1. Michael Dauzvardis, Ph.D
Know your Pelvis I + II
Michael Dauzvardis, Ph.D

2. Pelvis: objectives
List the bony/ligament components and describe sexual differences in these components.
Contrast how the greater and lesser sciatic foramina are defined.
Describe the major muscles of the pelvis along with their actions and innervations.
Sketch the branches of the internal iliac artery.
Draw the major branches of the lumbar-sacral plexus and the segmental contributions to each (e.g., pudendal - S2, 3, 4).
Describe the importance of the pectinate line with respect to the vasculature and lymphatic drainage of the rectum and anal canal.
7. Appreciate the major viscera found in the pelvis with special attention to the uterus.

3. Bones of the pelvis 1—coxal bone 2—sacrum 3—acetabulum
4—obturator foramen
The male has a narrower angle between the inferior pubic rami, narrower pelvic outlet, and more vertical iliac crests.
Bones of the pelvis

4. Ilium

5. Ischium Greater sciatic notch Ischial spine Lesser sciatic notch
Ischial tuberosity

6. Pubis Superior ramus Pectineal line Pubic tubercle Pubic crest
Pubic body
Obturator foramen
Inferior ramus

7. Meet the true pelvis

8. LIGAMENTS OF THE PELVIS:
A. Pubic Symphysis: Joins the two pubic bones
B. Sacroiliac Ligaments: From iliac to sacral tuberosities
C. Iliolumbar Ligaments: L5 transverse process to iliac crest
Sacrotuberous Ligament: from lateral sacrum and coccyx to the medial side of the ischial tuberosity.
E. Sacrospinous Ligament: from lateral sacrum and coccyx to ischial spine

9. Ligaments continued--
In the female the distance between the ischial spines (interspinous distance) can be useful in determining if a caesarian delivery is indicated
Left sacrospinous ligament is removed

10. Main contents of the pelvis
Rectum
Bladder
Uterus/vagina; prostate in males

11. Muscles of the pelvis; Obturator internus
Dauzvardis
Obturator internus

12. Muscles of the Pelvis; Piriformis
Dauzvardis
Piriformis
(nerve to piriformis)

13. Muscles of the pelvis: Pelvic diaphragm
piriformis
The pelvic diaphragm consists of levator ani + coccygeus
The levator ani inserts on the fascia of the obturator internus on an arc called the arcus tendinaes

14. Muscles of the pelvis: levator ani
The levator ani forms the main part of the pelvic diaphragm, the cranial layer of the pelvic floor. It is primarily supplied by direct branches of the sacral plexus (S3-S5). To a small degree the pudendal nerve contributes to its innervation as well.
Muscles of the pelvis: levator ani
Levator ani = iliococcygeus plus pubococcygeus

15. Muscles of the pelvis: coccygeus Levator ani COCCYGEUS
Levator ani + coccygeus = pelvic diaphragm—Keeps your guts from falling out

16. Arteries of the pelvis--overview

17. Pelvic arteries; male

18. Pelvic arteries: female
In the female the uterine artery replaces the inferior vesicle artery such that branches off the uterine and vaginal arteries feed the inferior bladder

19. Pelvic innervation
Sacral Plexus: (L4 - S5): rests on piriformis muscle, see figure above. It gives several branches to pelvis and perineum. Represents ventral rami of S1 - S4; and receives L4,L5 contribution from the lumbosacral trunk.

20. Pelvic innervation 1----subcostal 2----iliohypogastric
3----ilioinguinal
4----genitofemoral
5----lateral femoral cutaneous
6----obturator
7----femoral
8----superior gluteal
9----inferior gluteal
10—nerve to piriformis
11---peroneal portion of sciatic
12---tibial portion of sciatic
13---nerve to quadratus femoris and inferior gemellus
14---nerve to obturator internus and superior gemellus
15---posterior femoral cutaneous
16---perforating cutaneous
17---pudendal
18---nerve to levator ani
Faraz has been spotted putting ketchup on a hotdog

21. Autonomics
Lumbar splanchnics (sympathetic), sacral splanchnics (sympathetic), and pelvic splanchnics (parasympathetic) mingle with the aortic, mesenteric, and hypogastric plexi to innervate pelvic viscera.

22. Autonomics--continued
Note; sympathetic splanchnics fail to synapse in chain ganglia-they synapse in ganglia in or near target organs.

