ERS32 Anatomy Of The Male And Female Pelvis Viscera, Perineum And Breast Flashcards
Blood supply, Nervous supply of Organs in true pelvis
Main support: Pelvic diaphragm
Blood supply:
***Internal iliac artery branches
Nervous supply:
***Hypogastric plexus
(記住: 逢係比Hypogastric innervate既都係involuntary structures!!! ∵ Hypogastric —> Autonomic NS)
Pelvis sagittal section
- Urinary bladder (most anterior)
- Uterus (middle)
- Rectum (most posterior, 65% large bowel cancer, detected by Digital rectal exam, Proctosigmoidoscopy/Colonoscopy)
- **Retroperitoneal, not covered by mesentery, fixed in location
- **Ampulla (widest, most distensible)
—> 3x Transverse folds / ***Valves of Houston (help in rectal continence) (2 on left, 1 on right)
- Anal canal - Peritoneum
- cover Superior part of Bladder
- cover Anterior Rectum
- enclose Uterus
- protective layer -
**Puborectalis / Rectal sling
- part of **pelvic diaphragm, support ***Anorectal junction
- help in rectal continence - Potential space between bladder, rectum, uterus
- Male: **Rectovesical pouch
- Female: **Rectouterine pouch / Pouch of Douglas
Anatomical relationships of Rectum
Anterior:
Female: Uterus, **Rectouterine pouch
Male: Urinary bladder, **Rectovesical pouch
Posterior:
Both: Sacral bone (Sacrum), Sacral nerves, LN
Blood supply, Nerve supply, and Lymphatic drainage of Rectum
Blood supply:
1. Superior Rectal A+V (Inferior mesenteric artery) —> Inferior mesenteric vein
2. Middle Rectal A+V (Internal iliac artery) —> Internal iliac vein
3. Inferior Rectal A+V (Internal iliac artery —> Internal pudendal artery) —> Internal iliac vein
—> interconnected to form ***Rectal Anastomosis
Nerve supply:
***Hypogastric plexus (ANS)
Lymphatic drainage: 1. Pararectal nodes 2. Preaortic nodes 3. Inferior mesenteric nodes —> Intestinal trunk —> Cisterna chyli —> Thoracic duct
Spread of rectal cancer
- Posterior —> Sacral plexus (anatomical division) (severe pain)
- Anterior —> Bladder, Prostate, Seminal vesicle, Uterus, Vagina
- Lymphatics —> Involved deeper nodes —> Liver
Liver cirrhosis
Obstruction —> Portal hypertension —> blood shunted from Inferior mesenteric vein —> Rectal vein —> IVC —> ***dilatation of Rectal veins —> ***Haemorrhoids
(Inferior mesenteric vein入唔到Hepatic Portal vein)
Anal canal coronal section
高—>低
1. Rectum
-
**Anorectal junction (upper boundary)
- **Puborectalis muscle (lateral, outside rectal wall) / Rectal sling
—> **S4, S5 + **Pudendal nerve branches - Upper half of anal canal
- Anal column
- Anal sinus (space in between Anal column)
- ***Anal valve (connect lower border of columns) -
**Pectineal / Dentate line (lower boundary)
- Sphincter Ani Internus / Internal sphincter
—> Circular smooth muscles, Involuntary
—> **Inferior Hypogastric plexus (ANS i.e. involuntary) (Parasympathetic fibres) - Lower half of anal canal
- ***Ischiorectal fossa (lateral to lower half of anal canal)
—> SC fat, A+V, nerves -
**Anocutaneous line
- Sphincter Ani Externus / External sphincter (3 parts)
—> Striated muscle, Voluntary
—> **S4 (perineal branch) + ***Inferior Rectal nerve (Pudendal nerve branch) - Skin
Upper half vs Lower half Anal canal
Upper half
- Columnar (***Endoderm)
- Superior Rectal A+V
- ***Hypogastric plexus
- Pararectal LN
Lower half
- Stratified squamous (***Ectoderm)
- Inferior Rectal A+V
- ***Inferior Rectal nerve (Pudendal nerve / Somatic)
- Superficial Inguinal LN
Male Bladder, Prostate, Seminal Vesicles sagittal section
Bladder (Endoderm)
- Ureteric orifice
- Ureteric fold / ridge (connect to Ureteric orifice)
- Trigone (below Ureteric fold) (Mesoderm)
Prostate - below bladder, above Perineal membrane - base attached to bladder, apex point inferiorly (倒三角) - ***fibromuscular CT 5 lobes: 1. Anterior lobe
- Median lobe
- highly **glandular, prone to **BPH (Transitional zone), detected by digital rectal exam
—> obstruct opening of neck of bladder
—> urinary retention in bladder
—> infection within bladder (can spread to kidney via ureter) - Posterior lobe
- prone to **malignancy, **Prostatic venous plexus —> Vertebral plexus —> CNS)
- Prostatic cancer has high level of Prostatic Acid Phosphatase (∵ secretory obstruction) —> Cancer Marker - Lateral lobes x2
- Ejaculatory duct (joined by Seminal vesicle: go between Median/Posterior lobe)
- Prostatic urethra
- Perineal body
-
**Urogenital diaphragm (derived from **Deep transverse perineal muscle)
- Bladder and Prostate sit on top
Above prostate
1. ***Internal urethral sphincter (Involuntary)
Below prostate
-
**Sphincter urethrae muscle (Voluntary)
- derived from **Urogenital diaphragm (derived from ***Deep transverse perineal muscle)
Blood supply, Nerve supply, Lymphatic drainage of Prostate
Blood supply:
1. **Inferior Vesical A+V (Internal iliac artery)
2. **Middle Rectal A+V (Internal iliac artery)
