Advanced Pelvic Diaphragm Quiz

Q1. Which description best defines the anatomical composition of the pelvic diaphragm?

• Paired levator ani and coccygeus muscles with their associated fascia
• Obturator internus and piriformis with the obturator membrane
• Pelvic peritoneum and endopelvic fascia without muscle
• Superficial and deep transverse perineal muscles only

Q2. Why is the pelvic diaphragm described as funnel shaped?

• Its fibers form a cylindrical tube around the pelvic inlet
• Its muscular sheets slope inferiorly and medially toward the pelvic outlets
• It surrounds the femoral heads bilaterally
• It projects superiorly into the abdominal cavity as a cone

Q3. Which mechanism allows the pelvic diaphragm to contribute to fecal continence without directly functioning as the external anal sphincter?

• Iliococcygeus completely occludes the anal canal
• Puborectalis maintains the anorectal angle
• Coccygeus constricts the rectal lumen
• Obturator internus closes the anal opening

Q4. A bilateral loss of levator ani tone would most directly predispose a patient to which problem?

• Femoral neck fracture
• Sacroiliac joint dislocation
• Obturator artery occlusion
• Pelvic organ prolapse

Q5. Why is the levator hiatus a potential site of pelvic floor weakness?

• It is a necessary opening whose excessive widening can reduce visceral support
• It divides the greater and lesser pelvis
• It normally contains the sciatic nerve
• It contains no surrounding muscle

Q6. During vaginal childbirth, which change places the pelvic diaphragm at particular risk of injury?

• Contraction of obturator internus around the cervix
• Closure of the pelvic inlet by coccygeus
• Marked stretching of levator ani and widening of the pelvic floor opening
• Fusion of the pubic symphysis

Q7. Which functional response of the pelvic diaphragm is expected immediately before or during a cough?

• Posterior rotation of the sacrum
• Relaxation to widen the levator hiatus
• Contraction to close the ureters
• Contraction to counter increased downward pressure

Q8. Which combination of structures provides both dynamic and passive support to the pelvic viscera?

• Pelvic diaphragm and endopelvic fascia
• Piriformis and sacral plexus
• Gluteus maximus and sacrotuberous ligament
• Obturator internus and obturator nerve

Q9. A patient paradoxically contracts puborectalis while attempting defecation. What is the most direct mechanical consequence?

• The urethra becomes completely occluded
• The coccyx dislocates anteriorly
• The levator hiatus becomes permanently enlarged
• The anorectal angle remains relatively acute and obstructs evacuation

Q10. Which statement best integrates the anatomy and function of the pelvic diaphragm?

• It forms the pelvic inlet and has no role in pelvic organ support
• It forms a muscular and fascial pelvic floor that supports viscera, accommodates pelvic passages, and contributes to continence
• It consists mainly of obturator internus and functions primarily in hip rotation
• It is a rigid fascial plate that completely closes the inferior pelvis