23. Sacral splanchnics
Pelvic splanchnics
Sacral symp. ganglia
Ganglion impar
Autonomics—even more
Just a nice summary slide showing how sympathetic lumbar and sacral splanchnics come off chain while pelvic splanchnics come off ventral roots (not pictured)

24. Autonomics ad nauseum
The key points to remember from these obnoxious autonomic figures:
Lumbar and sacral splanchnics are sympathetic
Pelvic splanchnics are parasympathetic
All 3 splanchnic types mingle with all or some of the SHP, IHP, and pelvic nerves
Parasympathetics make you go and point, (erection) while sympathetics make you stop going and shoot (ejaculate)
Anatomy is not always the bomb
Point and shoot

25. Pelvic viscera: rectum
Rectouterine pouch
Rectovesical pouch in males

26. Pelvic viscera: rectum
Site of internal hemmorhoids
Valves of Houston
Note: internal anal sphincter is under involuntary control—other 3 are under voluntary control (hold it!!-you can’t always blame the dog)
A rise in portal venous pressure can result in hemorrhoids where the inferior rectal veins (systemic) meet the middle rectal veins (portal).

27. Pelvic viscera: bladder
Relaxed by parasympathetics
Activated by parasympathetics
Pee and stop peeing

28. Pelvic viscera: prostate
The prostate secretions are alkaline in order to neutralize the sperm killing acid environment of the vagina
It has been said that the prostatic utricle is a remnant of the uterus in males. Colliculus means “little hill” and it is here where the ejaculatory ducts open. It is also called the Verum Montanum---?????

29. Pelvic viscera; seminal vesicles
Looks like the head of an evil wasp to me.
Secretions include: sugar fructose, proteins, citric acid, inorganic phosphorus, potassium, and prostaglandins

30. Pelvic viscera: uterus

31. Pelvic viscera: Let’s build a uterus
The uterus is a pear shaped hollow organ which lies between the rectum (posteriorly) and the bladder (anteriorly) of the female. The lumen of the uterus is continuous with the lumen of the uterine tubes.

32. The fundus is the rounded upper part of the body

33. The body makes up 2/3 of the uterus—1/3 cervix

34. The cervix in the inferior 1/3, body—superior 2/3, fundus—superior rounded part of the body. The cervical os is the opening into the uterus----It becomes more slit-like after child birth OS

37. The uterine tubes are approximately 4 inches long
The uterine tubes are approximately 4 inches long. They are attached to the fundus of the uterus. The lumen of the tube is continuous with the lumen of the uterus. The tube forms a direct connection between the uterine cavity and the peritoneal cavity. It carries the ovum to the uterine cavity. Implantation in the tube or even in the peritoneal cavity can occur and can be fatal. The tube is divided into isthmus, ampulla, infundibulum, and fimbriae.—and lies in the upper border of the broad ligament.

40. The ovary is located on the lateral pelvic wall and is attached to the posterior leaf of the broad ligament by the mesovarium (mesentery of the ovary). The ligament of the ovary slings ovary to the uterus and runs in the mesovarium. It is related to the gubernaculum of the testis. The round ligament connects the uterus to the labia majorum. The suspensory ligament of the ovary suspends the ovary laterally to the pelvic wall. It is a condensation of fascia surrounding blood vessels to the ovary and is technically part of the broad ligament. The blood supply is via the ovarian artery from the aorta.

41. The broad ligament is a fold of peritoneum which extends from the sides of the uterus to the lateral wall of the pelvis. It surrounds the uterine tubes. Laterally the broad ligament is prolonged over the ovarian vessels as the suspensory ligament of the ovary.—Again—the mesentery of the tube is the mesosalpinx and the ovary the mesovarium. Transverse cervical ligaments: from cervix to lateral walls. Uterosacral ligaments from cervix posteriorly to sacrum.

43. ureter
Uterine artery passes above ureter in base of broad ligament—remember: WATER GOES UNDER THE BRIDGE!---urine passes under the uterine artery.---many law suits following ligation of ureter during hysterectomy. Ovarian artery comes from aorta and travels in suspensory ligament. It gives off a small tubal branch . Textbooks differ—but Pansky says that the uterine and vaginal arteries arise independently from the anterior division of the internal iliac artery. The vaginal arises from the uterine in 10% of cases. The vaginal replaces the inferior vesical in the male and thus gives off small inferior vesical branches to the bladder. (a little diff from my artery drawing based on Netter in my pelvis lecture)
REMEMBER! Water under the bridge---ureter is under uterine artery.

44. Pelvic viscera: uterus—the real deal
Left tip of forceps is touching ovary—right tip near fimbria—Note round ligament

45. Pelvic viscera: uterus--summary