—> **Prostatic venous plexus (connection with **Vertebral vein posteriorly —> tumour in prostate can spread to spine/brain)
—> Internal iliac vein
Nerve supply:
- ***Hypogastric plexus
Lymphatic drainage:
- Internal iliac nodes
Male urethra
20 cm (Female: 4 cm)
- Prostatic urethra
- traverse Prostate
- **most dilatable part
- location of **opening of ejaculatory duct - Membranous urethra
- within Urogenital diaphragm
- surrounded by **Sphincter urethrae muscle (other structures within: **Bulbourethral gland (male), **Greater vestibular gland (female))
- **most fixed, narrowed —> prone to trauma during instrumentation / accidents - Spongy (Penile / Cavernous) urethra
- longest
- pierce Corpus spongiosum (erectile tissue; Corpus cavernosum another erectile tissue)
- Urethral lacunae (opening along urethra, frequently infected by STI: Gonococcus —> may develop stricture)
—> Urethral glands (underneath)
- ***Navicular fossa (terminal dilated part)
- External urethral orifice
Urethral sphincter:
- Internal urethral sphincter (involuntary (ANS), above prostate, 喺正bladder出口)
- Sphincter urethrae muscle / External urethral sphincter (voluntary, below prostate)
- derived from ***Urogenital diaphragm
Hypogastric plexus
Sympathetic (Prevertebral ganglia):
- L1, L2 (Lumbar + Sacral splanchnic nerve)
Parasympathetic:
- S2-S4 (Pelvic splanchnic nerve)
Aortic plexus
Sympathetic (Prevertebral ganglia): T5-T11 1. Celiac ganglion 2. Superior mesenteric ganglion 3. Inferior mesenteric ganglion
Parasympathetic: Vagus nerve (mainly) + S2-S4 (via Inferior mesenteric ganglion)
Summary of Prevertebral plexus / ganglia (self-understanding)
Major
- Celiac plexus
- Celiac ganglion
- Aorticorenal ganglion - Aortic plexus (T5-T11 (sympathetic), Vagus (parasympathetic))
- Celiac ganglion
- Superior mesenteric ganglion
- Inferior mesenteric ganglion
—> T12-L2 (sympathetic)
—> S2-S4 (parasympathetic)
Minor
- Superior Hypogastric plexus
- L1-L2 (Lumbar splanchnic nerves) —> sympathetic
- S2-S4 (Pelvic splanchnic nerves) —> parasympathetic - Inferior Hypogastric plexus
- continuation of Superior Hypogastric plexus
- Sacral splanchnic nerves —> sympathetic (係L2升降機落Sacral part)
- S2-S4 (Pelvic splanchnic nerves) —> parasympathetic
Pelvic diaphragm
Lateral wall of PD: **Obturator internus
Posterior wall of PD: **Piriformis
Function of PD:
- ***Support + Stabilise Pelvic viscera at floor of pelvic cavity
- ***Sphincter for Anorectal junction (唔關anal sphincter事)+ Vagina
PD / Perineal damaged during childbearing:
Uterine / other pelvic viscera prolapse
- weakness of pelvic floor —> pelvic viscera (e.g. Uterus) protrude from pelvic diaphragm into Vagina
***Urogenital diaphragm and Pelvic diaphragm (lateral view)
- Pubic arch (anterior)
- Sacrum (posterior)
- Pelvic inlet (superior)
- Pelvic outlet (inferior)
- Urogenital diaphragm (anterior, horizontal)
- enclosed inside **Deep perineal pouch by **Perineal membrane
- connect to Pelvic diaphragm via **Perineal body (fibromuscular structure)
- transected by **Urethra, Vagina
—> ***Sphincter urethrae muscle / External urethral sphincter - Pelvic diaphragm (slightly angulated)
- **Levator ani muscle
—> **Puborectalis (part of Pubococcygeus, innermost) —> support Anorectal junction
—> Pubococcygeus
—> Iliococcygeus
- ***Coccygeus muscle
5+6 —> transects pelvic cavity at lower end
- Perineal body
- posterior to Prostate / Vagina
Upper area (extend into Pelvic inlet): True pelvic cavity
- Pelvic viscera
—> **Internal iliac artery
—> **Hypogastric plexus
Lower area (extend into Pelvic outlet): Perineum
- External genitalia
—> **Internal pudendal artery (anterior branch of Internal iliac artery)
—> **Pudendal nerve
***Urogenital diaphragm and Pelvic diaphragm (bottom view)
- Urogenital diaphragm (anterior)
- Urethra —> Sphincter urethrae muscle / External urethral sphincter
- Vagina (female) - Perineal body
- Anal canal (posterior to Perineal body)
- ***Anococcygeal raphe
- fibrous structure connecting both sides of Pelvic diaphragm
Pelvic diaphragm muscles:
- Levator ani muscle
- Puborectalis (part of Pubococcygeus, innermost) —> support Anorectal junction
- Pubococcygeus
- Iliococcygeus - Coccygeus muscle
***Nerve supply of Pelvic diaphragm
**S4-S5 + **Pudendal nerve branches
Female pelvis coronal section
Uterus (下—>上):
- Cervix
- External os
- Cervical canal
- Internal os - Body
- **Round / Proper ligament of uterus (maintain normal position of uterus)
—> pass through **Inguinal canal (lower end of Abdominal wall)
—> beneath ***Labia majora (Gubernaculum remnant stick to Labioscrotal folds) - Fundus
- Cornu (Entry point of Uterine tube into Uterus)
Other structures:
5. Ovaries
- Ureter
- beneath **Uterine artery
—> **Hysterectomy (removing uterus)
—> Accidental ligation of Ureter - Vagina
