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pelvic floor layers
- muscles and membranes which separate pelvic cavity and perineum
- levator ani
- coccygeus
- deep perineal pouch
- perineal membrane
-
perineum
- region inferior to the plevic floor containing external anatomy of urinary, GIT and reproductive systems
- divided into urogenital and anal triangles
-
corners, contents of urogenital triangle
- both ischial tuberosities, pubic symphysis
- roots and openings of external genitalia
-
corners, contents of anal triangle
- both ischial tuberosities, coccyx
- anal aperture
-
musculofascial pouch of scrotum
- external spermatic fascia
- cremasteric fascia
- internal spermatic fascia
continuations of external and internal oblique, tranversus abdominis aponeuroses and transversalis fascia
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dartos vs cremaster
- dartos: slow contraction decreasing scrotal SA to reduce heat loss in cold environment; continuation of scarpa
- cremaster: fast reflex contraction (L2 femoral branch of genitofemoral N) to raise testicles in response to cold; continuation of conjoint tendon from fusion of internal oblique and transversus abdominis
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tunica vaginalis vs. albuginea
- vaginalis: remnant of processus vaginalis, double peritoneal membrane surrounding anterior and lateral aspects of testes
- albuginea: thick connective tissue capsule around spermatogenesis tissues, vascular interstitium and epidydimis
-
spermatogenesis tissues
sertoli cells form semifinerous tubules, sites of spermatogenesis, which are supported by leydig cells
-
pathway of sperm
- seminiferous tubules
- straight tubules
- retes testis
- efferent ductules
- epididymis (true>tail)
- ductus deferens
- ampulla
- ejaculatory ducts
- prostatic urethra
- membraneous urethra
- spongy/penile urethra
- external urethral orifice
-
ductus deferens path
- tunica vaginalis: medial aspect of testis within
- spermatic cord: ascends within
- inguinal canal: superficial inguinal ring and out through deep inguinal ring
- anterior abdominal wall: perforates anterior peritoneum lateraly to inf epigastric artery and bends medially around side of it
-
lymphatic drainage gonads
- lateral aortic aka lumbar nodes: inferior to IMA and on lateral aspect of aorta
- preaortic: between SMA and IMA on anterior aspect of aorta
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important features of uterine artery
- arises from anterior trunk of internal iliac artery
- crosses over ureter as it travels medially on the posterior abdominal wall in the base of the broad ligament
- ascends from lateral fornix of cervix along lateral wall of uterus and anastomoses with ovarian artery
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blood supply of the rectum
- superior, middle and inferior rectal arteries
- superior: IMA
- middle: IIA
- inferior: IPA
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branches of internal iliac artery
- posterior trunk (3): iliolumbar, lateral sacral, superior gluteal
- anterior trunk (6): inferior gluteal, internal pudendal, middle rectal, inferior vesical/uterine/vaginal, obturator, superior vesical
-
anatomical basis of haemorrhoids
submucosal venous plexus, anastomoses of superior rectal veins (from IMV, draining into portal vein) with middle and inferior rectal veins in anal column submucosa become engorged and rupture
-
pectinate line of anal canal
- separation of mucosa
- upper part: anal columns and valves with columnar epithelium sensitive to liquid/gas/solid but not to pain
- lower part: stratified squamous epithelium extremely sensitive to pain
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anal sphincters
- internal anal sphincter: involuntary, circular SM, SNS innervation by inf hypogastric plexus, upper 2/3 only
- external anal sphincter: voluntary, longitudinal striated, inf rectal N of pudendal nerve (S2-4)
- puborectalis muscle: part of levator ani muscles that reinforce perineal apertures, pudendal nerve (relaxation straightens anorectal angle)
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nervous control defecation
- inf hypogastric plexus (PNS): relaxation internal anal sphincter
- thoracic spinal N: contraction abdo Ms
- phrenic N: elevate diaphragm
- vagus N: close larnyx
- inf rectal N (pudendal): relaxation of ext anal sphincter, puborectalis
- inf hypogastric plexus: peristalsis rectal Ms
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pudendal N origin and branches
- S2-S4 of sacral plexus
- inf rectal N: external sphincters, levator ani (motor to anal triangle)
- perineal N: motor and sensory to urogenital triangle
- dorsal N of penis/clit: sensory
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borders of ischioanal fossa
- pyramidal shape with opening of fossa posteriorly
- laterally: obturator internus
- superiorly: levator ani
- medially: anal canal
- inferiorly: perineal membrane
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sacroiliac joint type
- anteriorly synovial
- posteriorly fibrous
-
broad ligament and contents
- peritoneal fold over fundus and body of uterus forming double layer
- uterine tubes
- uterine artery
- round ligament of uterus
- part of ureter
-
secondaries to the broad ligament
- mesovarium: part suspending ovary to broad ligament
- mesosalpinx: part between uterine tubes and and origin of mesovarium
- mesometrium: broad ligament excluding mesovarium and mesosalpinx
-
ligaments of ovary
- suspensory: peritoneal fold connecting ovary to lateral pelvic wall containing ovarian vessels and nerve plexus
- mesovarium: part of broad ligament suspending ovary to broad ligament
- ligament of ovary: fibromuscular band suspending ovary to uterus
-
path of ovarian vessels
branches of main vessels, descend along posterior abdominal wall along psoas major, crossing over external iliac vessels at pelvic brim and course medially within suspensory ligament towards ovary
-
arrangement of gonadal veins
pampiniform plexus surrounding corresponding artery
-
round ligament
- remnant of gubernaculum which guides path for testicular descent in males
- fibromuscular band beginning at lower pole of ovary connecting it to the uterus (ligament of ovary)
- from uterus passes over pelvic inlet, goes through inguinal canal
- terminates at connective tissue of labium majus in perineum
-
uterus nerve supply
sympathetic afferent fibres at L1 level: lower abdomen
-
uterus positions
- normally anteverted (vag/cer angle) and anteflexed (cervix/uterus)
- 20% born with retroverted which can be associated with dyspareunia or dysmenorrhea or problems during pregnancy
-
consequences of urinary obstruction
- hypertrophy of detrusor muscle forming a thickwalled trabeculated bladder
- risk of mucosal outpouchings between muscle bands to form bladder diverticula
-
bladder wall layers and cancer risk factors
- mucosa: transitional epithelium, most likely site of carcinoma
- submucosa: lamina propria
- muscle: three layered detrusor muscle of different orientations
- serosa: visceral peritoneum
-
spinal cord features
- spinal nerves: C8 T12 L5 S5
- cervical enlargement: C5-T2
- brachial plexus: C5-T1
- conus medullaris: termination of spinal cord proper at L2
- subarachnoid termination: S2
- filum terminale: termination of cauda equina within dura (not subarachnoid space)
-
veru montanum
seminal colliculus, dilated internal membrane of prostatic urethra within urethral crest into which blind ended pouch prostatic utricle and ejaculatory ducts open
-
bends and narrowings in male urethra
- preprostatic urethra: narrowing - internal urethral sphincter at bladder neck
- membraneous urethra: bend and narrowing - at exit from deep perineal pouch, narrowest part of urethra formed by external urethral sphincter
- spongy urethra: bend when flaccid
- external urethral meatus: narrowing
-
what does the term water under the bridge refer to in pelvic anatomy
path of ureter beneath ductus deferens in males and uterine arteries in females
-
parts of vagina
- introitus: opening in perineum
- vaginal vault: body of vagina
- vaginal fornices: anterior, posterior and lateral recesses around cervix
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