Innervation of the Genitalia and the Pelvic Floor Per Brodal Institutt for medisinske basalfag Universitetet i Oslo 9th Semester 2008

Autonomic Nervous System 2 P. Brodal 2008 Preganglionic neurons Postganglionic neurons

The Autonomic Nervous System 3 P. Brodal 2008 Parasympathetic preganglionic neurons (brain stem) Parasympathetic preganglionic neurons (sacral cord S 2 -S 4 ) Intermediolateral column. Preganglionic sympathetic neurons (T 1 -L 2 ) Pelvic organs

Sympathetic System 4 P. Brodal 2008 Sympathetic trunk Rami communicantes Splanchnic nerve Prevertebral ganglion

The Sympathetic Trunk and Splanchnic Nerves 5 P. Brodal 2008 Sympathetic trunk Communicating rami Spinal nerve Splanchnic nerves

Sacral Parasympathetic Division 6 P. Brodal 2008 Pelvic splanchnic nerves (nervi erigentes) Bladder Rectum Genitals Pelvic plexus and ganglion

Auntonomic Plexuses in the Pelvis 7 P. Brodal 2008 Netter Sympathetic trunk Hypogastric plexus Lumbosacral plexus Pelvic plexus Pudendal nerve

Innervation of the Uterus 8 P. Brodal 2008 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 9 P. Brodal 2008 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 10 P. Brodal 2008 Pontine micturition center – coordination of detrusor and sphincter muscles; mediating voluntary control

The Pudendal Nerve (S 2 -S 4 ) 11 P. Brodal 2008 Thieme Atlas of Anatomy

The Pudendal Nerve and Internal Pudendal Artery Benninghoff/Goertler: Lehrbuc der Anatomie des Menschen, Bd P. Brodal 2008

Motor Innervation of the Pelvic Floor  Levator ani (diaphragma pelvis): innervation by several small branches from the sacral plexus (L 4 -S 5 )  Muscles of the urogenital diaphragm: pudendal nerve (S 2 -S 4 )  Striated sphincter muscles: pudendal nerve  Mid-positioned disc protrusions affect the lower sacral nerves: Danger of permanent incontinence! 13 P. Brodal 2008

Sensory Innervation of the Perineal Region  Color-shaded area shows distribution of cutaneous pudendal branches 14 P. Brodal 2008 Thieme Atlas of Anatomy

Lumbar Plexus Branches to External Genitals 15 P. Brodal 2008 Thieme Atlas of Anatomy 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) 16 P. Brodal 2008

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 17 P. Brodal 2008

Perineal Infiltration in the Second Stage of Labour 18 P. Brodal 2008 Llewellyn-Jones Fanlike injection of local anesthetic Genitofemoral nerve Pudendal nerve

Pudendal Nerve Block 19 P. Brodal 2008

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) 20 P. Brodal 2008