Perineum II Flashcards

1
Q

What are the boundaries of the deep pouch?

A

the two layers of UGD fascia, the superior fascia of the UG diaphragm and the perineal membrane (inferior fascia of the UG diaphragm)

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2
Q

What are the boundaries of the superficial pouch?

A

the perineal membrane superiorly and by Colles’ fascia inferiorly. We saw that the superficial pouch is a more extensive space in the male than in the female.

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3
Q

What are the components of the body of the penis?

A

the corpus spongiosum and the right and left corpora cavernosa.

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4
Q

What is the end of the corpus spongiosum called?

A

the glans of the penis

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5
Q

What are the layers of penile tissue from external to internal?

A
  1. Skin
  2. Superficial penile fascia—remember, this is a continuation of Colles’ fascia in the penis
  3. Deep penile fascia (a.k.a. Buck’s)—this is a layer of deep connective tissue overlying the tunica albuginea
  4. Tunica Albuginea—this is the capsule of the cavernous bodies
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6
Q

What is the blood supply to the right and left corpora cavernosa?

A

the deep arteries of the penis

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7
Q

What artery supplies the corpus spongiosum and distal urethra?

A

The artery to the bulb

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8
Q

Where do the dorsal arteries of the penis lie in the penis?

A

between Buck’s fascia and the tunica albuginea on the dorsal side of the penis

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9
Q

What do the dorsal arteries of the penis do?

A

They supply the skin and subcutaneous tissues of the penis.

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10
Q

What do the Superficial and deep dorsal veins do?

A

drain blood from the penis to the internal pudendal vein

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11
Q

Where are the Superficial and deep dorsal veins located in the penis?

A

on either side of Buck’s fascia in the midline in the dorsum of the penis (so caudal to the corpora cavernosa

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12
Q

What is the the sensory (GSA) innervation to the penis?

A

Dorsal nerve of the penis (3rd branch of the pudendal nerve)

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13
Q

What are the two mechanisms for suspending the penis?

A

First, the body of the penis is supported by two condensations of deep fascia—the fundiform ligament which is derived from the linea albea and the suspensory ligament of the penis which attaches to the symphysis pubis. These ligaments help to suspend the shaft of the penis by forming a sling‐like support mechanism.

A second source of support for the penis is something called the root of the penis.

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14
Q

What are the contents of the scrotum?

A

distal spermatic cord, testis, epididymis

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15
Q

The sides and anterior aspect of the testis are covered by a closed sac of peritoneum called what?

What are its layers?

A

the tunica vaginalis. It consists of parietal and visceral layers with a small volume of serous fluid contained within the intervening space.

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16
Q

The tunica vaginalis is the remnant of what?

A

the processus vaginalis

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17
Q

What is the composition of the testes?

A

Each testis is comprised internally of seminiferous tubules and interstitial tissue surrounded by a thick connective tissue capsule called the tunica albuginea, which lies deep to the viseral layer of tunica vaginalis

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18
Q

What is produced by the seminiferous tubules?

A

Spermatozoa (which ultimately drain into the epididymis)

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19
Q

Where do the epididymus sit on the testes?

A

It occupies the posterolateral aspect of the testis

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20
Q

The tail of the epididymis is continuous with what structure?

A

the vas deferens

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21
Q

What is the blood supply to the scrotum?

A

perineal branch and the external pudendal branches of the femoral artery

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22
Q

What provides sensory innervation of the scrotum?

A

the ilioinguinal nerve, the genital branch of the genitofemoral nerve, the posterior nerve of the scrotum (from the perineal nerve) and posterior cutaneous nerve of the thigh.

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23
Q

What is a varicocele?

A

results when the pampiniform plexus of veins surrounding the spermatic cord becomes varicose (enlarged). Defective valves within the veins of the plexus or compression of the testicular vein in the abdomen can cause dilation of the tributaries to the pampiniform plexus of veins within the scrotal sac.

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24
Q

What is varicocele clinically recognized by?

A

Varicoceles are characterized by an aching pain within the scrotum, accompanied by a visible, palpable mass in the scrotum

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25
Q

What side are varicoceles are more common on?

A

the left side due to the fact that the left testicular vein drains first into the left renal vein. The left renal vein may be compressed during is course between the SMA and the abdominal aorta (nutcracker relationship).

Compression at this site will impede venous drainage of the pampiniform plexus, resulting in a left‐sided varicocele.

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26
Q

The external genitalia are more complex in the female and are collectively referred to as the?

