Nerves of the Abdomen and Pelvic Regions
Nerve: Cavernous nerve
Origin: Parasympathetic fibers of prostatic nerve plexus
Course: Perforates perineal membrane to reach erectile bodies of penis
Innervation: Helicine arteries of cavernous bodies; stimulation produces engorgement at arterial pressure
Nerve: Clunial
Origin: Posterior rami of L1, L2, and L3; posterior rami of S1, S2, and S3; posterior cutaneous nerve of thigh
Course: Superior nerves cross iliac crest; middle nerve exit through posterior sacral foramina, entering gluteal region; inferior nerves curve around inferior border of gluteus maximus
Innervation: Skin of buttock or gluteal region as far as greater trochanter
Nerve: Coccygeal
Origin: Conus medullaris of spinal cord
Course: Anterior and posterior rami join adjacent rami of S4 and S5; anterior rami form coccygeal plexus, gives rise to anococcygeal nerve
Innervation: Skin over coccyx
Nerve: Genitofemoral
Origin: Lumbar plexus
Course: Descends on anterior surface of psoas major, divides into genital and femoral branches
Innervation: Femoral branch supplies skin over femoral triangle; genital branch supplies scrotum or labia majora; genital branch to cremaster muscle
Nerve: Hypogastric
Origin: Superior hypogastric plexus into pelvis
Course: Sacrum within hypogastric sheath, merges with pelvic splanchnic nerve in inferior hypogastric plexus
Innervation: Pelvic viscera; intraperitoneal pelvic viscera
Nerve: Iliohypogastric
Origin: Lumbar plexus
Course: Traverses abdominal muscle; external oblique aponeurosis to reach inguinal and pubic regions
Innervation: Internal oblique and transverse adbominal muscles; superolateral quadrant of buttock; skin over iliac crest and hypogastric region
Nerve: Ilioinguinal
Origin: Lumbar plexus
Course: Passes between 2nd and 3rd layers of abdominal muscles; inguinal canal, divides into femoral and scrotal or labial branches
Innervation: Lower part of internal oblique, transverse abdominal muscles; skin over femoral triangle; mons pubis, adjacent skin of labia majora or scrotum
Nerve: Inferior anal
Origin: Pudendal nerve
Course: Pudendal canal, medially through ischioanal fat pad to anal canal
Innervation: External anal sphincter; perianal skin
Nerve: Inferior gluteal
Origin: Sacral plexus
Course: Pelvis through greater sciatic foramen inferior to piriformis, divides into several branches
Innervation: Gluteus maximus
Nerve: Lateral cutaneous nerve of thigh
Origin: Lumbar plexus
Course: Deep to inguinal ligament, medial to anterior superior iliac spine
Innervation: Skin on anterior and lateral aspects of thigh
Nerve: Nerve to obturator internus
Origin: Sacral plexus
Course: Gluteal region, greater sciatic foramen, inferior to piriformis; descends posterior to ischial spine; lesser sciatic foramen, to obturator internus
Innervation: Superior gemellus and obturator internus
Nerve: Quadratus femoris
Origin: Sacral plexus
Course: Leaves pelvis through greater sciatic foramen deep to sciatic nerve
Innervation: Inferior gemellus and quadratus femoris; hip joint
Nerve: Obturator
Origin: Lumbar plexus
Course: Enters thigh through obturator foramen, divides into anterior and posterior branches
Innervation: Adductor longus, adductor brevis, gracilis, and pectineus; obturator externus, adductor magnus; skin of medial thigh above knee
Nerve: Pelvic splanchnic
Origin: Sacral plexus
Course: Runs anteriorly and inferiorly to merge with inferior hypogastric plexus
Innervation: Parasympathetic fibers for pelvic viscera, descending and sigmoid colon; subperitoneal pelvic viscera
Nerve: Perineal
Origin: Terminal branch of pudendal nerve
Course: Pudendal nerve from pudenal canal to superficial perineum dividing into superficial cutaneous and deep motor branch
Innervation: Urogenital triangle; skin of posterior urogenital triangle
Nerve: Posterior cutaneous nerve of thigh
Origin: Sacral plexus
Course: Leaves pelvis through greater sciatic foramen inferior to piriformis, deep to gluteus maximus
Innervation: Skin of buttock; skin over posterior aspect of thigh and calf; lateral perineum, upper medial thigh
Nerve: Posterior labial
Origin: Perineal nerve
Course: Pudendal canal and ramifies in subcutaneous tissue
Innervation: Skin of posterior portion of labium majus
Nerve: Pudendal
Origin: Sacral plexus
Course: Enters gluteal region through greater sciatic foramen inferior to piriformis; descends to sacrospinous ligament; perineum through lesser sciatic
Innervation: Most motor and sensory innervation to perineum
Nerve: Sciatic
Origin: Sacral plexus
Course: Enters gluteal region through greater sciatic foramen interior to piriformis; descends along posterior aspect of thigh, divides proximal to knee into tibial and common fibular peroneal nerves
Innervation: Hamstrings; provides articular branches to hip and knee joints
Nerve: Superior gluteal
Origin: Sacral plexus
Course: Leaves pelvis through greater sciatic foramen, superior to piriformis, runs between gluteus medius and minimus
Innervation: Gluteus medius, gluteus minimus, tensor fasciae latae
