21. Perineum Flashcards
Identify the structures.
A. Pubic symphisis
B. Ischiopubic ramus
C. Coccyx: pokes in posterior aspect
D. Urogenital triangle: along ischiopubic ramus straight down (where vagina and urethra are)
E. Anal triangle (more posterior)
blue: pubic angle: formed by the 2 ischiopubic rami (angle determines whether a female or male)
green: ischial tuberosity
orange: pelvic outlet
purple: sacrotuberous ligaments
What is the alignment of the pubic tubercle?
aligned with the ASIS in the coronal plane (plane of the inguinal ligament)
Identify these structures in the female (how would it differ in males)?
A. urethral opening
B.vaginal opening
C. Anus
D. perineal membrane
E. perineal body: where perineal muscles meet
F. sacrotuberous ligaments
in males: instead of urethral opening and vaginal opening, you have the urogenital hiatus
Describe the layers of perineal pouches.
- superficial fascia
- superficial perineal pouch (where external genitalia comes out from)
- perineal membrane
- deep perineal pouch
Identify the various structures in color.
- red: superficial perineal pouch
- blue: superficial transverse perineal m (from the perineal body to ischial tuberosity and separates the anal triangle and the urogenital triangle) (more steep in male, more shallow in woman)
- purple: perineal membrane
- green: perineal body
- orange: deep perineal pouch
- yellow: ischiorectal (=ischioanal) fossae: comprises the anal triangle
What are the posterior and anterior border of the ischiorectal fossae?
posterior: gluteus maximus
anterior: superficial transverse perineal m.
Identify and describe the various structures found in the male urogenital triangle.
- blue: superficial transverse perineal m
- red: deep to superficial transverse perineal m = deep transverse perineal m (perineal body to ischial tuberosity)
- purple: perineal membrane (deep to it is the deep perineal pouch)
- yellow: external urinary sphincter: (from ischial tuberostiy and wraps around urethra)
Identify and describe the structures in the female urogenital triangle.
- blue: superficial transverse perineal m
- purple: perineal membrane
- red: deep transverse perineal m (in females: mostly made up of smooth muscle rather than striated muscles)
- yellow: external urinary sphincter (wraps around urethra)
- pink: urethrovaginal sphincter: wraps around vagina and urethra and connects to perineal body ( in deep perineal pouch)
Identify these two structures.
bottom: scrotum
top: prepuce = foreskin = extension of penis skin = acts as a protective covering for penis glands
Identify the various structures of the male external genitalia.
A. glans of penis
B. Frenulum: on dorsal aspect of penis, connect of foreskin and glans of penis
blue: corpus cavernosum splits into 2 legs from ischial tuberosity:
C. crus of penis
D. bulb of penis: where urethra enters penis through the corpus spongiosum
green: corpus spongiosum (has urethra runny through it and is softer than corpus cavernosum)
Describe the frontal view of the corpus cavernosum and corpus spongiosum.
blue: you can see the 2 legs coming together to form the corpus cavernosum
in green: corpus spongiosum with teh urethra in the middle
What do the corpus cavernosum and corpus spongiosum have in common?
they both are hollow inside to allow for blood flow to engorge tissue. They both are erectile tissue.
Identify the structures of the female external genitalia.
A. labia majora
B. labia minora
C. glans of clitoris
D. prepuce: clitoral hood
purple: urethral opening
orange: vagina
red: vestibule (main opening of vulva)
blue: corpus cavernosum (together form the glans of clitoris)
green: bulbe of vestibule (analogous to corpus spongiosum in males)
yellow: greater vestibular glands: secretes for intercourse (like the bulborethral gland in males)
Identify the various structures of the external femal genitalia.
bottom arrow: CRURA = legs of corpus cavernosum
blue: corpus cavernosum
upper arrow: glans of clitoris
green: bulb of vestibule
purple: urethral opening
orange: vagina
red: vestibule
Describe the front view of a glans of clitoris cross section
What is a clitoromegaly?clit
clitoris starts to form as penis but does not fully form = enlarged clitoris
What is a micropenis?
not fully developped penis
Name the analogous structures of the female and male external genitalia.
- glans of penis and glans of clitoris
- skin of penis & prepuce and prepuce
- penile raphe and labia minora
- scrotum and labia majora
Identify the various structures of the male ureogenital triangle.
- blue: superficial transverse perineal m
- red: deep transverse perineal m
- yellow: external urinary sphincter
- purple: perineal membrane
PART OF THE SUPERFICIAL PERINEAL POUCH:
- orange: bulbospongiosus m: (from ischial tuberosity to corpus spongiosus) wraps around shaft of penis and bulbe of penis
- green: ischiocavernosus m: (from ischial tuberosity to corpus cavernosum via ischial ramus)
Identify the various structures of the female ureogenital triangle.
- blue: superficial transverse perineal m
- red: deep transverse perineal m
- purple: perineal membrane
- yellow: external urinary sphincter
- pink: urethrovaginal sphincter
IN SUPERFICIAL PERINEAL POUCH
green: ischiocavernosus m: covers crura of clitoris
orange: bulbospongiosus m: wraps around vagina vestibule and urethra
Identify the structures in the anal triangle.
A. Levator ani muscles
B. gluteus maximums
blue: superficial transverse perineal m
red: deep transverse perineal m
green: perineal body
purple: external anal sphinctern (around anus and connects to coccyz to perineal body)
has the 2 ischiorectal fossa that is filled with fat
Describe the trajectory of the pudendal a and n.
pudendal n (S2-S4) and internal pudendal a: exits pelvis via the greater sciatic foramen inferior to the piriformis m and re-enters through the lesser sciatic foramen then goes into perineum
Identify the neurovasculature of the perineum.
C, pudendal a and n give off
A. perineal branches (for urogenital triangle: innervates external genitalia)
B.rectal branches (for anal triangle: innervates pelvic floor muscles and external urinary sphincter)
Describes the blood supply to the rectum.
- superior rectal a from IMA
- middle rectal a (goes inside pelvis) from Internal iliac a
- inferior rectal a from rectal branches off the internal pudendal a (runs along ischial spine to give off inferior rectal a)
describe the innervation of genitalia and the rectum. Explain the innervation during defacation and ejaculation.
Autonomic innervations (symp and paraymp): from inferior hypogastric plexuses (from spinal cord and caudal equina) = visceromotor nerves (above pectinate line)
Somatic innervation (under pectinate line): from rectal branches of pudendal n (because you can voluntarily control external anal sphincter)
Defacation:
- trigger: splanchnic n (visceromotor nerves) : autonomic stretch in rectum
- Urge: splanchnic n : autonomic contraction of sigmoid colon and rectum, relaxation of internal anal sphincter.
- Defamation: pudendal n : somatic relaxation of external anal sphincter and puborectalis m
Ejaculation:
- Stimulation: pudendal n: somatic sensory
- Erection: pelvic splanchnic n: parasympathetic dilation for blood flow
- emission: lumbar and sacral splanchnic n: sympathetic excretion
- ejaculation: pudendal n: somatic contraction of pelvic floor m and perineal m = orgasm
Who is the cutest bby?
My little tomato
Muuuah
I love youu
