Chapter 17, Problem 1PL

Pre-Lab Questions Select the correct answer for each ofthe following questions:

1. The two hip (coxal) bones articulate anteriorly at the

1. acetabulum.
2. pubic arch.
3. sacroiliac joint.
4. pubic symphysis.

Summary Introduction

Introduction:

The hip bone or the coxal bone is a big and irregular bone. It is narrow in the center and is expanded from below and above. In some vertebrates, including humans before puberty, it consists of 3 parts: the ilium, ischium, and the pubis. At the time of birth, the 3 bones are separated from each other by the hyaline cartilage. In the acetabulum, they are joined with each other by forming a Y-shaped portion of the cartilage.

Answer to Problem 1PL

The correct answer is option (d) pubic symphysis.

Explanation of Solution

Explanation/justification for the correct answer:

Option (d) pubic symphysis.

The 2 hip bones are joined at the points which is known as the pubic symphysis. The pubic symphysis is a cartilaginous joint which joins the right and left superior rami of the pubic bones. The analysis of the pelvis explains that the pubic symphysis works as arches. It also helps to transfer the upright trunk weight to the hips from the sacrum. The symphysis pubis also joins these 2 weight-carrying arches, and the pelvic region, which is surrounded by the ligaments to maintain the mechanical integrity. Specifically, it is found in the front of the bladder and above the external genitalia. During birth and pregnancy, the pubic symphysis around which ligaments are found become flexible, that’s why the child can pass through without any difficulty or complications.

So, the correct answer is option (d).

Explanation for incorrect answer:

Option (a) acetabulum.

At the acetabulum, the head of the femur meets with the pelvis and thus forms the hip joint. The acetabulum is a concave surface of a pelvis. So, this is an incorrect answer.

Option (b) pubis arch.

The pubic arch is also known as the ischiopubic arch. It is a part of the pelvis. It is one of the 3 notches, and the one in front that separates the lower portion of the true pelvis. So, this is an incorrect answer.

Option (c) sacroiliac joint.

In humans, the sacrum supports the spine . The SI joint (SIJ) or sacroiliac joint is the joint between the ilium bones of the pelvis and the sacrum . They are connected by strong ligaments. The joint is strong enough and gives support to the entire upper body weight. So, this is an incorrect answer.

Conclusion

At the pubic symphysis, the 2 hip (coxal) bones articulate anteriorly.