Lecture 2.6 - Pelvis and Perinum Flashcards
What consists in the Pelvic region?
- area of transition between trunk and lower limbs
- enclosed by bones, ligaments, and muscles
What is the difference between Pelvic inlet and Pelvic outlet?
Inlet
- marked by arcuate line of ilium and pectineal line of pubis
- superior and open to abdominal cavity
Oulet
- marked by the ischial tuberosities, pubic symphysisis and arch, and coccyx
- inferior and closed to pelvic diaphragm
– levator ani m. and coccygeus m.
Sex differences in pelves?
Male pelvis: - heart shaped inlet - smaller outlet Female pelvis: - oval shaped inlet - larger pelvis outlet, everted ischial spines - shallower greater and lesser pelves - rounded and wider subpubic angle
What is the Pelvic cavity? Divisions?
- funnel shaped space bount by the bones of the pelvis
- greater pelvis: between the ala of ilium and pelvic inlet
- lesser pelvis: between pelvic inlet/outlet
- continuous with abdominal cavity
- contains urinary bladder, terminal parts of ureters, pelvic genital organs, and recutm
What is the Perineum?
- triangular area of trunk between thighs and buttocks extending from the pubis to the coccyx
- seen best in lithotomy position - diamond shaped
- separated from pelvic cavity by the pelvic diaphragm
Perineum contents?
Males: - penis, scrotum, anus Females: - vulva (clitoris, vagina, anus Consists of 2 parts: urgenital triangle/region and anal triangle/region
Obturator Internus (OINA)
O: ilium, superior pubic ramus, ischium (anterolateral wall of lesser pelvis)
I: greater trochanter of femur
N: nerve of obturator internus
A: not relevant for pelvic diaphragm
Piriformis (OINA)
O: 2-4th sacral segments I: greater trochanter of femur N: S1-S2 A: not relevant for pelvic diaphragm runs through the greater sciatic foramen, along with lots of nerves and arteries going to the gluteal region
What is the Pelvic diaphragm and what does it do?
- = levator ani m. + coccygeus m.
- forms floor of pelvis, supporting abdominopelvic organs
- aids in urinary and fecal continence
- supports the abdominopelvic viscera during coughing, sneezing, etc.
- raises the pelvic floor during urination, vomiting, coughing, and weight lifting, increasing intra-abdominal pressure
- during parturition, supports the fetal head while the cervix dilates for delivering the baby
What is Tendinous arch of levator ani formed form?
- formed by the thickened fascia of obturator internus m.
- origin of levator ani m.
Iliococcygeus (OINA)
O: tendinous arch of obturator fascia
I: perineal body, coccyx
N: S4
A: supports pelvic viscera
Puberorectalis (OINA)
O: inferior ramus of pubis
I: rectum, prostate in males, vaginal in females
N: S4, S5
A: supports pelvic viscera
Pubococcygeneus (OINA)
O: inferior ramus of pubis, tendinous arch of obturator internus
I: coccyx
N: S4/S5
A: supports pelvic viscera
Coccygeus (OINA)
O: ischial spine
I: inferior end of sacrum, coccyx
N: S4/S5
A: supports pelvic viscera and flexes coccyx
What are the qalls of pelvic cavity posteriorly? Anteriorly? Laterally? Inferiorly? Superiorly?
Posterior: sacrum, piriform m. Anterior: pubic rami/symphysis Lateral: obturator internus Inferior: levator ani muscles, coccygeus Superior: open to abdominal cavity
What are the Arteries in Pelvis?
- aorta
- common iliac a.
- external iliac (becomes femoral a. to lower limb), and internal iliac a.
- – iliolumbar, lateral sacral, superior/inferior gluteal, internal pudendal, middle rectal, umbilical, superior/inferior vesical, obturator a.
Blood supply of pelvis mostly from internal iliac artery branches to…
To pelvic viscera: 1. umbilical a. to superior vesical a. 2. inferior vesical a (female)/uterine a. (male) 3. middle rectal To walls of pelvis: 4. lateral sacral a. 5. iliolumbar a. Exits to perimeum: 6. internal pudendal a. to inferior rectal a. Exits to lower limb: 7. obturator a. 8. superior gluteal a. 9. interior gluteal a.
Where do gonads and rectum receive their blood?
- gonads (testis and ovary) receive their blood from the abdominal aorta
- rectum receives additional blood from the inferior mesenteric artery (superior rectal artery)
What are the components of the Urinary system? What is the difference between children and adults?
- ureters: drain urine from kidneys to urinary bladder
- urinary bladder: temporarily stores urine
- urethra: conducts urine from urinary bladder to exterior
- in adults, the urinary bladder is the retropubic space within the lesser pelvis.
- in children, the bladder is in the abdomen; enters the greater pelvis at 6 years of age and the less pelvis at 16
What is the wall of the bladder made of? What sphincters are within the wall?
- wall of bladder made of detrusor muscle
- internal (involuntary) and external (voluntary) urethral sphincters help maintain urinary continence
- internal sphincter also prevents semen from entering bladder during ejaculation
Where are sympathetic and parasympathetic innervation located in urinary bladder and what do they do?
- sympathetic (T11-L2) = maintain continence by contraction of internal sphincter
- parasympathetic (S2-S4) = allows urination by relaxing internal sphincter and contracting detrusor muscle
What are the 4 parts of the male urethra?
male urethra is long and described in parts:
- intramural part
- prostatic urethra
- intermediate part
- spongy urethra
What is the function of ductus deferens? Epididymis? Seminiferous tubules?
Ductus = transmits sperm to ejaculatory duct during emission Epididymis = stores sperm prior to ejaculation Seminiferous = produces sperm
What is the pathway of the male pelvic viscera?
- the ductus deferens takes pathway superior, then posterior to the bladder to transmit sperm from epididymis of the testis to the ampulla of the ductus deferens, where it joins the duct of the seminal gland to form the ejaculatory duct
- ejaculatory duct then opens into the prostatic urethra
