W01: Reproductive Anatomy - Pelvis & Perineum Flashcards
Major Landmarks of the Bony Pelvis
- Sacrum (posterior)
- ASIS
- Ischial Tuberosities (sitting down)
- Ischial Spines
- Obturator Foramen: occluded by muscle
What joint type is the sacroiliac joint?
synovial diarthroid
* synovial plane: non axial
What joint type is the pubic symphysis?
secondary cartilaginous joint
Bones of the pelvis
ILIUM
PUBIS (anterior)
ISCHIUM (inferior)
What organs are associated with the iliac fossae?
Caecum, appendix (RIGHT)
Sigmoid colon (LEFT)
Arcuate Line
Divides false pelvis and the true pelvis
Differences between male and female pelvis
Male = Narrower pelvis
Female = Wider
Male = Narrow sub-pubic angle very acute but very wide and obtuse in females
Inlets:
* Male = heart shaped
* Female = oval rounded
Pelvicc Walls and roof
- OBTURATOR INTERNUS: lateral wall, true pelvis, obturator foramen = obturator canal
- PIRIFORMIS: posteiror superior wall; from the middle sacrum, passes out of the greater sciatic foramen
= both exit to join hip joint and become lateral rotators
- COCCYGEUS: posterior-inferior of the pelvic floor
What muscle ligament exits the lesser scitatic foramen?
The obturator internus’ ligament
exits out of the pelvis via the lesser sciatic foramen
Pelvic Floor
LEVATOR ANI:
1. PUBOCOCCYGEUS
- ILIOCOCCYGEUS
- PUBORECTALIS
+ Arcuate Tendon
+ Perineal body
+ Anococcygeal body
Significance of the puborectalis muscle
Wraps around the pernieal flexure of the rectum and vital in faecal continence
= creates a kink in the tract and relaxes/ flexes
What is the narrowest diameter of the pelvic inlet
antero-posteiror diameter
What is the narrowest diameter of the pelvic outlet?
transverse intraspinous diameter
Muscles of the pelvicwall cavity
OBTURATOR FASCIA: antero-lateral; look for obturator canal
piriformis: posterior wall of pelcis
coccygeus
Pelvic Floor
POST
- coccygeus
- iliococcygeus
- pubococcygeus
- puborectalis
ANT
Two functions of the pelvic diaphragm
- support abdominopelvic viscera
- resistance to increased intrapelvic pressure
- continence
What is a cystocele
Weakening of tissue of bladder and vaginal wall => collapse into cagina
Rectocele
Prolapse where supportive wall between rectum and vaginal wall
At what vertebral level does the common iliac artery divide into internal and external?
L5-S1
Obturator Art.
travels along obturator canal w/ obturator vein and nerve
- supplies the adductor region
- origin: internal iliac
Umbilliac Art.
=> superior vesical artery
- supplies the superior urinary bladder
Inferior Vescical Art
supplies lower bladder, prostate, seminal vesicle
Uterine Art
travels within cardinal ligament (lateral cervical ligament)
- crosses ureters during course
Middle Rectal Art
supplies the distal rectum
Internal Pudendal Art
Mainly supplies the perineum
Inferior Gluteal Art.
Terminal branch of the internal iliac artery
Significance of the Gonadal Arteries
RESPECTIVELY, THE OVARIAN AND TESTICULAR ARTERIES supply ovaries and testicles and arise from the ABDOMINAL AORTA just inferior to insertion of renal arteries into the kidneys
- testicular artery travels via inguinal canal via deep inguinal ring
Which part of the rectum drains into the portal circulation?
superior rectal vein => inferior mesenteric vein
Which part of the rectum drains into the systemic circulation?
Inferior and middle veins
Significance of the communications of the prostatic venous plexus?
Communicates with vertebral venous plexus thus significant for mets spread
ilioinguinal nerve
originates L1
superficial inguinal ring
=> skin root penus, labia
genitofemoral nerve
L1-2
deep inguinal ring
> scrotal skin, cromaster muscle
Pudendal nerve
arises form sacral plexus (S2-S4)
- follows pudendal artery
- pudendal canal (also known as Alcock’s canal – a structure formed by the fascia of the obturator internus muscle)
> skin and muscles of perineum
Motor – innervates various pelvic muscles, the external urethral sphincter and the external anal sphincter.
divisions of the pudendal nerve
giving off the inferior rectal nerve, then the perineal nerve, before continuing as the dorsal nerve of the penis or clitoris.
Perineal Nerve
(pudendal)
innervates bulbospongious, ischiocavernous, levator ani,
innervates the external urethral sphincter
Therefore, the pudendal nerve provides the voluntary/somatic control of faecal and urinary continence.
Sensory innervation of external genitalia
Inferior rectal nerve – the perianal skin ,lower third of the anal canal.
Perineal nerve – the skin of the perineum, labia minora and majora or posterior scrotum.
Dorsal nerve of the penis or clitoris – the skin of the penis or clitoris. Thus, responsible for the afferent component of penile and clitoral erection.
Bony landmark significant for pudendal nerve block
ischial spine
autonomic nerve supply of pelvis
pelvic plexus
sympathetic = L1, L2 = hypogastric nerve and terminal aspect of symp. trunk
parasymp = pelvic splanchnic nerves (S2 - S4)
erectile tissues
What is damaged in rectal surgeyr resulting in dysfunctional ejaculation in men?
Autonomic sympathetic nervous system (hypogastirc nerve)
Lymphatic drainage of pelvis
EXT. ILIAC LN =
> ANTEROSUPERIOR PELVIC
INTERNAL ILIAC LN
> gluteal region, deep perineum, inferior pelvic viscera
SACRAL LN
> postero. viscera
LUMBAR LN
> drainage from three main groups
