Pudendal nerve
The pudendal nerve ("pubic nerve") is a nerve of the lumbosacralis plexus and arises from the spinal cord segments S1-S4 (1st – 4th cross segment), depending on the species in mammals . That subsection of the lumbar and cross plexus is also known as the pudendal plexus . The nerve runs in the pelvic cavity caudoventrally in the direction of the pelvic floor (referred to as the pelvic outlet in animals), together with the internal pudendal artery and vein via the infrapiriforme foramen in the pudendal canal (Alcock's canal). The pudendal nerve has several branches:
- Nervi rectales inferiores ( caudales )
- Nervi perineales
- Nervus dorsalis penis or dorsalis clitoridis
The pudendal nerve carries both general somatosensitive and somatomotor nerve fibers.
Inferior rectal nerve
The nervi rectales inferiores ("lower rectal nerves") are referred to in animals as the nervi rectales caudales (posterior rectal nerves) in accordance with the horizontal alignment of the body . They innervate the area around the anus and its sphincter ani externus muscle (external anal sphincter).
Injury to the nerve can lead to incontinentia alvi .
In some mammals, the caudal rectal nerve also innervates the retractor penis (or clitoridis ) muscle and the bulbospongiosus muscle .
Nervi perineales
The nervi perineales ("dam nerves") sensitively innervate the perineum and the muscles of the penis root ( musculus ischiourethralis , musculus ischiocavernosus , musculus bulbospongiosus ). They also supply the striated muscle around the urethra ( urethralis muscle ). These parts of the nerve are referred to in veterinary anatomy as the deep perineal nerve .
The nervi perineales also supply the scrotum and the labia via the nervi scrotales and labiales , and in ungulates also the rear part of the udder . In animals, these branches are also known as the superficial perineal nerve .
Damage to the perineal nerves lead u. a., due to paralysis of the urethralis muscle, to urinary incontinence .
Nervus dorsalis penis / Nervus dorsalis clitoridis
The nervus dorsalis penis (back of the penis nerve) is referred to in female individuals as the nervus dorsalis clitoridis (clitoris nerve). It is the direct terminal branch of the pudendal nerve and the most important sensitive nerve of the glans penis or the clitoris . Since it is responsible for conveying sexual sensations, it is also referred to as the "lust nerve".
Pudendus block
To relieve the pain in childbirth, the pudendal nerve can be numbed with a pudendal block during childbirth . To do this, a long needle is used to inject an anesthetic through the vaginal wall at several points, which numbs the pudendal nerve for about an hour. This primarily relieves the pain in the vagina area ; the urge to press does not subside .
Since there is a fundamental risk of hitting the head of the unborn child with the cannula, the pudendus block is primarily used for suction cup or forceps delivery.
literature
- Franz-Viktor Salomon: nervous system, systema nervosum. In: Franz-Viktor Salomon, Hans Geyer, Uwe Gille (Ed.): Anatomy for veterinary medicine. Enke, Stuttgart 2004, ISBN 3-8304-1007-7 , pp. 464-577.