Perineum and External Genitalia - Anatomy

Question 1

What divides the perineum into the urogenital and anal triangle?

Answer 1

Imaginary line between ischial tuberosities

Question 2

What does the anal triangle contain?

Answer 2

• Anal opening
• Anal aperture
• Ischioanal fossa x2

Question 3

What is ischioanal fossa?

Answer 3

Fat filled space between ischium and anus

Question 4

What does ischioanal fossa allow for?

Answer 4

Expansion during defecation

Question 5

What forms the lateral boundary of the ischioanal fossa?

Answer 5

Obturator internus

Question 6

What forms the medial boundary of the ischioanal fossa?

Answer 6

Levator ani

Question 7

What forms the inferior boundary of the ischioanal fossa?

Answer 7

Subcutaneous fat and tissue

Question 8

Describe the course of the internal pudendal artery / nerve / vein

Answer 8

Leaves pelvis via greater sciatic foramen, loops around sacrospinous ligament and enters into perineum via lesser sciatic foramen

Question 9

What branches does the internal pudendal artery give off?

Answer 9

Branches to levator ani, inferior rectal branches

Question 10

Where does the pudendal neurovascular bundle course?

Answer 10

In ischioanal fossa

Question 11

Describe the course of the piriformis muscle

Answer 11

Leaves pelvis via greater sciatic foramen to attach to the femur

Question 12

What can the urogenital triangle be divided into?

Answer 12

Superficial and deep perineal pouches

Question 13

What separates the superficial and deep perineal pouches?

Answer 13

Perineal membrane

Question 14

Where does the perineal membrane project from/to?

Answer 14

Membrane projects from ischiopubic ramus to ischial tuberosities

Question 15

What are the only openings that the perineal membrane contains?

Answer 15

Opening for urethra and vagina in female

Question 16

What does the perineal membrane act as?

Answer 16

Perineal membrane acts as an attachment point for the external genitalia, so external genitalia hang and are located in the superficial perineal pouch

Question 17

What is found deep to the perineal membrane?

Answer 17

The external urethral sphincter and deep transverse perineal muscles

Question 18

What is found superficial to the perineal membrane?

Answer 18

Erectile tissues and associated muscles

Question 19

Where does the bulb of the penis hang from?

Answer 19

Perineal membrane in the midline

Question 20

What muscle surrounds the bulb of the penis?

Answer 20

Bulbospongiosus

Question 21

What does the bulb of the penis project forward as?

Answer 21

The corpus spongiosum

Question 22

What is the corpus spongiosum?

Answer 22

An erectile chamber that attaches to perineal membrane at the bulb of the penis where it is covered by bulbospongiosus muscle

Question 23

What does the corpus spongiosum contain?

Answer 23

Penile urethra

Question 24

What surface does the corpus spongiosum form?

Answer 24

Ventral surface

Question 25

How does the corpus spongiosum terminate?

Answer 25

Dilates to form glans penis

Question 26

What is found laterally to bulb of penis?

Answer 26

The corpora cavernosa (one corpus cavernosum either side)

Question 27

What are the corpora cavernosa?

Answer 27

Erectile chambers with overlying muscle

Question 28

What muscle overlies corpora cavernosa?

Answer 28

Ischiocavernosus muscles

Question 29

Where do the isciocavernosus muscles attach to?

Answer 29

Ischiopubic ramus

Question 30

What happens as the 2 corpora cavernosa approach the midline in males?

Answer 30

Converge at level of pubic arch and project forwards on the dorsal aspect of the penis

Question 31

What hangs from the perineal membrane in males?

Answer 31

1. Bulb of penis formed by the corpus spongiosum | 2. 2 chambers: the corpora cavernosa, covered by the ischiocavernosus muscles

Question 32

What differs in the male and female bulb?

Answer 32

Bulb in male is fused but unfused in female

Question 33

What is found either side of vaginal opening?

Answer 33

Vestibular bulbs (one bulb of vestibule either side as unfused)

Question 34

Where do vestibular bulbs hang from?

Answer 34

Perineal membrane

Question 35

What is the bulb of vestibule covered by?

Answer 35

Thin filament of muscle - bulbospongiosus

Question 36

What do the bulbs of vestibule continue forward to form?

Answer 36

Glans of clitoris

Question 37

What are vestibular bulbs formed from?

Answer 37

Corpus spongiosum tissue

Question 38

What is found lateral to vestibular bulbs?

Answer 38

Corpora cavernosa, hanging from perineal membrane, covered by ischiocavernosus muscle

Question 39

What do corpora cavernosa project forward to form in females?

Answer 39

Body of clitoris

Question 40

Where are labia majora found?

Answer 40

Either side of vaginal opening with bulb of vestibule either side

Question 41

What is found within the spermatic cord?

Answer 41

Vas deferens, testiculary artery, pampiniform plexus

Question 42

What is the pampiniform plexus?

Answer 42

Venous network that drains the testis and epipdidymis The network surrounds the testicular artery in the spermatic cord and lies anterior to the vas deferens

Question 43

What surrounds the testes?

Answer 43

Tunica vaginalis --> remnant of processus vaginalis (layer of peritoneum that invaginates during descent of testes)

Question 44

What scrotal layer comes from the transversalis fascia?

Answer 44

Internal spermatic fascia

Question 45

What scrotal layer comes from the internal oblique?

Answer 45

Cremasteric fascia

Question 46

What scrotal layer comes from the external oblique?

Answer 46

External spermatic fascia

Question 47

What scrotal layer comes from the parietal peritoneum?

Answer 47

Tunica vaginalis

Question 48

What scrotal layer comes from the transversus abdominis?

Answer 48

None

Question 49

What is the crus of the clitoris formed by?

Answer 49

The part of the corpus cavernosus attaching to the ischiopubic rami.

Question 50

What is the body of the clitoris formed by?

Answer 50

2 corpora cavernosa (right and left) projecting anteriorly.

Question 51

What part of the penis is formed from the attachment of the corpora cavernosa to the ischiopubic rami?

Answer 51

Crura