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%+
Testicular torsion
Sudden onset scrotal swelling and pain
Testis spins on axis, compromising blood supply, -> gangrene
EMERGENCY
Anterior pituitary
Upgrowth of oral cavity (Rathke’s pouch)
Glandular epithelium, secrete small protein/glycoprotein hormones
Acidophils - orange staining, 70% cells, including somatotrophs (GH) and lactotrophs (prolactin)
Basophils - red staining, including corticotrophs (ACTH), gonadotrophs (LH, FSH) and thyrotrophs (TSH)
Cells controlled by hypothalamic hormones (releasing or inhibiting)
Pars distalis (main part), pars intermedia, pars tuberalis (collar and stalk)
Posterior pituitary
Downgrowth of diencephalon
Pars nervosa - axons and terminals of hypothalamic neurosecretory cells (cell bodies in hypothalamus)
Vasopressin and oxytocin secreted here and stored in Herring bodies
Pituicytes also found here - type of glial cell, irregular shape, rounded/ovoid nuclei
Adrenal gland layers
Zona glomerulosa
- small columnar/pyramidial cells
- rounded nuclei
- numerous sinusoidal capillaries around
- in clusters, then columns
- secrete mineralocorticoids
Zona fasciculata
- large polyhedral cells
- small central spherical nuclei
- cells in straight cords
- surrounded by fenestrated sinusoidal capillaries
- secrete mainly glucocorticoids, some weak androgen
Zona reticularis
- smaller cells
- arranged in anastamosing cords -> net-like appearance
- secrete mainly weak androgens, some glucocorticoids
Medulla
- chromaffin and ganglion cells, surrounded by sinusoidal capillaries and nerve fibres
- chromaffins secrete catecholamine hormones
Ducts of testes
Seminiferous tubules
Rete testis
Ductus efferens
- 95% fluid reabsorbed here
- pseudostratified epithelium -> saw-tooth appearance
- fine basement membrane, thin layer circular smooth muscle
Ductus epidiymis
- single convuluted tubule
- pseudostratified columnar epithelium
- tall principal cells - even surface, long stereocilia, then shorter in tail of epididymis
- thin circular muscle layer, thickens near deferens
Ductus deferens
- thick walled, muscular tube
- widens to form ampulla, joined by ducts of seminal vesicles
Ejaculatory duct
- enters prostatic urethra
- less tall columnar or pseudostratified epithelia
- short microvilli mat together to form cones
- dense lamina propria, several longitudinal folds
Spermatogenesis
Type A dark spermatagonia - resident stem cells, resting on basement membrane
Type A light spermatagonia - regularly dividing
Type B spermatagonia
Primary spermatocyte - larger, further out than 2º
Secondary spermatocyte - rare to see, differentiate quickly
Spermatid
Sertoli cells span width of seminiferous tubule
Prostate gland
30-50 tubulo-alveolar glands arranged in layers, surrounded by smooth muscle and connective tissue
3 glands open into urethra:
MUCOSAL
- in peri-urethral tissue
- contribute little to secretions, but enlarge in prostatism
- empty directly to urethra
SUBMUCOSAL
- peripheral to mucosal glands
- drain into prostatic ducts that open at urethral sinus
MAIN
- 70% secretions from here
- in largest, outermost portion
- susceptible to inflammation, site of carcinomas
- drain into prostatic ducts that open at urethral sinus
Alveoli (folded simple columnar epithelia) of glands surrounded by stroma, and concretions (calcified deposition in older men)
Follicles of ovary
Primordial
- declining pool formed before birth
- in superficial layers of cortex
- primary oocyte surrounded by flattened granulosa cells on basement membrane
Primary
- develop spontaneously
- deeper in cortex
- oocyte enlarged, zona pellucida present, cuboidal granulosa in several layers, theca interna beginning to form
Secondary (= Graafian)
- formed by FSH stimulation at start of cycle
- granulosa 6 layers thick, antrum of follicular fluid, oocyte at edge
Tertiary
- only one formed per cycle, after LH surge
- ovulated after 12-24 hours
(atretic follicles also)
Ovary
Almond shaped, 3cmx2cmx1cm (shrivels at menopause)
Attached to broad ligament by mesovarium Round ligament (formed from gubernaculum) joins ovary to fundus of uterus and then continues through inguinal canal to labium major Suspensory ligament contains blood vessels, travels from pelvic wall to mesovarium
Ovarian arteries (from AA at L1) supply
Ovarian veins drain (left to left renal vein, right to IVC)
Lymph to para-aortic nodes
-> to produce oocytes, and oestrogen + progesterone
Oviducts
10cm long, enclosed by broad ligament except at distal ends
