Advanced Sacrum Quiz

Q1. Which sacral landmark forms the posterior boundary of the pelvic inlet in the midline?

• Sacral cornu
• Sacral hiatus
• Sacral promontory
• Median sacral crest

Q2. Why is the sacral promontory important in obstetric pelvimetry?

• It marks the opening of the obturator canal
• It forms the lateral boundary of the pelvic outlet
• It forms the acetabular roof
• It provides a reference point for assessing pelvic inlet dimensions

Q3. Which structures occupy the sacral canal below the termination of the dural sac?

• Sacral and coccygeal nerve roots and the filum terminale externum
• The obturator nerve and vein only
• The femoral nerve and artery
• The spinal cord itself in normal adults

Q4. Why is the sacral hiatus clinically important for caudal epidural anesthesia?

• It provides access to the epidural space within the sacral canal
• It provides direct access to the hip joint
• It opens into the obturator canal
• It contains the femoral artery

Q5. Which ligament attaches strongly to the rough sacral tuberosity posterior to the auricular surface?

• Inguinal ligament
• Transverse acetabular ligament
• Iliofemoral ligament
• Interosseous sacroiliac ligament

Q6. What is sacralization?

• Fusion of the sacrum with both femora
• Separation of S1 from the remainder of the sacrum
• Absence of the coccyx
• Partial or complete incorporation of the lowest lumbar vertebra into the sacrum

Q7. What is lumbarization of S1?

• Partial or complete separation of S1 from the remainder of the sacrum
• Failure of the pubic symphysis to form
• Fusion of S5 with the coccyx
• Fusion of L5 with the sacrum

Q8. Which statement best describes the role of the sacrum in transmission of body weight?

• It transmits axial load from L5 to the hip bones through the sacroiliac joints
• It has no role in load transmission
• It transfers all body weight directly to the coccyx
• It bypasses the hip bones and transfers weight directly to the femora

Q9. Why is the sacrum described as a keystone of the pelvic ring?

• It prevents any force from reaching the lower limbs
• It is wedged between the hip bones and transfers axial forces into the pelvic girdle
• It freely rotates between the femoral heads
• It forms the anterior wall of the abdomen

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

• It is a freely mobile bone that primarily forms the hip socket
• It is formed by fused thoracic vertebrae and supports the ribs
• It is formed by fused sacral vertebrae and connects the vertebral column with the pelvic girdle while transmitting load and protecting neural structures
• It forms only the anterior boundary of the pelvic outlet