Neuro Flashcards
Anterior scrotal/labial nerves are branches from what nerve?
Ilioinguinal nerve
What do the anterior scrotal/labial nerves innervate?
Anterior scrotum
Anterior labia majora
What innervates the anterior scrotum in males or anterior labia majora in females?
Anterior scrotal/labial nerves
What does the genital branch of the genitofemoral nerve (L1-2) innervate?
Scrotum in males
Labia majora in females
What innervates the scrotum in males and labia majora in females?
Genital branch of genitofemoral n (L1-2)
Describe the obturator nerve (L2-4)
Enters pelvis along lateral pelvic wall
Travels into obturator canal with obturator artery and vein
Branches into anterior and posterior divisions
Innervates medial thigh musculature
What nerve enters the pelvis along lateral pelvic wall, travels into obturator canal with obturator artery and vein, branches into anterior and posterior divisions, and innervates medial thigh musculature?
Obutrator nerve (L2-4)
What does the lumbosacral trunk (L4-5) feed into?
Sacral plexus
What are the pelvic components of the lumbar plexus (L1-L4)?
Ilioinguinal n (L1) Genitofemoral n (L1-2) Lumbosacral trunk (L4-5)
What are the nerves of the sacral plexus (L4-S4)?
Superior gluteal n (L4-S1) Inferior gluteal n (L5-S2) Muscular branches (nerve to quadratus femoris, n to obturator internus, n to piriformis) Posterior femoral cutaneous n (S1-3) Perforating cutaneous branches (S2,3) Pudendal n (S2-4) Sciatic n (L4-S3) Pelvic splanchnic n (S2-4)
What does the superior gluteal nerve (L4-S1) innervate?
Gluteus medius m
Gluteus minimus m
What innervates gluteus medius and gluteus minimus m?
Superior gluteal n (L4-S1)
What does the inferior gluteal nerve (L5-S2) innervate?
Gluteus maximus m
What innervates gluteus maximus m?
Inferior gluteal nerve (L5-S2)
What are the muscular branches of the sacral plexus?
Nerve to quadratus femoris (L4-S1)
Nerve to obturator internus m (L5-S2)
Nerve to piriformis m (S1-2)
What does the posterior femoral cutaneous nerve (S1-3) innervate?
Buttock and uppermost region of posterior thigh
What innervates the buttock and uppermost region of posterior thigh?
Posterior femoral cutaneous nerve (S1-3)
What is the branch off of posterior femoral cutaneous nerve?
Perineal branch to scrotum/labia majora
Where do the perforating cutaneous branches (S2-3) go to?
Medial buttock
What branches from sacral plexus go to medial buttock?
Perforating cutaneous branches
Describe pudendal nerve (S2-4)
To structures of perineum
Produces perineal nerve, inferior rectal nerve, and dorsal nerve of penis/clitoris
What nerve goes to structures of the perineum and produces perineal n, inferior rectal n, and dorsal n of penis/clitoris?
Pudendal nerve (S2-4)
Describe the inferior rectal nerve
Branch of pudendal nerve
Innervates anal canal inferior to pectinate line and external anal sphincter m
What artery from the pudendal nerve innervates anal canal inferior to pectinate line and external anal sphincter m?
Inferior rectal nerve
What does the deep perineal nerve innervate?
Innervates superficial and deep transverse perineal ms, ischiocavernosus m, bulbospongiosus m, vaginal vestibule, and inferiormost part of vagina
What innervates superficial and deep transverse perineal ms, ischiocavernosus m, bulbospongiosus m, vaginal vestibule, and inferiormost part of vagina?
Deep perineal n
What does the superficial perineal nerve produce?
Posterior scrotal n in male
Posterior labial n in female
What is the terminal branch of the perineal nerve in male vs female?
Posterior scrotal nerve
Posterior labial nerve
Where doe the sciatic nerve (L4-S3) travel, and what branches from it?
Through greater sciatic foramen to posterior aspect of thigh
Tibial nerve (L4-S3, lower extremity)
Common fibular nerve (S2-4)
What are part of the coccygeal plexus (S4-5, coccygeal n)?
Anococcygeal nerve Muscular branches (Nerve to levator ani (S4), Nerve to coccygeus (S4-5))
What does the anococcygeal nerve innervate?
Small area of skin in coccygeal region
What innervates a small area of skin in coccygeal region?
Anococcygeal nerve
What are part of the sympathetic division in the pelvis and perineum?
Lumbar sympathetic trunk Lumbar splanchnic nerve Prevertebral ganglia Sacral sympathetic trunk Sacral splanchnic nerve
Describe lumbar splanchnic nerve
Presynaptic sympathetic fibers from lumbar sympathetic trunk L1-L5
Travel primarily to inferior mesenteric ganglion to synapse onto postsynaptic cells, with some postsynaptic fibers feeding into superior hypogastric plexu
What presynaptic sympathetic fibers from L1-5 travel primarily to inferior mesenteric ganglion to synapse on postsynaptic cells?
Lumbar splanchnic nerves
Describe the inferior mesenteric ganlgion
Prevertebral sympathetic ganglion
Lies superior to origin of inferior mesenteric artery
Houses postsynaptic cell bodies corresponding to presynaptic fibers from lumbar splanchnic nerves
With branches from intermesenteric plexus
Describe sacral sympathetic trunk
Paravertebral sympathetic trunk
Continuous superiorly with lumbar sympathetic trunk
4 paired ganglia
Ending inferiorly in midline as ganglion impar
Describe ganglion impar
Coccygeal ganglion
Inferior union of right and left paravertebral trunks
What is the inferior union of the right and left paravertebral trunks?