Four parts:
- intramural
- isthmus
- ampulla
- infundibulum
Ciliated columnar epithelia and peg cells line
Branches of ovarian and uterine arteries supply
Corresponding veins drain
Lymph to para-aortic and internal iliac nodes
Inner mucosa -> waft ovum to uterus, supply it with nutrients
Smooth muscle layer -> peristalsis of ova/sperm (increased in high oestrogen)
Uterus
Anteverted at vagina, anteflexed at cervix
Enclosed in broad ligamnet - the perimetrium is part of the broad ligament adherent to uterus
Uterine artery supplies (runs in broad ligament)
Plexus in broad ligament drain to uterine veins
Lymph: fundus to para-aortic, body + cervix to internal/external iliac nodes
Broad ligament
Fold of peritoneum from lateral walls, across pelvic cavity
Encloses uterus and oviducts
Ovaries attached to posterior aspect
Lateral attachments form the suspensory ligaments of the ovary
-> forms the utero-vesical and recto-uterine pouches
(RU pouch = pouch of Douglas, fluid may collect here)
Endopelvic fascia
Surrounds nerves and vessels in pelvis
Thickenings form uterine ligaments:
- uterosacral - to sacrum
- transverse cervical (cardinal) - to lateral walls
- pubo-cervical - to body of pubis
Continues downwards to form recto-vaginal septum
Ligaments necessary to hold cervix in place and (with pelvic diaphragm) support the uterus. Weakening of these ligaments can -> uterine prolapse
Vagina
Stratified squamous epithelia, lubricated by cervical mucus
Vaginal artery (from internal iliac) supplies, and the vaginal branch of the uterine artery
Vaginal venous plexus drains to internal iliac
Upper 1/3 lymph -> iliac nodes, middle 1/3 -> internal iliac nodes, lower 1/3 -> superficial inguinal nodes
Testis
Coverings:
- tunica albuginea - tough fibrous capsule
- tunica vaginalis - only anterior, medial, lateral surfaces
- internal spermatic fascia
- cremasteric fascia
- external spermatic fascia
Testicular arteries (from AA at L1) supply
Pampiniform plexus drains to testicular vein, left to left renal, right to IVC
Lymph to para-aortic nodes
Testicular plexus from T10 supplies nerves
Spermatic cord
3 coverings:
- internal spermatic fascia - from transversalis fascia
- cremasteric muscle and fascia - from internal oblique
- external spermatic fascia - from aponeurosis of external oblique
3 arteries:
- testicular artery
- artery to vas deferens
- cremasteric artery
3 nerves:
- ilioinguinal
- T10
- genital branch of genitofemoral
3 others:
- pampiniform plexus
- vas deferens (most prominent)
- lymph vessels
Prostate, seminal vesicles and bulbourethral gland
PROSTATE
Responsible for 30% seminal fluid
Fibromuscular and glandular parts
Prostatic arteries supply (from inferior vesical artery)
Prostatic venous plexus drains to internal iliac
Lymph to internal iliac nodes
SEMINAL VESICLES
70% seminal fluid
5cm long coiled tubular glands
Between bladder fundus and rectum
BULBOURETHRAL
Make pre-ejaculate
Found within fibres of external urethral sphincter (don’t drain to ejaculatory duct)
Testicular descent
After 7th gestational month
Necessary, testes need to be 2º cooler
CRYPTORCHIDISM = undescended testes
1% children
Get caught on deep/superficial inguinal rings -> abdominal/inguinal testes
If caught lower down -> suprascrotal, may be ‘milked’ down
Increased risk of infertility and testicular cancer
Erection and ejaculation
Point and shoot
Parasympathetic and Sympathetic control
Erectile dysfunction
Inability to achieve or maintain an erection to sufficiently satisfy sexual intercourse
Causes:
In the young, often psychogenic (nervousness)
In 50+:
- vascular (cholesterol, smoking, diabetes)
- neurogenic (after prostate surgery)
- drug-induced (anti-depressants, anti-hypertensives)
- hormonal (rare - hypogonadism)
Treat with psychosexual therapy, viagra/sildenafil, topical prostaglandin, stop cause!
Ectopic pregnancy
Sudden onset (right iliac fossa) pain -\> rupture of embryonic sac in right fallopian tube - consider appendicitis!
Should be implantation in fundus or body of uterus
- 80% ampulla
- 12% isthmus
- 5% fimbriae
- abdominal
- cervical
11/1,000 pregnancies
Increased risk from IVF, pelvic inflammatory disease, endometriosis, surgery, IUD, previous ectopic pregnancy
Laparoscopy
= key hole surgery
3 (or 5) 1-2cm incisions
Scope in at umbilicus, other instruments elsewhere
Insert instrument to cervix to get uterus in right position
Diagnostic or therapeutic (ovarian torsion, ectopic pregnancy, endometriosis)