Origin: Parasympathetic fibers of prostatic nerve plexus
Course: Perforates perineal membrane to reach erectile bodies of penis
Innervation: Helicine arteries of cavernous bodies; stimulation produces engorgement at arterial pressure
Nerve: Clunial
Origin: Posterior rami of L1, L2, and L3; posterior rami of S1, S2, and S3; posterior cutaneous nerve of thigh
Course: Superior nerves cross iliac crest; middle nerve exit through posterior sacral foramina, entering gluteal region; inferior nerves curve around inferior border of gluteus maximus
Innervation: Skin of buttock or gluteal region as far as greater trochanter
Nerve: Coccygeal
Origin: Conus medullaris of spinal cord
Course: Anterior and posterior rami join adjacent rami of S4 and S5; anterior rami form coccygeal plexus, gives rise to anococcygeal nerve
Innervation: Skin over coccyx
Nerve: Genitofemoral
Origin: Lumbar plexus
Course: Descends on anterior surface of psoas major, divides into genital and femoral branches
Innervation: Femoral branch supplies skin over femoral triangle; genital branch supplies scrotum or labia majora; genital branch to cremaster muscle
Nerve: Hypogastric
Origin: Superior hypogastric plexus into pelvis
Course: Sacrum within hypogastric sheath, merges with pelvic splanchnic nerve in inferior hypogastric plexus
Innervation: Pelvic viscera; intraperitoneal pelvic viscera
Nerve: Iliohypogastric
Origin: Lumbar plexus
Course: Traverses abdominal muscle; external oblique aponeurosis to reach inguinal and pubic regions
Innervation: Internal oblique and transverse adbominal muscles; superolateral quadrant of buttock; skin over iliac crest and hypogastric region
Nerve: Ilioinguinal
Origin: Lumbar plexus
Course: Passes between 2nd and 3rd layers of abdominal muscles; inguinal canal, divides into femoral and scrotal or labial branches
Innervation: Lower part of internal oblique, transverse abdominal muscles; skin over femoral triangle; mons pubis, adjacent skin of labia majora or scrotum
Nerve: Inferior anal
Origin: Pudendal nerve
Course: Pudendal canal, medially through ischioanal fat pad to anal canal
Innervation: External anal sphincter; perianal skin
Nerve: Inferior gluteal
Origin: Sacral plexus
Course: Pelvis through greater sciatic foramen inferior to piriformis, divides into several branches
Innervation: Gluteus maximus
Nerve: Lateral cutaneous nerve of thigh
Origin: Lumbar plexus
Course: Deep to inguinal ligament, medial to anterior superior iliac spine
Innervation: Skin on anterior and lateral aspects of thigh
Nerve: Nerve to obturator internus
Origin: Sacral plexus
Course: Gluteal region, greater sciatic foramen, inferior to piriformis; descends posterior to ischial spine; lesser sciatic foramen, to obturator internus
Innervation: Superior gemellus and obturator internus
Nerve: Quadratus femoris
Origin: Sacral plexus
Course: Leaves pelvis through greater sciatic foramen deep to sciatic nerve
Innervation: Inferior gemellus and quadratus femoris; hip joint
Nerve: Obturator
Origin: Lumbar plexus
Course: Enters thigh through obturator foramen, divides into anterior and posterior branches
Innervation: Adductor longus, adductor brevis, gracilis, and pectineus; obturator externus, adductor magnus; skin of medial thigh above knee
Nerve: Pelvic splanchnic
Origin: Sacral plexus
Course: Runs anteriorly and inferiorly to merge with inferior hypogastric plexus
Innervation: Parasympathetic fibers for pelvic viscera, descending and sigmoid colon; subperitoneal pelvic viscera
Nerve: Perineal
Origin: Terminal branch of pudendal nerve
Course: Pudendal nerve from pudenal canal to superficial perineum dividing into superficial cutaneous and deep motor branch
Innervation: Urogenital triangle; skin of posterior urogenital triangle
Nerve: Posterior cutaneous nerve of thigh
Origin: Sacral plexus
Course: Leaves pelvis through greater sciatic foramen inferior to piriformis, deep to gluteus maximus
Innervation: Skin of buttock; skin over posterior aspect of thigh and calf; lateral perineum, upper medial thigh
Nerve: Posterior labial
Origin: Perineal nerve
Course: Pudendal canal and ramifies in subcutaneous tissue
Innervation: Skin of posterior portion of labium majus
Nerve: Pudendal
Origin: Sacral plexus
Course: Enters gluteal region through greater sciatic foramen inferior to piriformis; descends to sacrospinous ligament; perineum through lesser sciatic
Innervation: Most motor and sensory innervation to perineum
Nerve: Sciatic
Origin: Sacral plexus
Course: Enters gluteal region through greater sciatic foramen interior to piriformis; descends along posterior aspect of thigh, divides proximal to knee into tibial and common fibular peroneal nerves
Innervation: Hamstrings; provides articular branches to hip and knee joints
Nerve: Superior gluteal
Origin: Sacral plexus
Course: Leaves pelvis through greater sciatic foramen, superior to piriformis, runs between gluteus medius and minimus
Innervation: Gluteus medius, gluteus minimus, tensor fasciae latae