Perineum Flashcards
Definition of the perineum
Part of the lesser pelvis that contains the external genitalia
Parts: urogenital triangle, anal triangle
shallow, narrow compartment
inferior to the pelvic floor muscles/fascia
supports openings from the pelvic floor
Boundaries of the perineum
pubic symphysis
ischiopubic rami
ischial tuberosities
sacrotuberous ligament
coccyx
What does the perineum include?
the genitals, external urinary and the anus
urogenital triangle openings
openings for urinary and genital systems
anal triangle
openings for the anus
Mons pubis def:
he mons pubis, also known as the mons Venus or pubic mound, is the rounded mass of fatty tissue that lies over the pubic bones
What are the components of the female vulva?
mons pubis
labia minora
labia majora
clitoris
vaginal opening
urethral opening
The function of the perineal body
the intersection of many structures/an anchoring structure
-provides attachment to various muscles
-strengthens the pelvic floor
Stress incontinence def and causes;
small vol. leakage of urine with coughing, sneezing, exercise
due to lack of endurance in perineal muscles, not power
poor urethral support from pelvic floor muscles; continuous dripping can occur from incomplete closure of urethra due to atrophy or post-surgical changes
Risk factors for urinary incontinence
pregnancy and postpartum
vaginal delivery
forceps delivery
increased parity
increased BMI
operative trauma and scarring of the urethra
Where are the internal pudendal artery and vein in relation to the ischial tuberosity?
medial
What do the inferior rectal artery and vein supply?
the external anal sphincter
Cutaneous innervation of the perineum comes from what 4 nerves:
ilioinguinal n.
genitofemoral n.
pudendal n.
posterior femoral cutaneous n.
posterior femoral cutaneous nerve functions:
GLUTEAL BRANCHES: function- sensory & postganglionic sympathetic innervation of skin overlying part of the gluteus maximus
PERINEAL BRANCHES: function- sensory & postganglionic sympathetic innervation of skin overlying part of the posterior aspect of the perineum
pudendal nerve (S2-4) - inferior rectal nerve functions
sensory & postganglionic sympathetic innervation of the skin overlying the anus; sensory, postganglionic sympathetic & motor (lmn) innervation of the external anal sphincter—> excretion of feces
pudendal nerve (S2-4) - perineal nerve
MUSCULAR BRANCHES– sensory, postganglionic sympathetic innervation of the corpus spongiosum or bulb of the vestibule; sensory & postganglionic sympathetic innervation of the spongy urethra; sensory, postganglionic sympathetic & motor (lmn) innervation of the perineal muscles
POSTERIOR LABIAL OR SCROTAL BRANCHES- function- sensory & postganglionic sympathetic innervation of the skin overlying the labia majora & minora, lower vagina & urethra or scrotum
DORSAL NERVE OF THE CLITORIS OR PENIS- sensory & postganglionic sympathetic innervation of the skin overlying penis or clitoris; sensory, postganglionic sympathetic innervation to the corpus cavernosum
Ilioinguinal nerve (LUMBAR PLEXUS - L1) function:
sensory & postganglionic sympathetic innervation of skin overlying proximal medial thigh, the root of the penis & scrotum or mons pubis & labia majora; sensory, postganglionic sympathetic & motor (lmn) innervation of muscles of the anterior abdominal wall
Genitofemoral nerve (L1-L2- lumbar plexus) function:
GENITAL BRANCH
function- sensory & postganglionic sympathetic innervation of the skin overlying part of the labia majora or scrotum; sensory, postganglionic sympathetic & motor (lmn) innervation of the cremaster muscle
FEMORAL BRANCH
function- sensory & postganglionic sympathetic innervation of skin overlying the femoral triangle
What comprises the female erectile tissue?
glans of clitoris
vestibular bulb - covered by bulbospongiosus in the labia majora
crus of clitoris - covered by ischiocavernosus
Ischioanal fossa
-fat pads and loose connective tissue
found in the anal triangle and fat pads offers support to the rectum, preventing prolapse; outside of the rectum and extends anteriorly to go on the lateral aspect of the vagina
CONTENTS:
-pudendal canal: internal pudendal artery, pudendal nerve
-outside canal: inferior rectal artery, inferior rectal nerve
Ischioanal abscess in ischioanal fossa:
infection, collection of pus
anal sinus inflammation
anal membrane tear (feces)
anal penetrating wound
there is a meet up between the two ischioanal sinuses posteriorly–> can spread infection
Composition of male external genitalia:
distal urethra
penis
scrotum
all within the urogenital triangle
what is the enlargement of the corpus spongiosum?
the bulb of the penis
What transitions into the glans of the penis (distal enlargement) if followed distally?
corpus spongiosum
What flares out into the crus of the penis more proximally?
the corpus cavernosum
What is the name of the deep fascia of the scrotum?
tunica dartos
Cremaster attachments, actions, innervation
attachment- from the medial edge of the internal oblique to spermatic cord
actions- elevation of testis
innervation- genitofemoral nerve
What is the first layer of the fascia that wraps around spermatic cord?
external spermatic fascia
What coverings cover the testis?
tunica vaginalis parietal and visceral layer–> covering of testis
What foramen does the internal pudendal artery leave through?
the greater sciatic foramen, and then comes in through the lesser sciatic foramen to approach the perineum
Pudendal nerve course and branches
descends vertically through sciatic foramina (around pelvic floor) –> leave GSF, come back in through LSF
FUNCTIONS:
-micturition (urination)
-defecation (feces)
-parturition (childbirth)
-erection
-ejaculation
Pudendal nerve function in erection and ejaculation:
ERECTION - POINT - parasympathetic
-smooth muscles of corpora cavernosa relax (para.
axons hitch-hiking on ventral rami S2-4 as they come out of the spinal cord; cavernous nn. extensions of prostatic plexus)
EJACULATION- SHOOT - sympathetic
-contraction of internal genital organs (sympathetic L1-2; lumbar splanchnic to hypogastric plexus
What forms where the adjacent anal columns meet?
the anal sinuses
What is the nonvoluntary, autonomic opening of the anus?
The internal anal sphincter
What is the voluntary, somatic opening of the anus?
external anal sphincter
deep part, superficial part, subcutaneous part
What muscle(s) are considered the pelvic diaphragm?
the levator ani muscles and coccygeus
Where do we transition from rectum to anus?
where the levator ani comes around the terminal portion of the digestive system
