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Clinical Correlations: Pelvis & Perineum Blue Boxes from Moore's
Clinically significant details about pelvis and perineum
Terms in this set (57)
Pierce the sacrococcygeal ligament
Trans-sacral epidural anesthesia is given through the sacral hiatus, penetrates the dural sac. Must palpate for the hiatus by locating the sacral cornua
Most suitable pelvis for delivery
Gynecoid; has ovoid inlet, large transverse diameter, cylindrical cavity, large outlet, subpubic angle > 90°
Anteroposterior diameter. Determine if the inlet is adequate for delivery of fetus
How to measure obstetric/true conjugate
Palpate for the sacral promontory with middle finger, measure the length to the pubic symphysis. Subtract 1.5 cm to obtain true conjugate, the shortest distance btw pelvic surface of symphysis and sacral promontory
Measure pelvic outlet for adequate space for delivery
Ischial tuberosities permit 4 knuckles between them
Measure subpubic angle for adequate space for delivery
Three fingers can enter vagina side by side
Pudendal nerve block
Administer at ischial spine, one side needed in order to perform an episiotomy.
Physician's finger must be in vagina between baby's head and needle tip.
Fetal head is larger than the mother's pelvis; an example is hydrocephaly and a normal pelvis. Dangerous for mother and fetus
- A/P compression
- Lateral compression
- Fractures to bony pelvic ring
- Due to a crush accident, commonly fractures pubic rami
- Acetabula and ilia can fracture
- Multiple fractures and joint dislocation occur
Weak areas of pelvis
Pubic ramus, acetabulum, sacroiliac joint, ala of ilium
"Open book" pelvis fracture
Pubis separates at the symphysis
Injury to pubo-obturator area may rupture bladder and urethra
Fracture to acetabulum
Due to a fall on feet or buttocks, can injure nerves, vessels, pelvic viscera. Under 17 y.o. may fracture through the triradiate cartilage into three acetabular margins
Interferes with parturition; L5 vertebra narrows the pelvic cavity, compresses spinal nerves and causes low back pain
Test by running fingers along lumbar spinous processes
1st structure to be damaged in anteroinferior pelvic wall
Bladder; wall consists of pubic bodies and rami, pubic symphysis
Most dependent pelvic fossa in males
Recto-uterine pouch (of Douglas)
Most dependent pelvic fossa in females
Make an opening to drain bladder that has become obstructed. Example is BHP in prostate
Injury to pelvic floor
Pubococcygeus, puborectalis often torn during birth
Urinary stress incontinence
Urine dribbles when intra-abdominal pressure increases. Leads to prolapse of pelvic organs: Uterus may descend into vagina, fecal incontinence
Prolapse of pelvic viscera
Bladder prolapses through urethra
Uterus/vagina prolapses through vaginal orifice
Perineal body injury
Due to trauma, inflammatory disease, may form a fistula, abnormal canal connected to the vestibule
Diastasis associated with it (separation of puborectalis and pubococcygeus) --> can form herniations:
- Cystocele - posterior wall of bladder into anterior wall of vagina - issues w/ micturation
- Rectocele - rectum herniates in to vagina
- Enterocele - rectovaginal pouch protrudes into vagina
Vaginal surgery and labor; a surgical incision of perineum and inferoposterior vaginal wall. Orifice is enlarged to decrease traumatic tearing of perineal muscles
Further tearing can damage external anal sphincter, lead to anovaginal fistulae, incontinence.
Initially median, then turns posteriorly to avoid further tearing of anus
Ruptured urethra and extravasation
Males, due to fracture of pelvic girdle, separation of pubic symphysis, puboprostatic ligaments, can rupture intermediate urethra
- Results in extravasation of urine and blood into deep perineal pouch
- Fluid passes superiorly thru UG hiatus, around prostate and bladder.
Blow to perineum, rupture to bulbar urethra, corpus spongiosum, spongy urethra. Urine enters superficial perineal space
- further extravasation of urine into scrotum, penis, inferior anterior abdominal wall.
- Perineal fascia prevent spread to anal triangle.
- Membranous layer of sup perineal fascia prevents spread to the thighs.
