Chapter 17, Problem 1GAQ

a.

Summary Introduction

To determine: The pelvic girdle motions occurring in the sagittal plane around the frontal axis.

Introduction: Pelvic girdle is also called as pelvis. It is a ring-like bony structure formed by a single bone. It is located in the lower part of the trunk and it connects the axial skeleton to the lower limbs.

Explanation of Solution

When the front of the pelvis drops in association with the back of the pelvis, moving the anterior superior iliac spine anterior to the pubic symphysis is called as anterior pelvic girdle tilt and opposite to this, back of pelvis drops and front rises and moving the anterior superior iliac spine posterior to the pubic symphysis is called as posterior pelvic girdle tilt. These are the two motions that occur in the sagittal plane around the frontal axis.

b.

Summary Introduction

To determine: The pelvic girdle motions that occur in the frontal plane around the sagittal axis.

Explanation of Solution

The pelvic girdle moves as a whole unit, one side goes up and the other side goes down. The lateral tilt occurs when the two iliac crests are not leveled. The lateral pelvis tilt motion occurs in the frontal plane around the sagittal axis.

c.

Summary Introduction

To determine: The pelvic girdle motions that occur in the transverse plane around the vertical axis.

Explanation of Solution

When one side of the pelvic girdle goes forward or backward in relation to the other side, it results in pelvic rotation. The pelvic girdle rotation occurs in the transverse plane around the vertical axis. The point of reference is used to identify the direction of rotation of the pelvis.