Sem 2 - D - Pelvic Nerves and Vessels - Sacral plexus, Autonomic nerves, Dermatomes, Branches of Internal Iliac Artery Flashcards

1
Q

What are the roots of the sacral plexus?

A

The sacral plexus is formed by the anterior rami of S1-S4 spinal nerves with contributions from lumbar spinal nerves L4 and L5

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2
Q

What are the nerves of the sacral plexus and the nerve roots?

A
  • Superior gluteal nerve - L4,5, S1
  • Inferior gluteal nerve - L5, S1,2
  • Sciatic nerve - L4,5, S1,2,3
  • Posterior cutaneous nerve of the thigh - S1,2,3
  • Pudendal nerve - S2,3,4
  • Nerve to piriformis - S1,2
  • Nerve to obturator internus - L5, S1
  • Nerve to quaratus femoris - L5, S1
  • Nerve to levator ani - S4
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3
Q

* Superior gluteal nerve - L4,5, S1 * Inferior gluteal nerve - L5, S1,2 * Sciatic nerve - L4,5, S1,2,3 * Posterior cutaneous nerve of the thigh - S1,2,3 * Nerve to obturator internus - L5, S1 * Nerve to quaratus femoris - L5, S1 * Nerve to piriformis - S1,2 * Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

What does the superior gluteal nerves supply? Where does it lie in relation to the piriformis ? How does it leave the pelvis?

A

The superior gluteal nerve (L4,5, S1) leaves the pelvis via the greater sciatic foramen entering the gluteal region superiorly to the piriformis to supply the gluteus medius, gluteus minimus and the tensor fascia lata

It is accompanied by the superior gluteal artery and vein for much of its course.

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4
Q

* Inferior gluteal nerve - L5, S1,2 * Sciatic nerve - L4,5, S1,2,3 * Posterior cutaneous nerve of the thigh - S1,2,3 * Nerve to obturator internus - L5, S1 * Nerve to quaratus femoris - L5, S1 * Nerve to piriformis - S1,2 * Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

What does the inferior gluteal nerves supply? Where does it lie in relation to the piriformis ? How does it leave the pelvis?

A

The inferior gluteal nerve (L5, S1,2) leaves the pelvis via the greater sciatic foramen entering the gluteal region inferiorly to the piriformis to supply the gluteus maximus

It is accompanied by the inferior gluteal artery and vein for much of its course.

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5
Q

* Sciatic nerve - L4,5, S1,2,3 * Posterior cutaneous nerve of the thigh - S1,2,3 * Nerve to obturator internus - L5, S1 * Nerve to quaratus femoris - L5, S1 * Nerve to piriformis - S1,2 * Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

How is the sciatic nerve formed?

A

The sciatic nerve is the largest nerve in the body

It is formed by the lumbosacral trunk (the distal roots of the lumbar plexus which also contribute to the sacral plexus) crossing the pelvic brim to join with S1,2,3 to form the sciatic nerve

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6
Q

* Sciatic nerve - L4,5, S1,2,3 * Posterior cutaneous nerve of the thigh - S1,2,3 * Nerve to obturator internus - L5, S1 * Nerve to quaratus femoris - L5, S1 * Nerve to piriformis - S1,2 * Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

How does the sciatic nerve get from the pelvis to gluteal region? What does the sciatic nerve supply?

A

The sciatic nerve passes through the greater sciatic foramen and arises inferior to the piriformis where it descends down posterior thigh deep to long head of biceps femoris

Motor innervation to the posterior thigh and all muscles leg/foot, sensory to everything below knee except saphenous nerve distribution

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7
Q

* Sciatic nerve - L4,5, S1,2,3 * Posterior cutaneous nerve of the thigh - S1,2,3 * Nerve to obturator internus - L5, S1 * Nerve to quaratus femoris - L5, S1 * Nerve to piriformis - S1,2 * Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

What are the terminal branches of the sciatic nerve and what are there nerve roots?