Ilioinguinal nerve block
Numbs sensation from anterior perineum (anterior scrotal, anterior labial nerve)
Inject just before nerve enters canal (midinguinal point)
- 2 in medial and 2 in down from ASIS
If pain exists after ilioinguinal and pudendal nerve blocks, it is usually due to overlapping innervation of perineal branch at posterior cutaneous nerve of thigh
Umbilical artery exchange transfusion
Rh incompatibility - must take out some fetal blood and add some new. Cannot volume overload the fetus.
Injury to pelvic nerves
Sacral plexuses can be compressed during childbirth
Obturator nerve can be injured in surgery (ex is lymph node removal from lateral pelvic wall), causes painful spasm of adductors, loss of sensation to medial thigh.
Starvation causes loss of fatty tissue, ischioanal fat, commonly leads to rectal prolapse
Dentate line/pectinate pain line
Serrated line following anal valves and crossing bases of the anal columns. Demarcates visceral from somatic parts of anal canal.
Lymph above: internal iliac lymph nodes, below: superficial inguinal.
Venous drainage above: portal system, below: caval.
Internal hemorrhoids/piles above, pain carried via GVA sympathetic, not too painful.
External hemorrhoids below, pain carried by GSA fibers of inferior rectal nerve.
Hilton's White Line (intersphincteric groove)
Separation of internal anal sphincter (smooth muscle/autonomic) and external anal sphincter (skeletal muscle/somatic innervation)
Anal mucus glands inflamed, abscess in ischioanal fossa, can spread to other side, to anal mucosa, painful and spasms.
Painful ulceration commonly in posterior midline, presents with a "sentinel skin tag" below it, sphincter is spastic
2 openings: 1)into anal canal from infection and cryptitis spread, 2) opens into abscess in ischioanal fossa or perianal skin.
Inflammatory tract opens at anusor rectum and to skin on the other end, around anus. An abscess antedates this.
Prolapse of rectal mucosa (anal cushions), with dilated veins of internal rectal venous plexuses. Compression of veins by sphincters impedes blood flow and shows bright red bleeding. Not so painful.
Thrombosis of external rectal venous plexus, covered by skin.
Impedes venous return, IS PAINFUL.
Stretching of pudendal nerves during traumatic parturition; damage to anorectal ring.
Abscess in seminal glands
Rupture may cause pus to enter peritoneal cavity
Palpable on DRE if enlarged
Massage can release secretions for detection of gonorrhea
Benign Hypertrophy/Hyperplasia Prostate (BHP)
Middle lobe enlarges, can obstruct urethral orifice; more straining, more occlusion to urethra
Presents with nocturia, dysuria (burning sensation), urgency
Risk of cystitis and kidney damage
Initially spreads via internal iliac and sacral lymph nodes
Isthmus of cervix
Site of caesarian section
Common malignancy change of epithelium, leads to dysplasia of cells, which predisposes area to malignancy
Endopelvic fascia surrounding vagina, supports bladder in females. Weakness can predispose a multiparous woman to a cystocele, uterine prolapse.
Inflammation of a uterine tube, causes infertility due to partial blockage of the tubes
Dye coats uterus then trickles into uterine tubes and can indicate patency if accumulation fo gas bubble or radiopaque fluid
Excessive period pain
Inflammation of endometrium, predisposed to risk of ectopic pregnancy
Predisposes to uterine prolapse
Vesicovaginal (bladder-vagina), urethrovaginal, vaginoperineal, rectovaginal, usually following infection/peritonitis
Aspiration of fluid from rectouterine pouch of Douglas
Examination of uterine tube interior, instrument introduced through vagina. This can determine patency of uterine tubes
Ligation of uterine tubes
Surgical birth control, either abdominally or laparoscopically.
Collection of pus in uterine tube, and may be partly occluded by adhesions.
More likely uterine prolapse can occur. Uterus may be upright over vagina or through vagina. Exacerbated by disrupted perineal body. Can determine position by bimanual palpation.
ilioinguinal nerve block
Abolishes sensation from anterior part of perineum. Locate nerve by 2 in medial, 2 in inferior to mid inguinal point, inject anesthesia.
Used for male sterilization procedures (vasectomy)
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