A

vulva

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27
Q

What do the greater vestibular glands (a.k.a. Bartholin’s glands) do?

A

These glands are responsible for the secretion of mucus in response to sexual excitation to provide lubrication for the labia.

28
Q

The body of the clitoris is similar to the body of the penis except for what?

A

it is formed by two (rather than three) cylindrical caverous bodies (the right and left corpura cavernosa)

29
Q

Where is the root of the penis found and what are its contents?

A

It is found deep to the scrotum and it consists of the right and left crura (Latin for “leg”) of the penis which are continuous with the corpora cavernosa and the bulb of the penis which is continuous with the corpus spongiosum.

30
Q

What are the two muscles associated with the root of the penis?

A

Bulbospongiosus muscle and the Ischiocavernosus Muscle

31
Q

Where does the male bulbospongiosus muscle run from?

A

extends from the perineal body and covers the bulb of the penis and the posterior portion of the corpus spongiosum

32
Q

What is the function of the male bulbospongiosus muscle?

A

a) compresses the penile part of the urethra and empties it of residual urine or semen
b) The anterior fibers also compress the deep dorsal vein of the penis, thus impeding venous drainage of the erectile tissue and assisting in maintaining erection.
c) Reflex contraction of these muscles during ejaculation is responsible for pulsatile release of semen

33
Q

Where does the male Ischiocavernosus Muscle run from?

A

arise from the ischiopubic rami and covers the crus of the penis on each side

34
Q

What is the function of the male ischiocavernosus muscle?

A

The action of each muscle is to compress the crus penis and assist in erection by forcing blood into the body of the penis/clitoris.

35
Q

Where does the male Superficial Transverse Perineal Muscle run?

A

Each muscle arises from the ischial tuberosisty and is inserts into the perineal body.

36
Q

What is the function of the male Superficial Transverse Perineal Muscle?

A

The function of these muscles is to fix and stabilize the perineal body in the center of the perineum. This muscle is not associated with the root of the penis

37
Q

The male Superficial Transverse Perineal Muscle, bulbospongiosus, and the ischiocavernosus muscles are innervated by what nerve?

A

the perineal branch of the pudendal nerve

38
Q

In the female, what does the root of the clitoris consist of?

A

the right and left crura of the clitoris which are continuous with the corpura cavernosa and the bulb of the vestibule which is analogous to the bulb of the penis

39
Q

Describe the bulb of the vestibule

A

Due to the position of the vaginal canal, the bulb of the vestibule is divided into two halves which are firmly attached to the UG diaphragm. Note that the bulb of the vestibule gives rise to the glans of the clitoris.

40
Q

Where are Greater Vestibular Glands (Bartholin’s) located and what do they do?

A

located just posterior to the each half of the bulb of the vestibule. These are accessory reproductive glands of the female that secrete mucus to lubricate the vulva during sexual excitation.

41
Q

Where does the female Bulbospongiosus muscle run from and what is its function?

A

extends from the perineal body to surround the orifice of the vagina and cover the vestibular bulbs. Its fibers extend forward to attach to the corpora cavernosa. Its function is to reduce the size of the vaginal orifice and compress the deep dorsal vein of the clitoris assisting in maintaining erection.

42
Q

Where does the female ischiocavernosus muscle run from and what is its function?

A

arises from the ischiopubic ramus and covers the crus of the clitoris on each side. The action of each muscle is to compress the crus clitoris and assist in erection

43
Q

Where does the female Superficial Transverse Perineal Muscle run from and what is its function?

A

Each muscle arises from the ischial ramus and is inserts into the perineal body. The function of these muscles is to fix the perineal body in the center of the perineum. This muscle is not associated with the root of the clitoris.

44
Q

The female superficial transverse perineal muscle, bulbospongiosus, and the ischiocavernosus muscles are innervated by what nerve?

A

perineal nerve (just like in men)

45
Q

T or F. The perineal body is larger than that of the male. Why or why not?

A

It helps to support the posterior wall of the vagina, and the weight of the female pelvic reproductive organs

46
Q

Describe the route of the perineal nerve

A

The perineal nerve is the 2nd branch of the pudendal nerve. It enters the superficial perineal space by passing through the posterior margin of the Colles’ fascia and travels superficial (or inferior) to the UG diaphragm on the surface of the perineal membrane

47
Q

What doe the perineal nerve do?

A

a) motor innervation to the five muscles of the perineum (3 superficial and 2 deep)
b) supplies sensory innervation to the majority of the scrotum/labia, the bulb of the penis/vestibule and the urethra.