A

Sciatic nerve two terminal branches - Common fibular nerve, Tibial nerve Common fibular nerve - L4-S2 Tibial nerve - L4-S3

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8
Q

* Posterior cutaneous nerve of the thigh - S1,2,3 * Nerve to obturator internus - L5, S1 * Nerve to quaratus femoris - L5, S1 * Nerve to piriformis - S1,2 * Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

What does the posterior cutaneous nerve of the thigh supply?

A

Posterior cutaneous nerve of the thigh leaves the pelvis via the greater sciatic foramen and enters the gluteal region inferior to the piriformis It has no motor functions and provides sensory innervation to the skin on the posterior surface of the thigh and upper leg

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9
Q

* Nerve to obturator internus - L5, S1 * Nerve to quaratus femoris - L5, S1 * Nerve to piriformis - S1,2 * Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

What are the attachments of the obturator internus muscle?

A

The obturator internus muscles attaches to the pelvic surface of the obturator membrane and the surrounding bones and passes through the lesser sciatic foramen to insert at the medial side of the greater trochanter

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10
Q

* Nerve to obturator internus - L5, S1 * Nerve to quaratus femoris - L5, S1 * Nerve to piriformis - S1,2 * Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

What are the attachments of the gemelli muscles and what do they sandwich?

A

Superior gemelli muscle- arises at ischial spine Inferior gemelii muscles - arises at ischial tuberosity

They sandwich the obturtor internus muscle belly and blend with the tendon of the obturator internus to insert at the medial side of the greater trochanter

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11
Q

* Nerve to obturator internus - L5, S1 * Nerve to quaratus femoris - L5, S1 * Nerve to piriformis - S1,2 * Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

What are the attachments of the quadratus femoris muscle?

A

The quadratus femoris attaches from the ischial tuberosity to the quadrate tubercle on the intertrochanteric crest of the femur

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12
Q

* Nerve to obturator internus - L5, S1 * Nerve to quaratus femoris - L5, S1 * Nerve to piriformis - S1,2 * Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

What does the nerve to obturator internus supply?

What does the nerve to quadratus femoris supply?

A

Nerve to obturator internus supplies the obturator internus and superior gemellus muscle

Nerve to quadratus femoris supplies the quadratus femoris and inferior gemellus muscle

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13
Q

* Nerve to obturator internus - L5, S1 * Nerve to quaratus femoris - L5, S1 * Nerve to piriformis - S1,2 * Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

Describe the course of the nerve to obturator internus?

A

Nerve to obturator internus arises direct from L5 , S1 and leaves the pelvis via the greater sciatic foramen inferior to the piriformis giving branches to the superior gemellus before re-entering the pelvis via the lesser sciatic foramen after crossing over the ischial spine to pierce the pelvic aspect of the obturator internus

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14
Q

* Nerve to obturator internus - L5, S1 * Nerve to quaratus femoris - L5, S1 * Nerve to piriformis - S1,2 * Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

Describe the course of the nerve to quadratus femoris?

A

The nerve to quadratus femoris arises from L5,S1 and leaves the pelvis via the greater sciatic foramen inferior to the pififormis

It runs anterior to the sciatic nerve before giving branches to the quadratus femoris and inferior gemellus muscle

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15
Q

* Nerve to piriformis - S1,2 * Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

What is the course of the nerve to prifiromis?

A

Nerve to pirfiromis arises from sacral nerves S1 and S2 and travels directly backwards to pierce the anterior surface of the piriformis

Couldnt find a pic showing nerve to piriformis

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16
Q

* Pudendal nerve - S2,3,4 * Nerve to levator ani - S4

What is the muscular part of the pelvic floor also known as?

What muscles make it up and what is there nerve supply?

A

Muscular part of the pelvic floor is the pelvic diaphragm

Pelvic diaphragm = levator ani + coccygeus

  • Levator ani nerve supply - pudendal nerve (S2,3,4) + nerve to levator ani (s4)
  • Coccygeus - direct S4,5 spinal nerves
17
Q

Pudendal nerve - S2,3,4 What is the course of the pudendal nerve?

