Endo/Repro anatomy Flashcards
Internal iliac artery branches
Divides to
Posterior:
iliolumbar (p), lateral sacral (p) and superior gluteal (p)
Anterior: inferior gluteal (p) umbilical, obturator (p), inferior vesical/vaginal, middle rectal, internal pudendal (p)
(p) = parietal, rest are visceral
Corresponding veins form plexuses around viscera and drain to internal iliac vein
Obturator internus, piriformis, levator ani and coccygeus roots and actions
Obturator internus + piriformis
- S1-2
- abduction and external rotation of leg, stabilising hip joint
Levator ani + coccygeus
- S3-5
- urinary control, support of pelvic organs
Pelvic fractures
Range in severity - can be life-threatening
Pelvis is ring, so if break in one place then likely to be other breaks (but takes force to break!)
Rich plexus of veins and arteries, so if damaged then catastrophic bleeding
Perineum
Between pelvic outlet and pelvic diaphragm
Urogenital triangle
- ischial tuberosities to pubic symphysis
- contains external genitalia
Anal triangle
- ischial tuberosities to coccyx
- contains anus
Perineal membrane is between inferior pubic rami (so only covers urogenital triangle)
- external genitals attach to
- perineal body is fibromuscular node between anal and urogenital openings - join of levator ani, bulbus spongiosum, external anal sphincter, transverse perineal muscles to perineal membrane
- anococcygeal body is fibromuscular join of levator ani fibres converging and joining to coccyx
Ischioanal fossa
Between levator ani (sloping roof) and obturator internus (lateral wall)
Pudendal canal runs through - containing internal pudendal vein and artery, pudendal nerve
Fat filled space
Allows movement of pelvic diaphragm and expansion of anal canal during defecation
Pelvic fascia + deep and superficial perineal pouches
Abdomen
– peritoneum –
Pelvic cavity
– levator ani, piriformis (pelvic floor) –
Deep perineal pouch
– perineal membrane (only at urogenital triangle) –
Superficial perineal pouch
– labia/skin –
DEEP PERINEAL POUCH
Contents of urogenital triangle lying superior to perineal membrane
Contain bulbourethral glands in men
SUPERFICIAL PERINEAL POUCH
Contents of urogenital triangle lying inferior to perineal membrane
Contains erectile bodies - ischiocavernosus, bulbospongiosus, superficial transverse perineal muscles + vestibular glands in female
Pudendal nerve
S2-4
Sensation to penis/clitoris, posterior scrotum/labia, anal canal
Motor to bulbospongiosus and ischiocavernosus (sexual function), levator ani, external anal sphincter, external urethral sphincter, transverse perineal muscles
Leaves pelvis by greater sciatic foramen and then re-enters by lesser sciatic foramen
Male vs female pelvis
MALE
- heart shaped pelvic inlet
- 0 taller pelvic outlet
- deeper pelvic cavity
- less than 90º pubic arch angle
- longer sacrum and coccyx
- > primed for walking
FEMALE
- O transverse wider pelvic inlet
- 0 taller pelvic outlet (so baby rotates in birth)
- shallower pelvic cavity
- greater than 90º pubic arch
- shorter flatter sacrum, shorter moveable coccyx
- > primed for walking + childbirth
(in pregnancy, relaxin hormone increases diameter of pubic symphysis and sacroiliac joints, so wider pelvis)
Episiotomy
Mediolateral (always now, to divert tear from anus) or midline (easier to perform, faster healing, better cosmetics)
To prevent damage to pelvic floor, as would effect continence especially if tear into anus
- cut through skin, bulbospongiosum, superior transverse perineal + levator ani if necessary
Can be no anaesthetic if emergency, or do pudendal nerve block (usually for forceps birth)
Complications -> haematomas, oversewing of pouch so vagina too small, (rare) fistula between vagina and rectum
Female external genitalia
Mons pubis (fat filled, covered in pubic hair)
Vulva, inc clitoris
Labia majora (analagous to male scrotum) and minora (come together to form clitoral hood)
Vestibule - contains external urethral meatus, vaginal orifice (vestibular glands secrete lubrication here)
Clitoris
Anatomically analogous to male penis
Erectile tissue is crura and bulb of vestibule
Glans partially covered by prepuce (labia menora fold hood)
- Internal pudendal artery supplies
- Dorsal veins drain to internal pudendal vein
- Lymph to medial superficial inguinal nodes
- Somatic nerve supply from pudendal nerve
Penis
Three masses of erectile tissues:
CORPORA CAVERNOSA
- crura are legs, proximal attachment to ischial rami, ischiocavernosus constricts
- shaft
- – deep artery of penis supplies (cavernosal arteries)
CORPUS SPONGIOSUM
- bulb - attached to perineal membrane, bulbospongiosus constricts to stabilise erection, propel urethral contents in ejaculation and urination
- shaft (surrounding urethra)
GLANS
— bulbourethral artery supplies CS and glans
Arteries both branches of internal pudendal
Corresponding venous drainage to internal iliac veins
Skin -> superior inguinal lymph nodes, glans -> deep inguinal nodes and external iliac nodes
Male urethra
Prostate gland and seminal vesicles empty into ejaculatory duct, bulbourethral gland empties near bulb of penis to penile urethra
1 - pre-prostatic
2 - prostatic
3 - membranous/intermediate
4 - spongy/bulbar
Scrotum
Contains testis and its coverings
Skin is pigmented and rugosae
Subcutaneous tissue
Dartos muscle - to move testicles up into body in cold temperatures
Lymph drains to superficial inguinal nodes
Testicular cancer
Painless swelling, enlarged testicle
7/100,000 prevalence, lifetime risk of 1/200
Most common aged 15-35
Risk factors - testicular maldescent, infantile hernia, XXY Klinefelter’s syndrome, family history, infertility, tall height
Tumour would spread to para-aortic lymph nodes (in abdomen)
Good prognosis if caught early - 5 year survival 90%+