Ganglion impar
Describe rami communicantes
Postsynaptic sympathetic fibers leaving sacral sympathetic trunk entering ventral rami of sacral and coccygeal spinal nerve to provide sympathetic innervation to lower extremity
What are the postsynaptic sympathetic fibers leaving sacral sympathetic trunk and entering ventral rami of sacral and coccygeal spinal nerve to provide sympathetic innervation to lower extremity?
Rami communicantes
Describe sacral splanchnic nerve?
Postsynaptic sympathetic fibers arising from sacral sympathetic trunk
Feed into inferior hypogastric plexus
What are the postsynaptic sympathetic fibers arising from sacral sympathetic trunk and feeding into inferior hypogastric plexus?
Sacral splanchnic nerve
What are the nerves in the parasympathetic division in the pelvis and perineum?
Pelvic splanchnic nerve
What are the pelvic splanchnic nerves?
Postsynaptic parasympathetic fibers from 2nd through 4th levels of sacral part of spinal cord
Parasympathetic fibers meet with sympathetic fibers of hypogastric nerve to form inferior hypogastric plexus
Visceral sensory fibers accompany parasympathetic fibers of pelvic splanchnic nerves. What do they convey?
Retrograde pain impulses through pelvic splanchnic nerves
into ventral rami of sacral spinal nerves
Onto dorsal root and dorsal root ganglion where cell bodies exist
Finally synapsing in dorsal horn of spinal cord
What is the intermesenteric plexus?
Mixed sympathetic and parasympathetic input from superior mesenteric plexus
Part of aortic plexus
Forms periarterial plexus, which follow gonadal arteries
Feeds into sympathetic into inferior mesenteric plexus and superior hypogastric plexus
What does the ovarian plexus innervate?
Uterine tubes and ovaries
Describe the superior hypogastric plexus
Continuous with intermesenteric plexus and inferior mesenteric plexus
Exclusively sympathetic
Sympathetic input from lumbar splanchnic nerves
Lies anterior to bifurcation of abdominal aorta
Produces ureteric plexus and testicular plexus, which travel along common iliac arteries
Sends paired hypogastric nerve to inferior hypogastric plexus
What does the hypogastric feed into?
Inferior hypogastric plexus
What plexus in the pelvis and perineum is of sympathetic input only?
Superior hypogastric plexus
Describe inferior hypogastric plexus
Mixed sympathetic and parasympathetic
Sympathetic input from hypogastric ns and sacral splanchnic nerves
Parasympathetic input from pelvic splanchnic nerves
In addition to parasympathetically innervating descending and sigmoid colon, it forms multiple subplexuses generically referred to as pelvic plexuses (vesical, uterovaginal, prostatic), and innervates pelvic viscera in males and anal canal above pectinate line in both males and females
Describe the function of the inferior hypogastric plexus to rectum and anal canal
Sympathetic: contraction of internal anal sphincter m
Parasympathetic: inhibits contraction of internal anal sphincter m and stimulates peristalsis
Describe vesical plexus
Mixed sympathetic and parasympathetic
Continuous with inferior hypogastric plexus
Innervates destrusor m and internal urethral sphincter m
What is the function of the vesical plexus to the urinary bladder?
Sympathetic: causes contraction of internal urethral sphincter m
Parasympathetic: causes contraction of detrusor m and relaxation of internal urethral sphincter m
Describe uterovaginal plexus
Mixed sympathetic and parasympathetic
Continuous with inferior hypogastric plexus
Innervates uterus, uterine tubes, vagina, and ovaries
What do cavernosus nerves (female) do?
Parasympathetic innervation to bulbs of vestibule, clitoris, and vestibular glands
Function of cavernosus nerve (Female)?
Produces erection of of clitoris
Engorgement of bulbs of vestibule
Increases vaginal secretion
Visceral sensory fibers from fundus and body of uterus accompany sympathetic fibers of uterovaginal plexus through what?
Autonomic plexus and rami communicantes to spinal
Visceral sensory fibers from cervix of uterus and upper majority of vagina accompany parasympathetic fibers of uterovaginal plexus through what?
Pelvic splanchnic nerves into sacral part of spinal cord
Describe the prostatic plexus
Mixed sympathetic and parasympathetic
Innervates prostate gland and much of male urethra
Describe cavernosus nerves (male)
Convey parasympathetic innervation to helicine arteries that supply erectile tissue
Produce penile erection
Describe nerves of ductus deferens
Mixed sympathetic and parasympathetic
Innervates ductus deferens
Sympathetic: contraction of internal urethral spinchter m, peristalsis-like contraction of ductus deferens
Describe nerves of ejaculatory ducts
Mixed sympathetic and parasympathetic
Innervates ejaculatory ducts
Sympathetic: peristalsis-like contraction of ejaculatory ducts
Describe nerves of seminal vesicles
Mixed sympathetic and parasympathetic
Innervates seminal vesicles
Sympathetic: contraction and secretion of seminal vesciles to add to semen
What are the branches from ilioinguinal nerve (L1)?
Male: anterior scrotal nerve
Female: anterior labial nerve