A

The pudendal nerve arises at S2,3,4 spinal level and exits the pelvis via the greater sciatic foramen inferior to the piriformis before curving around the ischial spine to pass through the lesser sicatic foramen back into the pelvis . It passes through the pudendal canal - canal in the fascia of the obturator internus to reach the perineum

18
Q

What nerves arise from the pudendal nerve?

A

The inferior rectal nerve is given off in the pudendal canal which heads towards the levator ani & external anal sphincter

Pudendal nerve gives off superficial and deep perineal branches

  • Deep - dorsal nerve of penis and clitoris
  • Superficial - posterior scrotal or labial nerves
19
Q

What does the pudendal nerve supply via its branches? Split into motor and sensory supply

A

Pudendal nerve motor innervation:

  • * Perineal neve - levator ani, external urethral sphincter, bulbospongiosus and ischiocavernosus, superficial and deep transverse perineal muscles
  • * Inferior rectal nerve - external anal sphincter

Pudendal nerve sensory innervation:

  • * Perineal nerve - skin of perineum , skin of labia majora and minora (posterior labial nerves), posterior scrotum (posterior scotal nerves)
  • * Inferior rectal - perianal skin, lower 1/3rd anal canal * Dorsal nerve of penis/clitoris - skin of penis/clitoris
20
Q

Where are the superior and inferior hypogastric plexuses situated in males and females?

A

The superior hypogastric plexus is located anterior to the bifurcation of the aorta at L4

From the plexus, sympathetic fibres descend as right & left hypogastric trunks which then travels to the inferior hypogastric plexus which is located either side of the rectum in males, and either side of the rectum/vagina in females

21
Q

What sympathetic nerves will contribute towards the superior and inferior hypogastric plexus?

What plexus do the pelvic splanchnic nerves contribute to?

A

Lumbar splanchnic nerves give sympathetics to superior hypogastrc plexus

Pelvic splanchnic nerves (S2-S4) contribute parasympathetics towards the inferior/superior hypogastric plexus and inferior mesenteric plexus

Sacral splanchnic nerves give sympathetics to the inferior hypogastric plexus, as well as right/left hypogastric trunks

22
Q

What function does the sympathetics have on the rectum? What do sympathetic cause to the internal anal/urethral sphincters? Do sympathetics cause ejaculation or erection? What effects do sympathetics have on the bladder, uterus and arteries?

A

Sympathetics are important in fight and flight and therefore decrease non essential bodily functions * Sympathetics decreases rectal movement * They cause contraction of the internal urethral (sphincter vesciae) and anal sphincters * Sympathetics cause ejaculation - contraction of vas deferens and seminal vesicles * Sympathetics relax the bladder and both relax/contract the uterus * Sympathetics cause vasoconstriction of the arteries

23
Q

What function does the parasympathetics have on the rectum? What do parasympathetic cause to the internal sphincters? Do parasympathetics cause ejaculation or erection? What effects do parasympathetics have on the bladder, uterus and arteries?

A

* Parasympathetics in the pelvis are from S2-S4 pelvic splanchnic nerves * They increase motility in the rectum and anal canal * Parasympathetics relax the internal anal sphincter, cause contraction of the detursor whilst inhibiting contraction of the internal urethral sphincter * Parasympathetics have no effect on seminal vesicles, ductus deferens and uterus) * Parasympathetics cause vasodilaton of arteries - erection

24
Q

State the origin of each of the nerves for male innervation of the perineum

A
  • Dorsal nerve of penis origin - deep perineal branch of pudendal nerve
  • Perineal branch supplying the perineal muscles - pudendal nerve
  • Anterior scrotal nerves - ilioinguinal and genitofemoral nerve
  • Posterior scrotal nerves - perineal branch of pudendal nerve
25
Q

What three nerves supply the sensory innervation to anterior pelvic/perineum skin?

A

Ilioiguinal nerve, genitofemoral nerve, pudendal nerve Pudendal nerve sensory innervation to genitalia

26
Q

Dermatomes Supplying root of penis and scrotum? Supplying base of scrotum? Supplying buttocks? Supplying perineum? Supplying perianal skin?

