid: Superior hypogastric plexus (symp) & pelvic plexus (parasymp)

Question 10

Innv. to Liver

Answer 10

• Hepatic plexus = LARGEST derivative to celiac plexus
• Bilary ducts: Symp from right splanchnic
• VAGUS no pain
• Inflammation causes afferent of parietal causing somatic pain in RUQ

Question 11

Innv. to Pancreas

Answer 11

• Pain splanchnic nerves (greater)

- Vagal NO pain

Question 12

Innv. to Kidney/Ureters

Answer 12

Kidney: Lesser & Least splanchnic (Celiac/Aorticorenal plexus)

• Adrenals: Greater, Lesser, Least (celiac)
• Ureters: Symp. in renal, aortic, Superior/inferior hypogastric plexuses

Question 13

Muscles of posterior wall

Answer 13

• Psoas Major: thigh flexion, trunk flexion, lateral flexion

- Quadratus lumborum: Flex vert. column

Question 14

Nerves of post. abdominal wall

Answer 14

• Obturator: Medial border of psoas (L2-L4)
• Femoral: Lateral border of psoas (L2-L4)
• Lumbrosacral Trunk: L4, L5 & S1-S4
• Ilioinguinal (L1)
• Iliohypogastric (L1)
• Genitofemoral (L1,L2)
• Lateral femoral cutaneous (L2, L3)

Question 15

Pelvic Innervations

Answer 15

• Sup. Hypogastric plexus (presacral): NO parasympathetic
• Sup. Hypogastric: below the bifurcation of abdominal aorta
• Inf. Hypogastric: supplies viscera around rectum & vagina, NO parasympathetic
• Ganglion impar: Sympathetic trunk located front of sacrum (block used to relieve lower back pain)
• Pelvic Splanchnics: NOT sympathetic

Question 16

Bladder Innervation

Answer 16

• Sympathetics: T12, L1, L2
• Parasympathetics: Pelvic Splanchnic -“Nervi erigentes” (arise from S2,S3,S4)
• Somatic afferents: Sacral roots (S2,3,4), NOT sympathetic

Question 17

Innervation of Vagina

Answer 17

• Superior 3/4: Uterovaginal plexus (sacral)
• Lower 1/4: Pudendal nerve (sacral)
• Perineum: Pudendal nerve