Somatic innervation to the pelvic organs is –
Correct Answer: Pudendal nerve
Description: Ans. C. Pudendal nervea. Pudendal nerve (in the pelvis)The pudendal nerve arises from the ventral divisions of the second, third and fourth sacral ventral rami and is formed just above the superior border of the sacrotuberous ligament and the upper fibres of ischiococcygeus. It leaves the pelvis via the greater sciatic foramen between piriformis and ischiococcygeus, enters the gluteal region and crosses the sacrospinous ligament close to its attachment to the ischial spine, where it lies medial to the internal pudendal vessels. It accompanies the internal pudendal artery through the lesser sciatic foramen into the pudendal (Alcock's) canal on the lateral wall of the ischio-anal fossa. In the posterior part of the canal it gives rise to the inferior rectal nerve, the perineal nerve and the dorsal nerve of the penis or clitoris.b. Inferior rectal nerveThe inferior rectal nerve runs through the medial wall of the pudendal canal with the inferior rectal vessels. It crosses the ischio-anal fossa to supply the external anal sphincter, the lining of the lower part of the anal canal, and the circumanal skin. It frequently breaks into terminal branches just before reaching the lateral border of the sphincter. Its cutaneous branches distributed around the anus overlap the cutaneous branches of the perineal branch of the posterior femoral cutaneous nerve and of the scrotal or labial nerves. The inferior rectal nerve occasionally arises directly from the sacral plexus and crosses the sacrospinous ligament or reconnects with the pudendal nerve. In females, the inferior rectal nerve may supply sensory branches to the lower part of the vagina.c. Perineal nerveThe perineal nerve is the inferior and larger terminal branch of the pudendal nerve in the pudendal canal. It runs forwards below the internal pudendal artery and accompanies the perineal artery, dividing into posterior scrotal or labial and muscular branches. The posterior scrotal or labial nerves are usually double and have medial and lateral branches which run over the perineal membrane and pass forwards in the lateral part of the urogenital triangle with the scrotal or labial branches of the perineal artery. They supply the skin of the scrotum or labia majora, overlapping the distribution of the perineal branch of the posterior femoral cutaneous and inferior rectal nerves. In females, the posterior labial branches also supply sensory fibres to the skin of the lower vagina.Muscular branches arise directly from the pudendal nerve to supply the superficial transverse perinei, bulbospongiosus, ischiocavernosus, deep transverse perinei, sphincter urethrae and the anterior parts of the external anal sphincter and levator ani. In males, a nerve to the bulb of the urethra leaves the nerve to the bulbospongiosus, pierces this muscle to supply the corpus spongiosum penis and ends in the urethral mucosa.d. Dorsal nerve of the penis or clitorisThe dorsal nerve of the penis or clitoris runs anteriorly above the internal pudendal artery along the ischiopubic ramus deep to the perineal membrane. It supplies the corpus cavernosum and accompanies the dorsal artery of the penis or clitoris between the layers of the suspensory ligament. In males, the dorsal nerve of the penis runs on the dorsum of the penis to end in the glans. In females the dorsal nerve of the clitoris is very small.
Category:
Anatomy
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