A

Root of penis and scrotum - S3 Base of scrotum - S4 Buttocks - S3 Perineum - S4 Perianal skin - S5

27
Q

At what level does the common iliac artery divide? Which division mainly supplies the pelvis?

A

At L4, the abdominal aorta will divide into a right and left common iliac artery

These will divide into external and internal iliac arteries at L5

The internal iliac artery will be the main arterial supply to the pelvis with the external iliac artery passing beneath the inguinal ligament to become the femoral artery

28
Q

The internal iliac artery divides into an anterior and posterior division Which division is larger and why?

A

The anterior division is larger as it has more branches

29
Q

What are the branches of the anterior division of the iliac artery?

A
  • Umbilical artery - gives rise to superior vesical artery
  • Obturator artery
  • Inferior vesicle artery (in females vaginal artery)
  • Middle rectal artery
  • Inferior gluteal artery
  • Internal pudendal artery

Also have the uterine artery in females

30
Q

What do the umbilical arteries supply in the foetus? What are the derivatives of the adult umbilical artery?

A

The umbilical artery in the foetus carries deoxygenated blood from foetus to the placenta via the umbilical cord

In the adult, the umbilical artery leaves the medial umbilical ligament, and attaches to the pelvic fascia anteriorly

  • The umbilical artey also gives rise to the superior vesical artery
31
Q

What does the obturator artery supply?

A

The obturator artery travels with the obturator vein and nerve to pierce the obturaot membrane within the obturator canal to supply the medial compartment of the thigh

32
Q

What does the inferior vesical artery supply? What helps the inferior vesicle artery supply the prostate gland and seminal vesicle? What is this arteries equivalent in females?

A

The inferior vesical artery supplies the lower aspect of the bladder in males

  • Inferior vesicle + prostatic arteries supply seminal vesicle
  • Inferior vesicle + internal pudendal + middle rectal provide prostatic arteries for prostate gland

In females, the vaginal artery supplies the lower bladder and vagina

33
Q

What is the course of the inferior gluteal artery? Internal pudendal artery follows the same course as the pudendal nerve

A

Inferior gluteal artery passes inferior to pirfiormis throught the greater sciatic notch to enter the gluteal region where it supplies gluteal muscles (travels with the inferior gluteal nerve)

34
Q

What does the uterine artery supply? What does it travel within? WHat will the internal pudendal artery give branches to just before piercing the urogenital diaphragm?

A

Uterine artery travels within the cardinal ligament (transverse cervical ligament) to supply uterine tubes, fundus, ody, cervix and part of vagina Vaginal artery supplies middle part of vagina Internal pudendal artery gives some branches to vagina before piercing the urogenital diaphragm

35
Q

We have discussed the arteries branching from the anterior division of the internal iliac artery

  • * Umbilical artery
  • * Obturator artery
  • * Inferior vesical artery (vaginal artery in females)
  • * Middle rectal artery
  • * Inferior gluteal artery
  • * Internal pudendal artery

What are the branches of the posterior division of the internal iliac artery?

A

* Iliolumbar artery

* Lateral sacral artery

* Superior gluteal artery

36
Q

What odes the iliolumbar artery supply?

A

The iliolumbar artery ascends from the posterior trunk to exit the pelvis giving an iliac and lumbar branch Iliac branch supplies the muscles and bone around the iliac fossa Lumbar branch supplies the psoas pajor, quadratus lumborum and posterior abdominal wall

37
Q

What do the lateral sacral arteries supply? Describe the course of the superior gluteal artery?

A

Lateral sacral arteries travel inferomedially to supply structures in the sacral canal and skin and piriformis Superior gluteal artery exits the pevlis with the vein and superior gluteal nerve via the greater sciatc notch superior to the piriformis

38
Q

What artery does the arty to vas deferens branch from?

A

The artery to vas deferens is a branch of the inferior vesical artery (stated in inguinal canal and scrotum lecture)

39
Q

What level does the internal iliac veins joint to form the inferior vena cava?

A

The internal iliac vein join at L5 to form the IVC

Prostatic venous plexus ad sacral plexus drain into internal iliac veins