The Perinuem

Question 1

Define the boundaries of the perineal region?

Answer 1

a diamond shaped area bounded by the pubic symphysis, ischial tuberosities and coccyx

Question 2

how is the perineum subdivided?

Answer 2

a line between the ischial tuberosities divide the region into an anterior urogenital triangle and a posterior anal triangle

Question 3

what structure forms the floor of the pelvis (pelvic diaphragm)?

Answer 3

levator ani

Question 4

where are the ischioanal (rectal) fossae located?

Answer 4

on either side of the rectum/anal canal below the levato ani

Question 5

where does the anal canal begin?

Answer 5

on the inferior aspect of the levator ani (floor of the pelvic cavity)

Question 6

what is the dentate/pectinate line?

Answer 6

a line drawn that connects the inferior aspect of the anal valves

Question 7

what is the white/anocutaneous line?

Answer 7

a line inferior to the dentate/pectinate line where the epithelium changes from mucous to stratified squamous

Question 8

what is the anal valve?

Answer 8

a flap of mucosa bridging two anal columns and spanning an anal sinus in the wall of the anal canal

Question 9

what is the anal column?

Answer 9

longitudinal column-like protrusions of epithelium between the anal valves

Question 10

what is the clinical implication of this vavular arrangement?

Answer 10

the small cusp-like flaps of mucosa have anal glands emptying into them. accumulation of fecal material in these cusps can lead to infected glands and abscess situations

Question 11

what are the 2 sphincters of anal canal?

Answer 11

internal and external anal sphincters

Question 12

which of these two sphincters is under voluntary control?

Answer 12

the external is skeletal (voluntary) muscle, the internal smooth (involuntary) muscle

Question 13

what are the 3 components of this latter sphincter?

Answer 13

the subcutatneous, superficial, and deep portions

Question 14

to which two structures is the superficial portion of this sphincter connected?

Answer 14

anteriorly to the perineal body and posteriorly to the coccyx via the anococygeal ligament

Question 15

how does the puborectalis function in assisting the action of the anal sphincter for bowel control

Answer 15

it pulls the lower rectum forward, “kinking” it to add a biochemical sphincter-like feature for continence

Question 16

why is the anocutaneous (white) line important?

Answer 16

it is a major watershed area (shift in supply) for numerous anatomical features/supply

Question 17

list the artererial changes in or around the anocutaneous line

Answer 17

above–superior rectal from inferior mesenteric artery, middle rectal from internal pudendal
below–inferior rectal from internal pudendal

Question 18

List the venous changes in or around the anocutaneous line.

Answer 18

above–to primarily portal system

below–to completely caval system

Question 19

List the lymphatic changes in or around the anocutaneous line.

Answer 19

above–to deep (para-aortic) nodes

below–superficial inguinal nodes

Question 20

List the sensory changes in or around the anocutaneous line.

Answer 20

above--visceral afferents (diffuse pain)
below somatic (sharp, well localized pain) and temperature

Question 21

List the motor changes in or around the anocutaneous line.

Answer 21

above–ANS from pelvic splanchnics to smooth muscle

below–somatomotor from pudendal nerves to skeletal muscle

Question 22

what fills the ischioanal fossa?

Answer 22

fat

Question 23

what forms the roof of the ischioanal fossa?

Answer 23

the underside of the levator ani muscle and deep investing fascia

Question 24

what forms the lateral wall of the ischioanal fossa?

Answer 24

the medial aspect of the obturator internus muscle

Question 25

what forms the medial wall of the ischioanal fossa?

Answer 25

the underside of the levator ani muscle and deep investing fascia

Question 26

what is the relationship of the anterior recess of the ischioanal fossa to the UG diaphragm (deep transverse perineal muscles)?

Answer 26

it is a cavity immediately above the UG diaphragm, continuous with the posteriorly located ischioanal fossa

Question 27

what structures are found within a sheath along the lateral wall of the ischioanal fossa?

Answer 27

the internal pudendal artery and vein and pudendal nerve

Question 28

what is the function of the internal pudendal vessels?

Answer 28

they supply the perineal region and external genitalia

Question 29

what is the pathway of the internal pudendal artery and pudendal nerve prior to its appearance in this fossa?

Answer 29

they left the pelvic cavity via the greater sciatic foramen, passes under the sacrospinous ligament and entered the perineum via the lesser sciatic foramen by passing over the top of the sacrotuberous ligament

Question 30

be able to label a coronal section thru the male and female pelvic/perineal regions

Answer 30

this objective is done in more detail later

Question 31

what is scarpa's fascia?

Answer 31

the deep aspect of the superficial fascia of the lower abdomen and pelvis

Question 32

what does scarpa's fascia form?

Answer 32

the membraneous layer of superficial fascia (scarpa's) can be subdivided into a number of continuous fascial layers in the perineum (buck's, colle's, etc.) that essentially define the outermost extent of the superficial space/pouch

Question 33

what are the contents of the deep perineal space/pouch?

