Blocks of Nerves of the Sacral Plexus Supplying the Lower Extremities
Bernard J. Dalens, Jean-Pierre Monnet, Yves Harmand in Pediatric Regional Anesthesia, 2019
The sacral plexus is formed by the union of the ventral rami from L5, S1, S2, S3, and partly from L4 and S4 spinal nerves.11 L4 and L5 ventral rami unite closely at their emergence from intervertebral foramina, thus constituting the lumbosacral trunk which appears at the medial border of the psoas major muscle (Figure 2.28). The lumbosacral trunk runs over the pelvic brim, towards the sacro-iliac joint where it unites with the ventral ramus of the first sacral nerve (Figure 2.1B). The other sacral rami join the plexus just above the greater sciatic notch, thus constituting (1) a lower small band, plexiform in arrangement and prolonged into the pudendal nerve; and (2) an upper large band prolonged by the sciatic nerve, which passes out of the pelvis at this level.
Anatomy
J. Richard Smith, Giuseppe Del Priore, Robert L. Coleman, John M. Monaghan in An Atlas of Gynecologic Oncology, 2018
The sacral plexus (S1−S5) also gives rise to nerves coursing through the pelvis that can be affected by cancers and surgical procedures. The main nerves are the sciatic (L4−S3), pudendal (S3−S4), and the superior (L4−S1) and inferior (L5−S2) gluteal nerves. Lesser nerves are the nerves to quadratus femoris (L4−S1), pirformis (S1−S2) and levator ani and coccygeus (S3−S4); a posterior cutaneous nerve to the buttocks and superior posteromedial thigh (S2−S3), and the nerve to obturator internus (L5−S2). Pelvic splanchnic (S2−S4) nerves supply pelvic viscera via the inferior hypogastric and pelvic plexuses. The sciatic nerve is located laterally to the internal iliac artery where anterior rami converge on the surface of the piriformis. Usually, the sciatic nerve leaves the pelvis along the inferior border of piriformis. However, branches may pass above and/or below (or through) the piriformis, and then merge to form the sciatic nerve. The sciatic nerve can be compromised by inadequate positioning during surgery and by lateral pelvic wall metastases.
Electrophysiological evaluation: Basic principles and clinical applications
Jacques Corcos, David Ginsberg, Gilles Karsenty in Textbook of the Neurogenic Bladder, 2015
Neurological lesions located in the sacral plexus and pudendal nerves are less common than lesions of the cauda equina or conus medullaris. Sacral plexus injuries can be caused by pelvic fractures, hip surgery, complicated deliveries, malignant infiltration, local radiotherapy, and the use of orthopedic traction tables. They are more often unilateral. In principle, unilateral absence of a dorsal penile/clitoral SNAP or absent spontaneous denervation activity in the paravertebral muscles would distinguish a cauda equina/conus medullaris lesion from a sacral plexus or pudendal nerve lesion. However, due to difficulty identifying an unilateral dorsal penile or clitoral nerve for stimulations and absent paravertebral muscles in the lower sacral segments, the above tests would be very difficult. Usually, clinical examination or testing of the first sacral and lower lumbar segments is performed.
Clinical effect of computed guided pudendal nerve block for patients with premature ejaculation: a pilot study
Published in Scandinavian Journal of Urology, 2020
Fouad Aoun, Georges Mjaess, Joseph Assaf, Anthony Kallas Chemaly, Tonine Younan, Simone Albisinni, Fabienne Absil, Thierry Roumeguère, Renaud Bollens
Anatomically, the pudendal nerve is a branch of the sacral plexus [19–21]. It emerges from the S2, S3 and S4 roots, then departs the pelvis from the greater sciatic foramen along with the sciatic roots, between the sacrospinal and the sacrotuberous ligament, and re-enters the pelvis via the lesser sciatic foramen [19–21]. At this level, it releases a superior hemorroidal branch and then cruises through a duplication of the obturator muscle’s fascia called ‘Alcock’s canal’. The pudendal nerve gives rise at the exit of Alcock’s canal to three main branches which are the inferior rectal branch, the perineal branch and the dorsal sensory nerve of the penis or clitoris [19–21]. The pudendal nerve entrapment consists of a compression of this nerve especially between sacrospinous and sacrotuberous ligaments (which constitutes the most common level of entrapment) or in Alcock’s canal [19–21].
Maintaining sexual function after pelvic floor surgery
Published in Climacteric, 2019
S. Jha
Innervation of the vagina arises from hypogastric and sacral plexus. These supply the sympathetic and parasympathetic nerve supply to the pelvic organs whereas the somatic sensory supply is from the pudendal nerve. The clitoris in innervated by the sympathetic (T1–L3) and parasympathetic (S2–S4) fibers with somatic sensory innervation arising from the dorsal nerve of the clitoris. Engorgement of the female genitalia is mediated through the autonomic nerve supply. These structures may be altered during pelvic floor surgery and one hypothesis of genital arousal disorders occurring postoperatively is autonomic denervation of the female erectile tissue.
Does a retrorectal tumour remain a challenge for surgeons?
Published in Acta Chirurgica Belgica, 2019
Eligijus Poškus, Rokas Račkauskas, Donatas Danys, Dileta Valančienė, Tomas Poškus, Kęstutis Strupas
The majority of patients, 19, underwent tumour extirpation through a laparotomy approach, 11 patients were treated with a perineal approach and one patient had to undergo a combined approach. One patient was referred to palliative-only treatment due to tumour invasion into the sacral plexus and major arteries. Three patients had laparoscopic tumour extirpation. Of all the patients who underwent laparotomies, three patients had rectum resection, of which one was with bladder resection; colostomy was performed for two patients. One patient had coccygeal extirpation in conjunction with retrorectal tumour.
Related Knowledge Centers
- Lumbar Vertebrae
- Lumbosacral Plexus
- Lumbosacral Trunk
- Plexopathy
- Spinal Nerve
- Pelvis
- Sacrum
- Body
- Nerve Plexus
- Ventral Ramus of Spinal Nerve