Pelvic Cavity

Where is the true/lesser pelvis? What does it contain?

The area between the pelvic inlet and pelvic outlet

• Plevic organs: rectum, bladder, ureters, prostate and seminal vesicles (males), vagina + uterus + ovaries (females), blood vessels, lymphatics, nerves

Where is the false/greater pelvis? What does it contain?

The area between the ala of the ilium

• Abdominal organs: ileum loops, portions of the ascending, descending, and sigmoid colon, appendix, blood vessels, lymphatics, and nerves

The _________ delineates the pelvic inlet. What are its components?

Pelvic brim

• Sacral promontory

• Iliopubic eminence

• Arcuate line

• Superior pubic ramus / pectineal line

• Sacral ala

• Pubic symphysis

Identify the colored parts

• Purple: sacral promontory

• Dark blue: sacral ala

• Green: arcuate line

• Pale blue: iliopubic eminence

• Orange: Superior pubic ramus / pectineal line

• Red: pubic symphysis

What borders the pelvic outlet

• Pubic symphysis

• Ischiopubic rami

• Ischial tuberosity

• Sacrotuberous ligament

• Coccyx

The pelvic diaphragm is the inferior muscular wall of the pelvic cavity. What muscle(s) make up this structure?

The levator ani — composed of 3 muscles:

• Puborectalis: forms a sling around the lower rectum, acts in association with the external and internal anal sphincter in the process of defecation

• Pubococcygeus: controls the flow of urine, helps reduce urinary incontinence

• Iliococcygeus: forms the midline raphe after it meets the fibers from the opposite side, provides a secure anchoring point for the pelvic floor

What nerves innervate the levator ani?

• nerve to the levator ani S3-S4

• Pudendal nerve S2-S4

• Inferior rectal nerve

Identify

1. Puborectalis

2. Pubococcygeus

3. Iliococcygeus

4. Coccygeus

5. Piriformis

Identify

1. Puborectalis

2. Pubococcygeus

3. Iliococcygeus

4. Coccygeus

5. Piriformis

What nerve innervate Coccygeus muscle?

Pudendal nerve S2-S4

Identify

1. Coccygeus

2. Piriformis

3. Iliococcygeus

4. Pubococcygeus

5. Puborectalis

Identify

1. Piriformis

2. Coccygeus

3. Iliococcygeus

4. Pubococcygeus

5. Puborectalis

Name and describe the two hiatuses of the pelvic floor

1. Urogenital hiatus → anterior gap between the medial borders of the levator ani muscles through which structures pass to enter the urogenital triangle of the perineum

2. Rectal hiatus / anal aperture → posterior opening of the pelvic floor through which the anal canal passes to enter the anal triangle region of the perineum

What’s a gender difference between the structures passing through the urogenital hiatus?

In males, the urethra only passes through the UG hiatus, whereas in females the urethra and vagina pass (although end up being separate openings)

Identify

1. Urogenital hiatus

2. Rectal hiatus

What are the three main functions of the pelvic diaphragm?

1. Supports abdominopelvic viscera; resists inferior thrust following increased intraabdominal pressure (from coughing, deep expiration, etc.)

2. Raises the pelvic floor, assisting the anterior abdominal wall in compressing the viscera

3. Maintains continence; controls rectum, urethra and vagina openings (help retain or release pee or feces)

Slide 8

Give characteristics of:

• Common iliac arteries

• Internal iliac arteries

• Bifurcates into the internal and external iliac arteries at the level of (approximately) L4

• Is the principal artery of the pelvis, supplying most of the blood to the pelvic viscera and some to the musculoskeletal part of the pelvis; also supplies branches of the gluteal, medial thigh, and perineum regions

  • Divides into anterior and posterior divisions

The posterior division of the internal iliac artery supplies ________________; it branches into… (name them)

Lower posterior abdominal wall, posterior pelvic wall, and gluteal region

1. Iliolumbar artery

2. Superior gluteal artery

   • Largest branch of the internal iliac artery

   • Terminal continuation of posterior trunk

   • Leaves the pelvic cavity through the greater sciatic foramen above the Piriformis muscle

   • Substantial contribution of blood supply of muscles and skin in gluteal region

3. Lateral sacral artery

The anterior division of the iliac artery supplies ____________ ___________; its branches are…

The pelvic viscera, perineum, gluteal region, adductor region of the thigh, and the placenta (fetus)

1. Superior vesical artery / Umbilical artery

   • Supplies superior portion of bladder and other pelvic structures

   • In fetus, carries deoxygenated blood from fetus to placenta

   • In adults, it obliterates and becomes the median umbilical ligament

2. Obturator artery

3. Inferior Vesicle Artery (male) / Vaginal Artery (female)

4. Middle rectal artery

5. Internal pudendal artery

   • Main artery of the perineum

   • Larger in males

   • Leaves pelvis below piriformis muscle in greater sciatic foramen, then enters perineum through the lesser sciatic foramen

   • Inferior rectal artery is a branch

6. Inferior gluteal artery

   • terminal branch

   • Leaves through greater sciatic foramen below the piriformis

   • Contributes blood supply to gluteal region

Which arteries (branches of anterior division) are present in females but not in males? Describe them

1. Uterine artery

   • Major blood supply to uterus, enlarges significantly during pregnancy

   • Homolog to artery to the ductus deferens in males

   • May be a branch of superior vesical artery

   • May branch directly from anterior division

2. Vaginal artery

   • May originate from uterine artery

   • Supplies vagina, inferior bladder, and rectum

   • Homolog to inferior vesical artery in males

Which artery (branch of anterior division) are present in males but not in females? Describe it

The inferior vesical artery

• Supplies the inferior bladder, prostate gland, and seminal vesicles

• Homolog to vaginal artery in females

The most distal / inferior branch of the internal iliac artery is the ____________, branching off the ____________ (from _______ trunk of internal iliac)

Inferior rectal artery, internal pudendal artery, anterior

The internal pudendal, along with the pudendal nerve, exits the __________ and re-enters the perineal region through the _________ (pudendal canal)

Greater sciatic foramen, lesser sciatic foramen

Identify

1. Iliolumbar artery

2. Superior gluteal artery

3. Lateral sacral artery

4. External iliac artery

5. Internal iliac artery

6. Common iliac artery

7. Median sacral artery

Identify SWAP red numbers 2 and 4

1. Anterior division of internal iliac artery

2. Median umbilical ligament

3. A

4. Superior vesical artery

5. Obturator artery

6. Inferior vesical artery or Umbilical artery in females

7. Middle rectal artery

8. Internal pudendal artery

9. Inferior gluteal artery

10. Same as 2 (swapped 4)

11. Not labelled

12. Inferior rectal artery

Identify

1. Iliolumbar artery

2. Lateral sacral artery

3. Superior gluteal artery

4. R internal iliac artery

5. R ureter

6. Internal pudendal artery

7. Uterine artery

8. Umbilical artery

9. Vaginal artery

10. Obturator artery

11. Superior vesical artery

12. Medial umbilical ligament

13. Anterior trunk of internal iliac artery

14. Inferior gluteal artery

15. Middle rectal artery