Pelvic Bones

Question 1

Q: What three bones make up each side of the pelvis?

Answer 1

A: The ilium, ischium, and pubis.

Question 2

Q: Which surface of the ilium articulates with the sacrum?

Answer 2

A: The auricular surface.

Question 3

Q: What is the prominent bony landmark of the ischium that bears body weight when sitting?

Answer 3

A: The ischial tuberosity.

Question 4

Q: What is the significance of the ischial spine?

Answer 4

A: It serves as an attachment point for the sacrospinous ligament and marks the boundary between the greater and lesser sciatic notches.

Question 5

Q: What is the role of the lesser sciatic notch in the ischium?

Answer 5

A: It serves as a passageway for the obturator internus muscle and associated neurovascular structures.

Question 6

Q: What structure connects the two pubic bones at the midline?

Answer 6

A: The pubic symphysis.

Question 7

Q: What is the pectineal line, and where is it located?

Answer 7

A: The pectineal line is a ridge on the superior ramus of the pubis that serves as an attachment point for the pectineus muscle.

Question 8

Q: Which part of the pubis contributes to the formation of the obturator foramen?

Answer 8

A: The inferior and superior pubic rami.

Question 9

Q: Which part of the pubis contributes to the formation of the obturator foramen?

Answer 9

A: The inferior and superior pubic rami.

Question 10

Q: Which bones contribute to the formation of the acetabulum?

Answer 10

A: The ilium, ischium, and pubis.

Question 11

Q: What is the role of the acetabulum in the pelvis?

Answer 11

A: It serves as the socket for the head of the femur, forming the hip joint.

Question 12

Q: What is the sacral promontory, and why is it clinically significant?

Answer 12

A: The sacral promontory is the anterior projecting edge of the first sacral vertebra. It is a key landmark in obstetrics, used to measure the pelvic inlet.

Question 13

Q: What is the auricular surface of the sacrum, and what is its function?

Answer 13

A: The auricular surface is a large, ear-shaped area on the lateral aspect of the sacrum that articulates with the ilium to form the sacroiliac joint, critical for weight transfer from the spine to the pelvis.

Question 14

Q: What is the iliac crest, and what is its clinical significance?

Answer 14

A: The iliac crest is the superior border of the ilium, running from the anterior superior iliac spine (ASIS) to the posterior superior iliac spine (PSIS). It is a common site for bone graft harvesting and serves as an important landmark for lumbar punctures.

Question 15

Q: What is the function of the anterior superior iliac spine (ASIS)?

Answer 15

A: The ASIS serves as an attachment point for the inguinal ligament and the sartorius muscle, and is a key landmark for clinical procedures and surface anatomy.

Question 16

Q: What is the posterior superior iliac spine (PSIS), and how is it located externally?

Answer 16

A: The PSIS is a bony prominence on the posterior aspect of the ilium, where the iliac crest ends. Externally, it is located by the dimples of Venus on the lower back, marking the level of the second sacral vertebra.

Question 17

Q: Describe the iliac fossa and its function.

Answer 17

A: The iliac fossa is a large, concave surface on the internal aspect of the ilium. It provides an attachment point for the iliacus muscle, which is involved in hip flexion.

Question 18

Q: What is the arcuate line of the ilium, and what is its anatomical significance?

Answer 18

A: The arcuate line is a smooth, curved ridge on the internal surface of the ilium that marks the boundary between the true pelvis and the false pelvis, contributing to the pelvic brim.

Question 19

Q: What is the pubic tubercle, and what is its significance in clinical anatomy?

Answer 19

A: The pubic tubercle is a prominent bony projection on the superior aspect of the pubic bone, located near the pubic symphysis. It serves as the attachment point for the inguinal ligament, which is a key landmark in identifying the structures of the inguinal region, particularly during the assessment and surgical treatment of inguinal hernias.

Question 20

Q: What are the two main sciatic notches in the pelvis?

Answer 20

A: The two main sciatic notches are the greater sciatic notch and the lesser sciatic notch. The greater sciatic notch is located above the ischial spine, while the lesser sciatic notch is located below the ischial spine.

Question 21

Q: What structures pass through the greater sciatic notch?
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Answer 21

A: The greater sciatic notch transmits several important structures, including the sciatic nerve, the superior and inferior gluteal nerves and vessels, the pudendal nerve, and the internal pudendal vessels

Question 22

Q: What structures pass through the lesser sciatic notch?

Answer 22

A: The lesser sciatic notch transmits the tendon of the obturator internus muscle, the pudendal nerve, and the internal pudendal vessels as they enter the perineum.

Question 23

Q: What anatomical feature converts the greater sciatic notch into a foramen?

Answer 23

A: The greater sciatic notch is converted into the greater sciatic foramen by the sacrospinous ligament, which attaches to the ischial spine.

Question 24

Q: How does the pelvic inlet differ between males and females?

Answer 24

A: The pelvic inlet in females is generally wider and more circular, whereas in males it is narrower and more heart-shaped. This difference facilitates childbirth by allowing a larger birth canal.

Question 25

Q: What are the differences in the pelvic arch between males and females?

Answer 25

A: The pelvic arch (or pubic arch) in females is wider, with an angle greater than 80 degrees, while in males it is narrower, with an angle less than 70 degrees. This wider arch in females accommodates the passage of the baby during delivery.

Question 26

Q: How do the sacrum and coccyx differ between male and female pelvises?

Answer 26

A: In females, the sacrum is generally shorter and more curved, and the coccyx is more flexible and directed posteriorly. In males, the sacrum is longer and more curved, and the coccyx is less flexible and directed more anteriorly. These differences contribute to the overall shape and function of the pelvis.