Answer 33

boundaries of the deep perineal space are: the superior fascial layer of the deep transverse perineal muscle, and the inferior fascial layer of the deep transverse perineal muscle--the perineal membrane contents--the deep transverse perineal muscle, the sphincter urethra muscle, the membranous urethra and the bulbourethral glands (in the male). in the female--urethra and vagina

Question 34

what the contents of the superficial perineal space/pouch?

Answer 34

the crura of the penis/clitoris and the ischiocavernosus muscle, the bulb of the penis in the male and the vestibular bulbs in the female, and the overlying bulbospingiosus muscle. in the female the greater vestibular glands are also found in the space.

Question 35

how is the spread of extravasated urine contained?

Answer 35

the membranous layer of the superficial fascia (scarpa's) fuses with the UG diaphragm posteriorly and with the fascia lata of the thigh laterally. it does not therefore spread posteriorly or inferiorly into the thigh.

Question 36

in which space/pouch is this extravasated urine located?

Answer 36

the superficial perineal space/pouch

Question 37

what structures form what used to be called the urogenital (UG) diaphragm?

Answer 37

the deep transverse perineal muscle and the sphincter urethra

Question 38

where is the UG diaphragm located in the male?

Answer 38

at the inferior border of the prostate

Question 39

which of the two structures of the UG diaphragm form is major component?

Answer 39

the deep transverse perineal muscle

Question 40

what structures pierce the UG diaphragm in the male?

Answer 40

the membranous urethra

Question 41

what structures are found along the posterior edge of the deep transverse perineal muscle?

Answer 41

the superficial transverse perineal muscle

Question 42

the penis is composed of how many cylinders of erectile tissue?

Answer 42

3

Question 43

what are the 2 paired dorsal ones called?

Answer 43

corpora cavernosa

Question 44

what is the thick CT capsule of these two cylinders called?

Answer 44

the tunica albuginea

Question 45

what is the single, unpaired ventral cylinder called?

Answer 45

the corpus spongiosum

Question 46

what doesn't the unpaired cylinder have a thick CT capsule?

Answer 46

it does not become as rigid during erection

Question 47

what is the implication of having the urethra traverse this unpaired cylinder?

Answer 47

the urethra must remain patent to allow ejaculation so it does not become as rigid

Question 48

what is the dilated distal end of the corpus spongiosum called?

Answer 48

the glans penis

Question 49

what is the dilated proximal portion of the corpus spongiosum called?

Answer 49

the bulb of the penis

Question 50

what does the shaft of the penis consist of?

Answer 50

3 cylinders of erectile tissue

Question 51

what structures lie under the deep transverse perineal muscle in the male?

Answer 51

the crus and bulb of the penis

Question 52

what muscle layers come the bulb of the penis?

Answer 52

bulbospongiosus

Question 53

what muscle layers cover the crura of the penis?

Answer 53

the ischiocavernosus

Question 54

what fascial layer overlies all of these muscles?

Answer 54

the membranous layer of the superficial (colle's) fascia

Question 55

Be able to label a diagram of the male perineal region in both the lithotomy and coronal views.

Answer 55

The diagrams on the bottom left of page 261 and bottom of page 264 are important and have been used on the exam before

Question 56

what is the outer serous lining on the testis?

Answer 56

the visceral tunica vaginalis

Question 57

where did this serous lining come from?

Answer 57

the peritoneum

Question 58

where is the parietal counterpart to this visceral serous membrane?

Answer 58

on the inside of the scrotal wall

Question 59

what separates one testis from the other?

Answer 59

a fibrous median septum

Question 60

what gives the scrotum its wrinkled appearance? why?

Answer 60

the dartos muscle. the fibers of this muscle insert directly into the skin (no deep fascia covers it)

Question 61

what is the function of the dartos muscle?

Answer 61

it elevates/lowers the testes to keep them at a constant 95 degree temperature. ideal for spermatogensis

Question 62

be aware of the contents of the pudendal cleft in the female, in order from anterior to posterior

Answer 62

clitoris, urethral opening, vaginal opening

Question 63

what is the frenulum and where is it found?

Answer 63

the anterior union of the labia minor, just under the glans clitoris

Question 64

what is the fourchette and where is it found?

Answer 64

the posterior union of the labia minor just posterior to the vagina opening

Question 65

what structures pierce the deep transverse perineal muscle in the female?

Answer 65

the urethra and vagina

Question 66

what structure has separated the bulb of the penis into two smaller bulbs in the female?

Answer 66

the vagina

Question 67

what structures lie under the deep transverse perineal muscle in the female?

Answer 67

the crura of the clitoris and the vestibular bulbs

Question 68

what muscle layers cover the bulbs of the vestibule?

Answer 68

the bulbospongiosus

Question 69

what muscle layer covers the crura of the clitoris?

Answer 69

ischiocavernosus

Question 70

what fascial layers overlies all of the female perineal muscles?

Answer 70

the membranous layer of superficial (colle's) fascia

Question 71

Be able to label a diagram of the female perineal region in both the lithotomy and coronal views as well as a sagittal section through the pelvis that would include the internal reproductive organs.

Answer 71

These diagrams (page 262 and bottom of page 265) have been used on the exam before