Transcript Pelvis Forumx

Pelvis Forum
Shapes of the pelvic inlet (superior aperture)
– a. Android – heart shaped, more commonly male
– b. Anthropoid – rounded, more commonly male
– c. Gynecoid – heart-shaped, more narrow than android,
most common female
– d. Platypelloid – oval and wide, uncommon
• 2. Pelvic diameters (AKA Pelvimitry)
– a. Obstetric conjugate – top of the pubic symphysis to sacral
promontory
– b. Diagonal conjugate – bottom of pubic symphysis to sacral
promontory; can be estimated on pelvic exam
– c. True (obstetric) conjugate – back of pubic symphysis to sacral
promontory; unaffected by relaxation of pelvic ligaments
– d. Interspinous distance – between ischial spines
Pelvic + Perineum Blood Supply
Pelvic and Perineum Blood Supply
Male
Female
Nerve Supply
The ureter is in danger during:
– a. hysterectomy – it travels inferior (under) the uterine
artery “Water under the bridge”
– b. ovarectomy [ureter and ovarian vessels cross the
pelvic inlet]
Internal Iliac artery – ligation of the internal iliac artery may be
used to reduce blood flow during surgery or blockage of this
vessel may occur in atherosclerotic disease; significant
anastomoses occur between:
– a. Uterine and Ovarian (aorta)
– b. Iliolumbar/circumflex iliac and lumbar (from aorta)
– c. Lateral sacral and median sacral (aorta at division to
internal iliacs)
– d. Middle rectal and superior rectal (IMA)
– e. Inferior gluteal and profunda femoris (femoral)
Damage to the perineal body/pelvic floor - disruption of
the perineal body (episotomy) can result in dysfunction of
the muscles of the levator ani and herniation of pelvic
contents:
– a. Cystocele – collapse of the bladder into the anterior wall of
the vagina; can occur also with injury to the supportive
structures of the vagina
– b. Rectocele – anterior and inferior protrusion of the rectum
– c. Enterocele – anterior and inferior protrusion of the
rectovaginal pouch
Rupture of the male urethra:
a. Recall - the superficial fascia of the abdominal wall
(Scarpa’s) continues onto the penis and scrotum as Dartos
fascia and into the penis as Colle’s fascia and that the
deep investing fascia extends over the shaft of the penis as
Buck’s fascia and over the superificial perineal muscles
(external perineal fascia).
b. Lacerations of the spongy urethra + Buck’s fascia
intact = urine spreads along the shaft of the penis
c. Laceration of the spongy urethra + Buck’s fascia torn =
urine leaks into the superficial pouch (scrotum) along the
shaft of the penis and along the anterior abdominal wall,
deep to Scarpa’s fascia
Micturition
• Action potentials carried by sensory neurons
from stretch receptors in the urinary bladder wall
travel to the sacral segments of the spinal cord
through the pelvic nerves
– a. somatic [S2-4] – voluntary relaxation of the
sphincter urethrae
– b. sympathetics – inhibit the detrusor/excite the
internal sphincter
– c. parasympathetics – excite the detrusor/inhibit the
internal sphincter
Sacral Cord/PNS injury resulting in overflow incontinence
– i. Sensory neurogenic
– ii. Motor neurogenic/detrusor areflexia
Destruction of sacral spinal cord
– i. Autonomous bladder – continuous dribble of urine
Spinal cord injury (cervical/thoracic/lumbar)
– i. Atonic/flaccid then spastic/hyperactive
Nocturnal enuresis
– i. Abnormal changes in bladder pressure?
– ii. Delayed maturation of bladder; small bladder
– iii. Possible link to ADH secretion? Overactive detrusor
• Rupture of the spongy urethra in males in
usually the result of straddling injuries.
• Need to know the consequences of rupture to
the spongy urethrae to know where the urine
will accumulate
ANS Control of Male Sexual Response
• Autonomic control of:
– a. Erection – parasympathetic [S2-4] for vascular
smooth muscle; pudendal [S2-4] for contraction of
perineal muscles
– b. Emission – sympathetic [L1-2] for contraction of
smooth muscle in ductus deferens
– c. Ejaculation – sympathetic [L1-2] for closure of
internal urethral sphincter; parasympathteics [S2-4]
for contraction of urethral smooth muscle and
pudendal [S2-4] for contraction of perineal muscles
• Removal/ablation of the prostate endangers the
prostatic plexus which carries both sympathetic
[via hypogastric nerves] and parasympathetic
fibers [via pelvic splanchnic nerves] to the penis
• Batson’s venous plexus: many connections exist
between pelvic venous networks (e.g. prostatic)
and vertebral veins and provides a route for
metastasis of cancerous cells to the vertebral
column, skull and brain.
Uterine prolapse: protrusion of the
cervix into the vaginal – may extend
to the external orifice
signs/symptoms
Pelvic pain, lower back pain,
constipation, dysuria, painful
intercourse
results from weakness/damage to:
Pelvic diaphragm > urogenital
diaphragm > fascial ligaments
(uterosacral, transverse cervical)
peritoneal folds (e.g. broad
ligament) provide minimal support
to the uterus
Pectinate Line
• Above the pectinate line, the anal canal is visceral – autonomic
innervation (no “pain”!) and visceral support [lymph: inferior
mesenteric nodes; arterial: inferior mesenteric artery; venous: portal
system]
• b. Below the pectinate line, the anal canal is somatic – somatic
innervation (pain/touch) and somatic support [lymph: superficial
inguinal nodes; arterial: pudendal; venous: caval system]
Hemorrhoids
• a. Internal hemorrhoids: related to internal rectal plexus and
breakdown of muscularis mucosa; prolapses can result in
strangulation and/or ulceration; involves viscera and are
painless
• b. External hemorrhoids: involve the external rectal plexus;
somatic part of canal and therefore are painful!