48
Q

What does the perineal artery supply?

A

supply the perineal muscles and posterior aspect of the scrotum/labia. Basically all of the superficial pouch

It travels on the superficial surface of the perineal membrane with the perineal nerve.

49
Q

What two muscles make up the UG diaphragm?

A

the external sphincter ureathrae muscle and the deep transverse perineal muscles

50
Q

What is the function of the external sphincter urethrae muscle?

A

This muscle compresses the membranous part of the urethra and relaxes during micturation. It is also the means by which micturation can be voluntarily stopped. It is innervated by branches of the perineal nerve which pierce the perineal membrane.

51
Q

Deep Transverse Perineal Muscles

A

each muscle arises from the ischial ramus and inserts medially at the perineal body. It contributes to the stability of the perineal body and support of pelvic viscera. It is innervated by branches of the perineal nerve which pierce the perineal membrane

52
Q

Where does the Dorsal Nerve of the clitoris/penis come from?

A

the last branch of the pudendal nerve

53
Q

What is the function of the Dorsal Nerve of the clitoris/penis?

A

travels within the deep compartment and provides sensory innervation to the body and glans of the clitoris/penis

54
Q

Does the internal Pudendal Artery travel within the deep perineal pouch?

A

Yes (and many of its distal branches)

55
Q

What are the distal branches of the internal pudendal artery that pass through the

A

1) artery to the urethra
2) Artery to the Bulb of the Penis/Vestibule
3) Deep Artery of the Penis/Clitoris
4) Dorsal Artery of the Clitoris/Penis

56
Q

What does the artery to the urethra do?

A

supplies the urethra

57
Q

What does the Artery to the Bulb of the Penis/Vestibule do?

A

supplies the bulb of the penis/vestibule

58
Q

What does the Deep Artery of the Penis/Clitoris do?

A

responsible for erection

59
Q

What does the Dorsal Artery of the Clitoris/Penis do?

A

supplies the skin, subcutaneous tissues of the clitoris/penis

60
Q

What do Bulbourethral glands (Cowper’s) do?

A

In males, they secrete clear mucus during sexual excitation to lubricate the urethral orifice and the glans penis. The drain into the spongy urethra at the bulb and function to lubricate the urethra. These are the homologues of the female greater vestibular glands.

61
Q

What is erection stimulated by?

A

parasympathetic innervation by pelvic splanchnic nerves (S2-S4) in both men and women. Preganglionic splanchnic nerves enter into the inferior hypogastric plexus where post-ganglionic fibers innervate the erectile tissue of the penis/clitoris via the cavernous nerves from the prostatic/vesicular plexuses

62
Q

What is emission controlled by?

A

sympathetic L1-L2 lumbar splanchnic

63
Q

What is ejaculation controlled by?

A

combination somatic and sympathetic mediated by pudendal nerve and L1-L2 lumbar splanchnic

64
Q

What are Some options for anesthesia during childbirth?

A
  1. General Anesthesia
  2. Regional Anesthesia
    A. Spinal nerve block—anesthesia is introduced via a needle into the subarachnoid space at L3/L4, produces complete anesthesia from about the waist down.
    B. Caudal epidural block—anesthesia is administered into the epidural space via an in‐dwelling catheter in the sacral canal to bath the S2‐S4 spinal roots. This has the advantage that the lower limbs are not usually affected by the anesthesia.
    C. Pudendal nerve block—peripheral nerve block that provides local anesthesia of the S2‐S4 dermatomes.
65
Q

Pudendal nerve block

A

Pudendal nerve block is often performed to relieve the pain of childbirth. The injection of local anesthetic is usually given where the pudendal nerve crosses the lateral aspect of the sacrospinous ligament near the ischial spine.

During childbirth, a finger inserted into the vagina can palpate the ishcial spine. The needle is passed transcutaneously to the medial aspect of the ischial spine and around the sacrospinous ligament.

Does not block pain from the superior birth canal, so the mother is still able to feel uterine contractions.

Additional ilioinguinal nerve block would be necessary to abolish sensation from the anterior part of the perineum.

66
Q

What is an Episiotomy?

A

In some cases, an incision of the perineum and inferoposterior vaginal wall (episiotomy) is performed to enlarge the vaginal opening and prevent tearing.

67
Q

What are some types of episiotomy?

A

Midline episiotomy—through the perineal body

Mediolateral episiotomies—circumvents the perineal body by directing the cut more laterally

Lateral episiotomy—directed even more laterally