Innervation of the Genitalia and the Innervation of the Genitalia and the Pelvic Floor Pelvic Floor

Per BrodalPer BrodalInstitutt for medisinske basalfagInstitutt for medisinske basalfag

Universitetet i OsloUniversitetet i Oslo

9th Semester 20089th Semester 2008

Autonomic Nervous System

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Preganglionic neurons

Postganglionic neurons

The Autonomic Nervous System

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Parasympathetic preganglionic neurons (brain stem)

Parasympathetic preganglionic neurons (sacral cord S2-S4)

Intermediolateral column. Preganglionic sympathetic neurons (T1-L2)

Pelvic organs

Sympathetic System

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Sympathetic trunk

Rami communicantes

Splanchnic nerve

Prevertebral ganglion

The Sympathetic Trunk and Splanchnic Nerves

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Sympathetic trunk

Communicating rami

Spinal nerve

Splanchnic nerves

Sacral Parasympathetic Division

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Pelvic splanchnic nerves (nervi erigentes)

BladderRectumGenitals

Pelvic plexus and ganglion

Auntonomic Plexuses in the Pelvis

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Sympathetic trunk

Hypogastric plexus

Lumbosacral plexus

Pelvic plexus

Pudendal nerve

Innervation of the Uterus

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All nerves to the uterus pass through the part of the pelvic plexus lying lateral to the cervix (juxtacervical plexus)

Juxtacervical plexus

Innervation of the Bladder

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Striated external sphincter – pudendal nerve S2-S4

MOTOR SENSORY

From the bladder neck: traveling with parasympathetic nerves

From main part of the bladder: with sympathetic nerves

S2-S4

L1

L4

To detrusor: preganglionic parasympathetic fibers from S2-S4

Central Control of Micturition

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Pontine micturition center – coordination of detrusor and sphincter muscles; mediating voluntary control

The Pudendal Nerve (S2-S4)

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The Pudendal Nerve and Internal Pudendal Artery

Benninghoff/Goertler: Lehrbuc der Anatomie des Menschen, Bd. 2

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Motor Innervation of the Pelvic Floor

Levator ani (diaphragma pelvis): innervation by several small branches from the sacral plexus (L4-S5)

Muscles of the urogenital diaphragm: pudendal nerve (S2-S4)

Striated sphincter muscles: pudendal nerve Mid-positioned disc protrusions affect the

lower sacral nerves: Danger of permanent incontinence!

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Sensory Innervation of the Perineal Region

Color-shaded area shows distribution of cutaneous pudendal branches

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Lumbar Plexus Branches to External Genitals

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Iliohypogastric nerve

Ilioingual nerve

Genitofemoral nerve

Iliohypogastric nerve

Genitofemoral nerve (genital branch)

Ilioingual nerve

Sensory Innervation of the External Genitals

Vulva: anterior-posterior division between lumbar plexus and pudendal nerve – but mainly pdendal

Penis: mainly branches from the pudendal nerve

Scrotum: Aanteriorly branches from the lumbar plexus (L1), dorsally branches from the pudendal nerve (S2)

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Pain Conduction in Labour

1. stage• Corpus and upper cervix via ”sympathetic pain fibers”

and dorsal roots T10-L2 2. stage• Subperitoneal structures above the pelvic floor,

including upper vagina, via ”parasympathetic pain fibers” and dorsal roots S2-S4

• Pelvic floor and perineum via ”somatic pain fibers” in n. pudendus and dorsal roots S2-S4

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Perineal Infiltration in the Second Stage of Labour

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Fanlike injection of local anesthetic

Genitofemoral nerve

Pudendal nerve

Pudendal Nerve Block

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Anaesthesia during labour

Infiltration of perineum (skin) Pudendal block (+ block ilioinguinal and posterior

cutaneous of thigh) Paracervical block Sacral (low) epidural anaesthesia (needle in hiatus

sacralis) Lumbar epidural anaesthesia Lumbar subarachnoidal (spinal) block (for sectio)

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